Elisa Salvador

Jean-Paul Simon

Pierre-Jean Benghozi

Facing Disruption: The Cinema Value Chain in the Digital Age

Introduction 1

Cultural and Creative Industries (CCIs) have attracted growing attention in the grey and scientific literatures since the turn of the millennium [START_REF] Flew | Creative industries after the first decade of debate[END_REF][START_REF] Cinnéide | Creative entrepreneurship in the arts: Transforming 'old' into 'new' -Irish dance and music test cases such as Riverdance and Lord of the Dance[END_REF]UNCTAD 2010). Government reports on strategy are appearing 2 and academics are focusing on various aspects of CCI growth and development from different perspectives (see, e.g., [START_REF] Benghozi | When organizations in the cultural industries seek new business models: A case study of the French online press[END_REF]Benghozi andSalvador 2015, 2016;[START_REF] Caves | Creative industries: Contracts between art and commerce[END_REF][START_REF] Crane | Global culture: Media, arts, policy, and globalization[END_REF][START_REF] Flew | The creative industries: Culture and policy[END_REF][START_REF] Florida | The rise of the creative class, and how it is transforming work, leisure and everyday life[END_REF][START_REF] Lazzeretti | Creative industries and innovation in Europe: Concepts, measures and comparative case studies[END_REF][START_REF] Moreau | Four business models in contemporary art[END_REF][START_REF] Poettschacher | Strategic creativity: How values, beliefs and assumptions drive entrepreneurs in the creative industries[END_REF][START_REF] Scott | Creative cities: Conceptual issues and policy questions[END_REF][START_REF] Taylor | Contemporary identities of creativity and creative work[END_REF]. Also, special issues of scientific journals are appearing regularly, 3 attesting to the increased importance of these industries.

One of the main issues of CCIs in the digital age is their ambiguous status (industrial, technical and cultural), which makes them difficult to define and classify. 4 One aspect not yet fully investigated is the consequences of the growing influence of innovation and technology, especially following the digital revolution [START_REF] Granados | How do creative industries innovate? A model proposal[END_REF][START_REF] Karimi | The role of dynamic capabilities in responding to digital disruption: A factor-based study of the newspaper industry[END_REF][START_REF] Protogerou | Innovation in the European creative industries: A firm-level empirical approach[END_REF]. This is surprising given the clear link between creativity and innovation [START_REF] Sarooghi | Examining the relationship between creativity and innovation: A meta-analysis of organizational, cultural, and environmental factors[END_REF]. It is of pivotal importance because the competition has accelerated since the mainstream adoption of the Internet, thus highlighting a strengthening of the link between technology and competition since the mid-1990s (McAfee and[START_REF] Mcafee | Investing in the IT that makes a competitive difference[END_REF]. According to [START_REF] Abbasi | Technology roadmap for the creative industries[END_REF], "innovation and creativity have become broadly used terms in many national development strategies that can lead to growth" (p. 41). Nevertheless, CCI companies are known for their limited investment in innovation and research and development (R&D). 5 Academics and consultants tend to agree that most R&D and technological innovation takes place outside CCIs and is supported by outsiders, mainly industries in the information and communication technology (ICT) sector.

The present article is aimed at portraying the new kind of interaction between technology, technology players, and content creation and production. Digitization has ushered in a new role for technology and R&D that has led to a shift in the centre of gravity of the value chain. More specifically, our study investigates the way that disruptive technologies are challenging the traditional equilibrium and the value chain of a specific industry historically impacted by technological evolution, namely cinema. Technological innovation, once limited to a subsegment of the "technical industries" 6 of cinema, has gained traction vis-à-vis the traditional creation of content. The massive global effects of technology are usually examined with no consideration given to how technologies transform the cinema value chain and organization and play a disruptive role [START_REF] Christensen | The innovator's dilemma: When new technologies cause great firms to fail[END_REF]. The aim of our study is to highlight this aspect, which is of pivotal importance in a technology-oriented industry such as cinema and in CCIs in general, where technology is not included in the management literature. Looking at specific technological impacts at the micro level instead of focusing on massive macro effects helps to fill a gap in the literature and foster improvements in public policies for the cinema industry in particular and CCIs in general.

The case of cinema may shed some light on these issues. From the start, cinema has had an important technological component and has relied on a number of crucial technological breakthroughs. [START_REF] Neal | Cinema technologies[END_REF] argue that a series of technological inventions, combined to bring about the projection of moving pictures, created the film industry. New players, usually specialized technological suppliers (STSs), are building their position by using their technological expertise to serve the creative dimension of cultural works. Shedding light on one of the most technology-based CCIs is a first step in extending the analysis to other CCIs that are more or less close to the cinema.

The specific focus on the cinema industry is also justified by the fact that ICT companies have brought about a differentiated evolution: the shooting modalities are reduced, but the fixed costs of infrastructure, postproduction and distribution are increased. Hence, the economic balance in the value chain is potentially shifting to players controlling infrastructure such as "over the top" services (e.g., Netflix), telecommunication companies and cable operators.

This article reports on an in-depth investigation of the cinema industry using different sources: desk research, a review of the grey and scientific literature in this field, and meetings with experts and industry participants. 7 Data were collected over the period March to November 2014 and updated through interviews conducted in March and April 2018. The analysis is grounded in several case studies (see Table 1). The evidence collected is used to call attention to the role of new actors and the way that technological innovation disrupts the ecosystem and legacy value chain, thus introducing a balance between legacy actors and new technological players. These features have brought about a reconfiguration of the traditional business ecosystem. By the same token, they call into question the current role of public intervention in a digital environment.

[Table 1 about here] The article is structured as follows. First we present an overview of the cinema industry and the specificities of its disruption. Then we identify the technological innovation models at work, from those incrementally enhanced by technology to full-scale disruptive models, with particular attention to the case of Netflix. In the next section we focus on the changing structure of the cinema industry, from project-based to business-based, and then illustrate the reconfiguration of the business ecosystem resulting from the active role played by new intermediaries. In the concluding section we ask whether there is a need for a new set of policies to grapple with these major changes.

One of the features of the cinema industry is that each creative project turns out to be an innovative and prototype project. Companies consider R&D more as related to investments in projects and content than as related directly to the design and innovation of processes, infrastructure and devices. Therefore, innovative activity is usually hidden within the project's production budget. However, the growing role of some of the technological elements (shooting, visual effects) combined with the (relative) significance of some of a film's budget opens up an opportunity for funding development. This promotes the growing role of new players from the information technology (IT) sector accompanied by new forms of organization of the entire value chain. Intermediaries [START_REF] Simon | The new middlemen of the digital age: The case of cinema[END_REF] and industrial partnerships are emerging in the cinema industry in the wake of the digital revolution. These new forms of relationship are not solely linked to economic dynamics; they are also the result of the evolution of technological infrastructure in the digital age [START_REF] Henfridsson | The generative mechanisms of digital infrastructure evolution[END_REF]. These developments are reflected in original new models of innovation, poorly documented in the literature 8 but well worth highlighting because they seem to include all types of innovation. Furthermore, the issue of the appropriation of digital technologies is all the more important as, in the digital age, most of the observed changes seem to be driven by new actors emerging outside the traditional sectors, while the traditional players in these industries are investing less in R&D and technology.

The Cinema Industry and Innovation in the Academic Literature

Among CCIs, cinema was one of the first to emerge (its seminal economic model was established early, at the very beginning of the 20th century). Additionally, it is far from being only a market supported by movie theatres that release films on large, wide screens [START_REF] Silver | Are movie theaters doomed? Do exhibitors see the big picture as theaters lose their competitive advantage?[END_REF] or exhibiting the "quintessential creative process" (Gil and Spiller 2007, 248). The success of cinema depends on its ability to use technology to organize itself as a service, on a rental basis, for copies to be released in theatres and for viewers to pay an admission fee ("renting their seats"). As a consequence, historically, the cinema industry was structured around three very different poles in terms of investment and business models: production (developing feature films), distribution (supporting logistics for circulating copies and providing financial intermediation to collect revenues from tickets) and exhibition (using a network of screens). Notwithstanding this seminal role, few studies have focused on the evolution strategy of the cinema andas is the case for CCIs in general [START_REF] Granados | How do creative industries innovate? A model proposal[END_REF][START_REF] Protogerou | Innovation in the European creative industries: A firm-level empirical approach[END_REF])even less on its technological and innovative aspects, even though "technology had been the source of competitive advantage" (Ghertman and Hadida 2005, 59). Rather, the literature has focused on such issues as the implications of market signalling for the cinema industry in terms of box-office performance [START_REF] Akdeniz | Cultural variations in the use of marketing signals: A multilevel analysis of the motion picture industry[END_REF], the comparative influence of institutional assets in the French and US industries [START_REF] Ghertman | Institutional assets and competitive advantages of French over U.S. cinema, 1895-1914[END_REF], historical evolution at the country level (for France, see [START_REF] Benghozi | Le cinéma[END_REF][START_REF] Benghozi | Histoire économique du cinéma français (1895-1995[END_REF], the distribution networks of Hollywood firms in the international film industry [START_REF] Shin | Global distribution networks, local exhibition alliances: Hollywood's new map in Hong Kong[END_REF] or cultural diversity 9 in the film industry [START_REF] Moreau | Cultural diversity in the movie industry: A cross-national study[END_REF]. In general, the cinema industry has been investigated from the perspective of supply and demand more than that of technological impact. For instance, [START_REF] Cartier | Impact of underlying demand and agglomeration of supply on seasonality: The case of the Hollywood film industry[END_REF] investigate the different periods used to release Hollywood films and the appropriateness of release dates in terms of the underlying demand.

In one of the few contributions examining the issue of innovation in the cinema industry, [START_REF] Silver | Are movie theaters doomed? Do exhibitors see the big picture as theaters lose their competitive advantage?[END_REF] analyze the impact of new technologies on film attendance, in particular that of the substitutes to film attendance in US theatres subsequent to the diffusion of radical innovations such as radio and television. These authors also highlight some impacts that might now appear secondary, such as the threat to movie theatres posed by the home cinema industry through large-screen televisions and the availability of broadband and video on demand. In the 1950s, the introduction of the innovative wide-screen Cinerama was the main response to the competition brought by television. The more cost-effective CinemaScope appeared a little later as one of the industry's responses to the growing success of television, differentiating itself through the offer of an alternative consumer experience. The catch-up model of Bollywood combines the new distribution technologies with improvements in quality. UFO Moviez, a pioneer in digital cinema distribution, exemplifies the revitalization of the Indian film industry. This film technology company has developed a 3D-compliant technology that has been deployed across India (see Table 1). [START_REF] Silver | Are movie theaters doomed? Do exhibitors see the big picture as theaters lose their competitive advantage?[END_REF] also argue that the cinema industry has avoided differentiation strategies and has opted for a one-size-fits-all approach to customers. This industry now faces the disruptive consequences of the digital revolution.

Differentiated Reactions to Disruptions in the Cinema Industry

The ability to innovate and mobilize new technologies in complex and dynamic environments is an important strategic resource in all cultural sectors, as [START_REF] Bhansing | Scheduled audience capacity for performing arts productions: The role of product innovativeness and organizational legitimacy[END_REF] claim in their analysis of the performing arts sector. Yet it is well known that the music industry was one of the CCIs most destabilized by the Internet revolution (Montoro-Pons and Cuadrado-Garçia 2016). [START_REF] Moreau | The disruptive nature of digitization: The case of the recorded music industry[END_REF] analyzes the disruptive nature of digitization with respect to the recorded music industry and demonstrates the confrontational reaction of the major players, which exemplifies the behaviour of companies facing disruptive innovation. The economic disruption caused by digital innovation was supported by the non-rivalry and nonexcludability characteristics of digital content. The challenge that digitization posed to the traditional music industry business model was perceived more as a threat than as an opportunity, requiring the overcoming of inertia and a radical rethinking of existing business models. This explains the delay, on the part of major companies, in adapting to digitization and in facing the threat by radical business models to decimate the revenues of incumbents by exploiting the advantages of new technologies. Streaming, consumption on demand, new actors such as Netflix, the internationalization of content and services: all these factors helped to move value along the chain to ride up towards production and ownership and video content. This movement has led to talk about a "strategy of convergence," namely "the complementary design linking the content and access industries" (Curien and Moreau 2007, 162), as access providers are increasingly interested in content.

Since the seminal contribution of [START_REF] Christensen | The innovator's dilemma: When new technologies cause great firms to fail[END_REF] regarding the theory of disruptive technologies, many studies have examined aspects linked to this theory and that of disruptive innovation, in order to determine the disruptive impact on incumbents of the business model arising from the new technologies [START_REF] Hopp | Disruptive innovation: Conceptual foundations, empirical evidence, and research opportunities in the digital age[END_REF]. The concept can be defined as follows: "the term 'disruption' delineates a process in which new entrants with generally fewer resources challenge incumbent firms" (Hopp et al. 2018, 446). [START_REF] Moreau | The disruptive nature of digitization: The case of the recorded music industry[END_REF] provides a detailed review of the theory of disruption by applying it to the music industry, where digitization has challenged the CCI business model. Furthermore, the Journal of Product Innovation Management published a special issue in 2006 titled Dialogue on the Effects of Disruptive Technology on Firms and Industries [START_REF] Danneels | From the guest editor: Dialogue on the effects of disruptive technology on firms and industries[END_REF]) and a virtual special issue in 2018 10 tracking the evolution and transformation of the concept. [START_REF] Markides | Disruptive innovation: In need of better theory[END_REF] focuses on two specific types of disruption: business-model innovation and radical product innovation. The former is defined as a new and different business model in an existing business, one that can enlarge the market by capturing new customers or encouraging existing ones to consume more. [START_REF] Markides | Disruptive innovation: In need of better theory[END_REF] argues that "business model innovators do not discover new products or services; they simply redefine what an existing product or service is and how it is provided to the customer" (p. 20). This aligns with the strategy of Netflix: redefining how content is provided to customers, which implies a new value chain structure. Disruptive business-model innovations do not completely overtake and replace the traditional way of doing business; in other words, the cinema industry will not disappear, but it has to reinvent itself.

From Fringe to Core: IT-Supported Models and the Case of Netflix

The example of Gaumont Pathé 11 in France illustrates how difficult it is for incumbents to develop a coherent and proactive strategy vis-à-vis the new opportunities brought by online services. The initiatives of this chain of movie theatres include both exploration strategies (e.g., digital projection, automated ticketing) and the dynamics of slowing down new offers appearing online (e.g., intellectual property rights tariffs, media chronology). The main thrust of the reaction of movie theatres facing the Internet challenge has been incremental innovations such as significantly improving the quality of screenings and audience comfort while maintaining the distribution structure and value chain. The strategy of the industry is, in this case, parallel to that adopted in the 1950s, with little success, by developing Cinemascope and colour to counter the equally disruptive emergence of television.

Today, the high-quality strategy adopted by Gaumont Pathé builds on client relationships, theatre armchairs, new projection techniques, and staff training. The goal is to provide a new and memorable experience (Pine and Gilmore 1998) through larger screens, immersive and more powerful sound, armchairs that move and are more comfortablein short, an "immersive cinema experience" using the latest innovative technologies. Implementation of this strategy calls for partnerships with external actors. Unforgettable effects, non-reproducible at home, and very large screens linked to very high-quality sound and images are the main objectives of supplying movies in theatres. Also, the range of services offered in theatres extends beyond the simple film-viewing experience; theatres are becoming places where people can meet before and after seeing the film for complementary activities, with impacts on the value chain. The dematerialization of ticket buying (eticketing) and fidelity cards with subscription formulas are part of the strategy. Targeting is thus improved for promotional offers, because this system enables firms to collect data on movie consumers, just as Netflix does through its algorithmic formula (see below).

Over and above marginalist responses such as that of Gaumont Pathé, CCIs have to reinvent themselves in response to the transformations brought about by digital technologies [START_REF] Mangematin | Disassembly and reassembly: An introduction to the special issue on Digital Technology and Creative Industries[END_REF]. A cross-comparison of several CCIs 12 shows that tech-supported newcomers are challenging legacy players through disruptive proposals such as original products, online and mobile channels of distribution, experimental business models, social media, and data analytics. These young companies have the capacity to use technology to create value by accessing a massive global audience. They offer unprecedented solutions for aggregating and distributing content, designing original ways of marketing and new types of transactionfor example, free subscriptions, micro-payments and premium services. One part of the value is based on the monetization of consumption forms. Another part is based on the ability to reduce the costs of production and distribution structures using crowdsourcing, 3D, virtualization or digital distribution. The issue is that these new forms of value creation and competitive positioning actually compete with older modes based essentially on the creation of content with new aesthetics.

Integrating Production and Distribution Offerings: The Disruptive Revolution Brought About by Netflix in the Legacy Value Chain

Netflix (see Table 1) is a good example of the digitization revolution. The company has extended its relationship with customers by instrumenting its apps to detect consumers' preferences. Netflix was established in 1997 as an online alternative to DVD movie rentals. The success of this niche business was supported by an innovative business model to address the problem of late fees for rentals and by an innovative algorithm to enhance customer experience through recommendation processes. The innovation brought about by Netflix involves the role of new segments of the value chain compared to a legacy value chain of just four segments: creation/production rights, aggregator/publisher, distribution, and consumption (see Figure 1). Netflix is making the most of the new segments brought about by digitization: it has introduced enabling technology services (new ways of billing and paying are important components as well) and connectivity (core network, interchange, retail Internet access). Partnerships with consumer electronics companies are also an important feature, as devices are proliferating. This case study also illustrates jumping from an upstream segment of the value chain when building a delivery network to a downstream one, with involvement not only in aggregation but also in content production. This feature illustrates the potential role of digital platforms in setting up a new balance between available brand content and original content.

[Figure 1 about here] Netflix was the first company to recognize that consumers like to view content when and where they want. Hence, its streaming format represented a threat to the traditional television business model. Netflix captures revenues directly through owning end users [START_REF] Thompson | The great unbundling[END_REF]. Its video-on-demand platform has overwhelmed traditional television players: it offers television products to consumers directly, and these products are personalized using the data collected, which allows Netflix to target programs and advertising because it knows what consumers have been watching, where they are, and when they stop watching a movie. Netflix uses this information to offer recommendations and content to its target customers [START_REF] Wessel | The problem with legacy ecosystems: They separate you from your customer[END_REF]. Predicting what customers will want to watch next is the primary goal of Netflix's data collection strategy. [START_REF] Govindarajan | The usefulness of measuring disruptiveness of innovations ex post in making ex ante predictions[END_REF] argue that the development of disruptive innovations is linked to a high level of risk and requires experimentation: lack of knowledge about new customer needs could be one of the main reasons for failure. In the case of a new actor like Netflix, this potential failure has been avoided due to the algorithm originally developed by the company to collect data on consumers and then offer them ad hoc programs in accordance with their preferences. [START_REF] Govindarajan | The usefulness of measuring disruptiveness of innovations ex post in making ex ante predictions[END_REF] even suggest that "an adhocracy culture promotes the development of disruptive innovations in an organization" (p. 17). The adhocracy culture [START_REF] Waterman | Adhocracy: The power to change[END_REF]) of flexibility, creativity, openness, risk-taking and dynamism fits well with the strategy adopted by Netflix.

However, this network activity of transforming customer relationships brings about changes in the value chain [START_REF] Wessel | The problem with legacy ecosystems: They separate you from your customer[END_REF]). Software alone is not enough. In the broader telecom, media and IT ecosystem perspective, technological intermediaries and economic actors supporting and supported by technologies, such as Google, Amazon, Apple and other Internet service providers (ISPs), dominate. This observation may signify that innovation is largely left to these challengers, who may radically disrupt the traditional industry orientations. These new players display specific value networks, including numerous technical intermediaries, in contrast with previous linear value chains. Thus, the value chain has been dramatically altered and is becoming increasingly more complex.

Challenging the Boundaries: The Emergence of Specialized Technological Suppliers

Investigating the cinema industry sheds some additional light on the revolution brought about by digitization. In addition to the disruptive changes at the distribution level that are observed in most content industries, incremental technological innovation in the cinema industry has been facilitated by original models of innovation at the production level. These models are based on particular forms of collaboration that are formalized through the decisive role of new intermediaries. 13 These new players, usually STSs, establish their position by using their expertise to serve the creative dimension of cultural works. New mediations are emerging, as revealed by the explicit responsibilities of a new role, that of supervising technical director who liaises between the core filmmaking team and the technical IT crews. In the case of Dreamworks, for instance (see Table 1), the core filmmaking team for specific endeavours includes directors, producers, production designers and visual effects (VFX) supervisors. The supervising technical director manages all the technology (software and hardware) for a feature film and defines the workflow and the process itself. This middleperson reports to the core team.

Several case studies 14 demonstrate the growing role played by these specialized IT companies (see Table 1). Analysis of some of these companies and "iconic" clusters illustrates their place and their role in the economy of the sector: the nature of the collaboration at different levels of the value chain (from the production stage to the exhibition stage), the strategy for capitalizing on competitive resources from mastering technologies (equipment, patents and know-how), the investment economy (risk-sharing and allocation of the created value), the convergence with nearby sectors, such as videogames, using multimedia developments and online distribution. From this point of view, the case of videogames, one of the CCIs born as digital, is an interesting counterpoint to prefigure some of the changes that threaten to reach the cinema. Game studios are constantly developing technological innovations and updating their business model to deal with the consequences of the digital revolution [START_REF] Parmentier | Managing creative teams in small ambidextrous organizations: The case of videogames[END_REF]. [START_REF] Le | Technological change at the heart of the creative process: Insights from the videogame industry[END_REF] show that in industries such as cinema and videogames, technology is central to the creative process, while [START_REF] Gandia | The digital revolution and convergence in the videogame and animation industries: Effects on the strategic organization of the innovation process[END_REF] details the similarity of the innovation processes of these two industries.

In the field of cinema, therefore, many high-tech companies have emerged and survived, which entails, to some extent, a renewal of the technical cinema industries of the past. These new STSs are medium-sized companies. They have mastered ICT skills overall but are active in only a small number of technical areas. Their growth model places an emphasis on specific operationsrather unusual in the cinema industrysuch as the management of assets, patenting and innovative technological spillover to other industries.

The Changing Structure of the Industry: From Project-Based to Business-Based

Innovation models, brought in by these industrial technology intermediaries, offer an opportunity for change in the culture of the cinema sector. Cinema is a prototype industry based on the production of films. Due to the uncertainty and risk of the film industry, production used to be highly organized by intermediaries according to filming activities, producer choices, staff status and compensation terms through short-term contracts for single films [START_REF] Faulkner | Short-term projects and emergent careers: Evidence from Hollywood[END_REF]. 15 However, the cinema industry model is currently evolving from this project-based organization [START_REF] Faulkner | Short-term projects and emergent careers: Evidence from Hollywood[END_REF][START_REF] Foster | The rise of Hollywood East: Regional film offices as intermediaries in film and television production clusters[END_REF][START_REF] Granados | How do creative industries innovate? A model proposal[END_REF]), its core model since the 1940s (i.e., focusing on film production through a temporary team that is disbanded once production is finished), to a business-based model in which R&D, technological accumulation and firms organized in an industrial ecosystem operate via technology companies, though these are financed mainly by the film production budget.

Two Complementary Structuring Formats

Technological innovation in the production stage in a business-based model rebalances internal relations within the sector. It redefines the competitive conditions, reorganizes value chains, and challenges the domination (mainly by large IT companies) of the distribution networks for the benefit of stakeholders at the production stage (the content producers). What may be of significance is that both the upstream and the downstream stages are actively transforming themselves rather than submitting to the unilateral dominance of one or the other. In addition, this technology-oriented shift may offer a move away from stranded investments in tailor-made but non-reusable technologies.

Finally, because of the rapidly changing technological environment, the balance between the two complementary conceptions of the industrytechnological innovation and artistic creationis evolving towards a more technological orientation, both in production and in distribution. Historically, the weight of the creative dimension and the absence of fixed production costs gave the market power to producers: they had the ability to raise funds for films by mobilizing several contributors and co-producers. Conversely, the weight of the technological dimension presupposes investment of another kind, taking place upstream and independently of the production of a given project. Hence, the technological dimension shifts the centre of gravity of the value chain by giving leadership and market power to the actors controlling this dimension, even if, like Netflix or Amazon, they are then compelled to invest in production.

Netflix, as a business-oriented service provider, can manage film projects like an innovation flow in traditional companies, giving freedom and autonomy to the teams [START_REF] Mccord | How Netflix reinvented HR[END_REF]. Greater artistic freedom is left to creators, and the teams are empowered to give the green light to projects. Conversely, with a project orientation, the studio is very dependent upon each film and is partly organized around it, which induces stronger directivity on the part of studio managers but also a lack of coherence related to the addition of projects.

Incremental or Disruptive Patterns?

Several tensions, therefore, structure the new organization of the cinema value chain. On the one hand, newcomers are introducing and mandating their own standards and business culture; in terms of film distribution, they are replacing the incumbents and imposing their rules on content producers. These IT companies are using technological resources in original wayscompletely differently from traditional content industries. Instead of merely enhancing the legacy content production process, user interfaces or distribution channels, they are building their strategy around their activities and ICT-enabled services, where content may not be the prime focus. This phenomenon is illustrated by the case of Apple, where revenues from devices dominate [START_REF] Simon | 40 ans d'Apple : au-delà du mythe[END_REF] although the company clearly benefits from the attractiveness of content to sell its products (the network effect).

On the other hand, an incremental innovation model has emerged. Specialized ICT industry suppliers are building mutually beneficial collaborative relationships with the cinema industry at the production stage, promoting a relationship based on an "art meets science" model. In addition, the relationship between production and distribution is challenged by the growing value given by the organization of demand and the structuring of consumer contributions. These new configurations are also grounded in the algorithmic economy [START_REF] Hopp | Disruptive innovation: Conceptual foundations, empirical evidence, and research opportunities in the digital age[END_REF]). On the one hand, it transforms customer relations management through prescription and recommendation processes. On the other hand, it encourages customer commitment and therefore acts as a driver for crowdsourcing. The new tools thus interact with the three historical streams of the cinema industry: production, distribution and exhibition.

Redesigning the Structure of the Industry

New relationships between new players and legacy actors are enacted through these different trends, which are contradictory but also mutually reinforcing. First, new forms of dominance have been brought in by the new players at the distribution/exhibition stage (downstream domination). Second, technological innovation has been generated by new forms of collaboration between the cinema industry and specialized technology providers at the production stage (upstream domination). Third, there has been a shift in media consumption from push to pull, which creates tension between the logic of prototype (a film) firmly rooted in this industry and the growing momentum for a logic of demand.

We observe a simultaneous modification of the economic centre of gravity (technology leadership, economic weight, investments) and of the hierarchy of the various layers in the value chain (initiative, exclusion, choice of distribution channels). Because of the fast-changing technological environment, the balance between the two complementary conceptions of the industrytechnological innovation and artistic creationis evolving towards a more technology-oriented vision, both in production and in distribution. These tensions and the reorganization of the value chain lead to sidestepping the issue of the place of innovation or R&D in order to examine the role played by the technological infrastructure.

Technology: From Externalization to Intermediation and Embeddedness in Creation

Processes and New Relations Between Players

Each film is a prototype and its production is project-driven; different players in the value chain need to be brought in for collaboration. In this project-driven prototype industry, the focus of production is usually at the creation stage during a single, non-reproducible experience, tilted towards the artistic dimension. Yet the various kinds of technology-based innovation in the movie industry support alternative development models for film production, giving a wider space to R&D by reducing the part of the artistic dimension. Digitization, combined with the growing related role of software and computer science during preproduction (previsualization), production (comprehensive computer-based film editing systems), and post-production (visual effects-VFX), has induced relationships within the various contributors of "art worlds" [START_REF] Becker | Art worlds[END_REF] to evolve in a twofold perspective. First, new members and contributors are given space due to their control of and leadership role in technology; second, the relations and market power of the incumbents and usual contributors are rebalanced and transformed. Developing movies is a structured and managed activity, bringing different kinds of resources together and taking a project management approach. There are specific opportunities for innovation, but these are difficult to capitalize on due to the lack of financial resources and the continuity of an industrial process that only large companies can monitor.

A comparative analysis of different film technology companies shows an interesting variety of situations regarding the types of technical skills and investment structures and the nature of their service offer and their positioning in the value chain (see Table 1). R&D expenditures are unevenly distributed within the three different layers of technology, the media and the telecom ecosystem. R&D is conducted primarily by equipment and service providers and IT companies; technology providers such as Akamai 16 and Avid 17 are the most R&D-intensive players. In sharp contrast, the level of expenditure in the content sector, at least by the large firms, 18 remains very low.

Technology Structuring New Spaces for Interchange and Relations

According to [START_REF] Camors | Les industries culturelles en Ile-de-France[END_REF], the decrease in the cost of hardware and software has triggered the creation of small companies operating in the special effects subsector. 19 Livingstone and Hope (2011) forecast growth in the United Kingdom, led by the videogame and visual effects industries, "where creativity meets high-tech," as they put it, or, to quote Dreamworks, "where arts meet technology" (p. 18). These "Encounters of the Third Kind" create new spaces of cooperation and coordination in the film production stream and introduce new intermediaries, such as the supervisory technical director. In other words, the development of "proprietary" software tools is a process of constant collaboration and remains under artistic guidance. At the same time, this symbiosis seems to reveal ways to move beyond one of the weaknesses of film as a prototype, namely an inability to capitalize on some of the technical achievements of film. It would seem that new technologies contribute to reconciling the two visions of cinema, one technical and one artistic, or to widening the gulf between them.

These highly specialized high-tech firms undertake product development and product innovation on behalf of clients, which resembles formalized R&D. The growing importance of R&D may bring the cinema industry closer to more standard forms of innovation, built on the accumulation of R&D and the ability to reuse/reproduce the same innovation for other projects. This new perspective leads companies to file patents in ever more distant fields, such as optical imagery for Image Metrics (see Table 1).

Digitization has enabled the technical segment of the cinema industry, previously seen as the weak link in the value chain, to flourish anew, and new start-ups have proliferated due to the decreasing cost of complex production tools (special effects). In the United Kingdom and in New Zealand, this technical element has become the research branch of the film industry, guided by the artistic brief but going beyond the part it used to play in the project management of a film and beyond the film as a single but ephemeral laboratory. This new approach involves significant R&D expenditure. This pivotal role of technology was anticipated in the 1970s by pioneers such as Trumbull, who founded their own companies with the financial support of large studios (e.g., Paramount and MGM). Zoetrope (see Table 1) created its own enabling ecosystem, just as Netflix did around its connected device. [START_REF] Wessel | The problem with legacy ecosystems: They separate you from your customer[END_REF] show that Netflix looked for new ecosystem partners in order to monitor everything its customers do; BBC, Amazon, Apple and Google are some examples.

However, the technical industries have also been described, in the case of France, as a stagnating link in an expanding value chain (Imaginove 2014). The lack of symbiosis between filmmakers and technical industries may offer an explanation for the difficulties the subsector is facing, as leading firms such as Éclair and Technicolor (see Table 1) are on the verge of bankruptcy. The issue may turn out to be a horizontal linkage weakness, as investing in a new technology for a film without monitoring the potential technology spinoff or by-products may create stranded assets. The leading firms in the United Kingdom and New Zealand appear to have been able to overcome this hindrance. The rebirth of this segment in Britain is especially noteworthy since the British cinema almost disappeared in the 1950s, when the leading film company, Rank, decided to exit the film business and enter the IT business (at that time, largely concerned with copying machines) to become Rank Xerox. Digitization is bringing this industry back to life, and the cases reviewed in Table 1 suggest that growth is based on a market approach rather than on public subsidies or public management of the funds.

Reconfiguration of the Business Ecosystem and Value Chain and the Growing Role of Demand

In the cinema industry, as in all other CCIs, legacy players seem reluctant to embrace the changes, a reaction often linked to the weight of their legacy business models even though their revenues are declining, as in newspaper publishing [START_REF] Benghozi | When organizations in the cultural industries seek new business models: A case study of the French online press[END_REF], book publishing [START_REF] Benghozi | Investment strategies in the value chain of the book publishing sector: How and where the R&D someway matter in creative industries[END_REF] and music recording [START_REF] Blanc | Against the digital revolution? Institutional maintenance and artefacts within the French recorded music industry[END_REF][START_REF] Moyon | Rethinking business models in creative industries: The case of the French record industry[END_REF]. Despite the fact that, historically, each new technology did bring new streams or revenues (e.g., broadcasting, cable, pay TV, DVD), legacy players often fail to recognize the opportunities that are opening up.

Meanwhile, the cinema industry is witnessing the emergence of a new digital ecosystem and a new allocation of tasks, centred on the important role played by the computing and software activities of the new intermediaries. Smaller or independent sector players are seizing the opportunity to achieve more competitive positions in the value chain network. They are developing new forms of cooperation. Such specific industrial partnerships may be conceived of not in the traditional sense but, rather, as a set of industrial relations of "networked collaborators" within an ecosystem. As [START_REF] Benghozi | Are traditional industrial partnerships so strategic for research spinoff development? Some evidence from the Italian case[END_REF] put it, "a new vision of partnerships and innovative forms of contract need to be conceived in order to support a process involving research-based firms, with specific characteristics and needs, and where partners emerge usually ex-post" (p. 49). Yet, considering the creative specificity of CCIs, technological strategic partnerships are not simply traditional relations with identified industrial partners but are also influenced and shaped by artistic cooperation, thereby contributing specifically to the rearrangement of the business ecosystem.

The successful cases of Akamai (United States), Avid (United States), Weta Digital (New Zealand), Double Negative (United Kingdom), UFO Moviez (India) and Ymagis (France) (see Table 1) have also been characterized by their global approach from the inception stage. At the turn of the 19th century, the leading cinema companies were French (Éclair, Gaumont, Lumière), before Hollywood took over. Now, India is the world's largest film producer, with innovative ICT companies (Prime Focus, Reliance, UFO Moviez). Digitization is clearly modifying the scope and pace of the globalization process. Today's intermediaries indicate some potential routes to that end that may make it possible to mix short-term projects and long-term sustainability.

The case of book publishing [START_REF] Benghozi | Investment strategies in the value chain of the book publishing sector: How and where the R&D someway matter in creative industries[END_REF] indicates that adapting to the digital age may require legacy players to develop more proactive investment strategies to deal with the challenge from their powerful new competitors. Going beyond the limitations of the "film as a laboratory" model brings benefits and enables third parties to add their experience and technical achievements. Nonetheless, the newcomersnew intermediaries (including new distributors)are less susceptible to the "command and control" mode once exerted by the production segment. The investments required to produce legacy media products must include investment in software solutions and in qualified staff for the digital age.

The new configurations require new strategies and new ways to build competitive positions. Media consumption is shifting from push to pull. A larger number of distribution channels, combined with the potential to directly address the public, have reinforced the need to pay attention to audience reach/demand/distribution. In this new environment, demand is crucial. According to [START_REF] Gubbins | Audience in the mind[END_REF], "demand has become much more demanding" (p. 10), while the "film industry remains wedded to a 'push ' model" (p. 35). Gubbins (2014) also argues that "progress depends on audiences, and the current value chain and industry practices create a barrier, where [they] should provide a gate" (p. 126). IT companies can meet the needs of consumers by offering more options for audiences to view content. IT companies use technological resources in ways that are original, completely different from those used by most CCIs. Instead of merely enhancing the legacy production process of content, user interfaces or distribution channels, they build their strategy around their activities and ICTenabled services.

Discussion and Conclusions: New Models Disrupting Legacy Policies

Though the digitization of CCIs has been the subject of renewed interest in recent years, the way that these industries appropriate digital technologies and the consequences for value chain organization remain under-investigated. To our knowledge, no studies have investigated the micro-level transformations induced by the digital revolution on the value chain and organization of a specific CCI. The present article is one of the first attempts at filling this gap in terms of one of the strongest technology-based CCIs, namely the cinema industry.

Historically, cinema has undergone successive waves of technical innovation, such as the introduction of sound and colour [START_REF] Benghozi | Histoire économique du cinéma français (1895-1995[END_REF]. Emblematically and illustratively for CCIs, the cinema industry remains an intensive user of technology, incorporating a variety of innovations, with the support of a creative organizational meeting of "soft" and "hard" components, and therefore developing strong relations with R&Dintensive technology suppliers. Furthermore, the cinema industry, like other CCIs, is characterized by the ability (and the necessity) to continuously offer consumers new "creative" products; to this end, networks and alliances with external actors are necessary. [START_REF] Markides | Disruptive innovation: In need of better theory[END_REF] has even suggested the need to import the work organization of creative industries to other industries.

In this fundamentally global context, the legacy media industries in the European Union, regardless of their relative strengths, are fragmented and in no position to make the best of their own strengths. They are followers, not trendsetters. [START_REF] Tellis | Disruptive technology or visionary leadership?[END_REF] claims that incumbents are disrupted not because of emergent technological innovation but because of their lack of vision in terms of the mass market and their unwillingness to revolutionize their organization to comply with a changed context. Developing the competencies required to deal with the arrival of disruptive innovation calls for ambidexterity and an ability to overcome the competency traps [START_REF] Danneels | From the guest editor: Dialogue on the effects of disruptive technology on firms and industries[END_REF]) and myopia of the incumbents [START_REF] Hopp | Disruptive innovation: Conceptual foundations, empirical evidence, and research opportunities in the digital age[END_REF].

To take into account the new parameters of the digital environment, policy-makers need to move beyond simply supporting supply and production. One consequence of the competing distribution models of movies on digital platforms and in theatres is that the traditional media chronology (successive release according to channels) is questioned. Films produced by Netflix should, for instance, be expected to be available online only after 30 months instead of being simultaneously released in movie theatres and on Internet platforms; this is why the industry lobbied the Cannes film festival to prevent their selection and presentation at the 2018 festival.

A departure from "silo thinking" is thus required to move away from partitioning industrial policies and from any automatic funding mechanism. At the same time, the new parameters make it more difficult to identify the level at which any appropriate policy should be implemented. Should public intervention target the layer level within the ecosystem? Or should direct support be given to the sector level or a blend of sectors, to economic players or to specific players (i.e., SMEs, start-ups, middle-range film production, independent producers)?

We need to rethink the traditional frameworks of the economic analysis of culture, because the digital world is free from many constraints of the standard economic theory of culture. The digital economy is a fixed-cost industry (importance of network effects, low marginal costs) for infrastructures and digital services. It gives pivotal economic power to the leaders, it generates "natural" monopolies of actors and platforms controlling technology and infrastructures, it calls for massive investment because only the leaders survive, and it causes competitive problems because of the acquisition of dominant positions in global ecosystems of associated markets or neighbours.

A simple lesson can be drawn from the case studies listed in Table 1: the field is now swarming with STSs that are likely to have escaped any policy radar. Therefore, the real question is whether there is a need for policy. In any case, maintaining a vertical approach, "per industry," is bound to miss the point: STSs are providing services across the layers of the ecosystem and across the boundaries of established industries. The emergence of newcomers or intermediaries suggests an irreversible structural change where incumbents in the cinema industry (or other CCIs) will have to learn to live together with the new players in an ecosystem where all actors can find their place and capture customers using ad hoc competitive strategies.

Notes

Acknowledgements

A preliminary version of this article (under the title "Technological Innovation as a Disruptor: The Case of the Cinema Value Chain in the Digital Age") was presented at CONCORDi 2017, 6th European Conference on Corporate R&D and Innovation, "Innovation and Industrial Dynamics: Challenges for the Next Decade," European Commission, Joint Research Centre, Directorate for Growth and Innovation, in collaboration with OECD, Directorate for Science, Technology and Innovation, Seville, 27-29 September 2017.

Abstract

Cultural and creative industries (CCIs) are based on a capacity for innovation. Yet recent technological dynamics support disruptive ways to devise, deploy and create value from innovation. Whereas most of the literature addresses the disruptive changes in consumer practices and the business models of CCIs, this study investigates how disruptive technologies are challenging the organization and value chain of the cinema industry. Such transformations are supported by a multilayered evolution driven by technological middlemen, industrial partnerships and information technology infrastructure. First, most of the observed changes are driven by actors emerging outside CCIs, while the traditional players in these industries are investing less in R&D and technology. Second, these new players, usually specialized technological suppliers (STSs), are building their position by using their technological expertise to serve the creative dimension of cultural works. The authors make several observations about the role of these STSs and that of new industrial partnerships. Last, the growing importance of information and communication technologies and of online networks ascribes a key role to technological infrastructure and platform leadership. This multilayered influence leads to a reconfiguration of the traditional business ecosystem and value chain of the cinema industry. It also questions the current role of public intervention. In particular, one wonders whether this new environment calls for an alternative policy to the traditional silo financing (i.e., partitioning the regulation and financial support for each subsector of CCIs) that has thus far dominated.

Keywords

Creative and cultural industries, cinema industry, intermediaries, disruptive innovation, value chain

Elisa Salvador holds an international PhD in Institutions, Economics and Law from the University of Turin, Italy. She is a professor in the ESSCA School of Management, where she is in charge of the course Managing Creativity and Innovation and the research group focused on Entrepreneurship and Innovation. She has served as a researcher at Ecole Polytechnique, Paris (2012-15), focusing on a project in R&D and innovation in cultural and creative industries.

Jean-Paul Simon is the founder of JPS Public Policy Consulting, a firm specializing in media/telecom regulation and strategy. He has held various positions in the telecom industry and has worked as a senior scientist at the Institute for Prospective Technological Studies (IPTS), the European Commission and the Directorate-General JRC. He is the author of several books and articles on communication and public policy and serves on the boards of academic journals. He is a frequent speaker on telecommunications and media in Asia, Europe and the United States.

Pierre-Jean Benghozi is Research Director at the National Centre for Scientific Research (CNRS) and is a professor at École Polytechnique (Paris) and at GSEM (Geneva University). Since the early 1980s he has been developing pioneering research on information technology, telecommunications, media and culture. His most recent book deals with videogames as a cultural industry. He is a co-chair of AIMAC and serves on the boards of various international editorial and scientific committees.


Iovka Boneva

Jérémie Dusart

Daniel Fernández Álvarez

Jose Emilio

Labra Gayo

Shape Designer for ShEx and SHACL Constraints *

Keywords: RDF validation, SHACL, ShEx, Wikidata, LOD quality

We present Shape Designer, a graphical tool for building SHACL or ShEx constraints for an existing RDF dataset. Shape Designer allows to automatically extract complex constraints that are satisfied by the data. Its integrated shape editor and validator allow expert users to combine and modify these constraints in order to build an arbitrarily complex ShEx or SHACL schema.

Introduction

The Shape Constraint Language (SHACL) and Shape Expressions Language (ShEx) are gaining popularity for asserting quality of RDF datasets, but also for describing their structure. However, the construction of SHACL or ShEx schemas remains a difficult problem. It requires to master different tools and languages and swap between them in order to complete a schema construction task: the syntax and semantics of the constraint language, the existing validation APIs or tools, query languages, or other means of exploring the data. Shape Designer integrates all these functionalities within a single graphical user interface. It can help non expert users to grasp the structural characteristics of an RDF dataset thanks to the automatic construction of valid constraints. Expert users on the other hand can use constraint patterns to parameterize the automatic extraction algorithm, use the schema editor to build a complex schema, and test the quality of the schema or the data thanks to the integrated validator.

In this demo we present two use cases of Shape Designer. The tool and user documentation are available on https://gitlab.inria.fr/jdusart/shexjapp.

Tool Overview

A Shape Designer project is associated with an RDF graph G and a ShEx or SHACL schema under construction S. The language to use for the schema, (2) a list of node selection queries; (3) an editing area containing the schema under construction S; (4) a validation view (not shown in Fig. 1).

The main functionality of Shape Designer is the automatic construction of a (ShEx or SHACL) shape constraint. For a given node selection query Q and a shape pattern P , it creates a shape constraint constr (Q, P ) that has a structure as indicated by pattern P and that is satisfied by all the nodes of G in the result of query Q. The constraint thus obtained can be added to the schema under construction, or simply used to gather information about the data.

Use Case : Constraint for every rdf:type

We demonstrate how to construct a recursive ShEx schema S that has one constraint for every rdfs:Class used in G and accounts for the references between types. We use a dataset with uniform structure from DBTunes4 .

Create the project. At project creation we choose the shape language, here ShEx, and indicate to the tool where to find the graph: in a local file, a local RDF4J database, or through a SPARQL endpoint. A new project comes with a set of predefined useful patterns. For instance, pattern

P 1 = { rdf:type [ ] ;
˜} is predefined and indicates that the constraint to be constructed should contain the list of possible values ([ ]) for property rdf:type, and a datatype or node kind value constraint ( ) for all other properties (˜). We also ask the tool to construct queries that select all nodes of some class, for all the classes that appear as objects of rdf:type in the graph. For instance, query Q Comp = SELECT ?x WHERE {?x a mo:Composition} is generated by the tool. Note that the prefixes defined in the graph can be used in queries and in patterns.

Automatic construction of shapes. Now, given P 1 and Q Comp , the tool inspects the graph and constructs constr (Q Comp , P 1 ) shown on the left hand side of Fig. 2. Remark that the cardinality of each triple constraint was automatically inferred from the data, among four possible cardinality constraints that are exactly one, optional (?), at least one (+), and any number (*). We can choose to add constr (Q Comp , P 1 ) to the schema S under construction. By repeating the construction of constr (Q C , P 1 ) for all classes C, a novice user can build a schema that models the data without need of mastering the shape constraint language.

For instance, we create shapes demo:Composer and demo:MusicalWork for the nodes with classes type:Composer and mo:MusicalWork, respectively.

Validation. At any time the user can validate graph G against the schema under construction S. The validation result is shown in a list and allows to explore the neighbourhood of nodes to help understand validation errors.

Shape patterns to explore the structure of the data. Automatic shape construction can be used to gather information about the data. Consider pattern P 2 = { mo:˜{ rdf:type [ ] } }. It indicates that we are interested only in properties with namespace mo:, and we want to retrieve the lists of rdf:types of their values. The shape constr (Q Comp , P 2 ) is presented on the right-hand side of Fig. 2 and it shows that the values of property mo:composer have class type:Composer, and the values of property mo:produced work have class mo:MusicalWork.

Editing the schema. Automatically inferred schemas use only subsets of the ShEx and SHACL languages. For instance, they never use shape references. We can create complex schemas by editing the schema under construction. For instance, using the information gathered from constr (Q Comp , P 2 ) we can introduce shape references in demo:Composition in Fig. 2 as follows.

mo:composer @demo:Composer ; mo:produced_work @demo:MusicalWork * 4 Use Case : Explore Wikidata Wikidata is (partially) crowd-sourced, thus highly heterogeneous. This is an essential difference compared to the first use case in which nodes with same rdf:type have very similar properties. Shape Designer can be used to understand the structure of Wikidata entries and assert the quality of such entries for a particular application in mind. We assume the reader familiar with the basic concepts of Wikidata (direct properties, property statements, qualifiers).

Shape Designer offers special support for Wikidata in the form of Wikidata project type that comes with predefined prefixes and patterns. Shape construction and validation are performed by querying the Wikidata SPARQL endpoint, therefore we put a limit on the number of query results. Validating the whole Wikidata set or even all entities of given type is computationally prohibitive. In this context the most useful feature of Shape Designer are patterns, as they allow to focus on a particular kind of information in Wikidata. For instance, a simple pattern for direct properties allows to get an idea on which properties can be expected for entities of given type. More complex patterns can account for the presence of absence of provenance information.

Conclusion

We have presented Shape Designer, a versatile tool for constructing shape schemas or exploring RDF datasets designed to be usable by novices and experts. Shape Designer uses ideas similar to several prototype tools for extracting ShEx or SHACL constraints from RDF graphs or from Wikidata [START_REF] Fernández-Álvarez | Inference of Latent Shape Expressions Associated to DBpedia Ontology[END_REF][START_REF] Gayo | RDFShape: An RDF playground based on Shapes[END_REF][START_REF] Principe | AB-STAT 1.0: Compute, Manage and Share Semantic Profiles of RDF Knowledge Graphs[END_REF][START_REF] Spahiu | Towards Improving the Quality of Knowledge Graphs with Data-driven Ontology Patterns and SHACL[END_REF][START_REF] Werkmeister | Schema Inference on Wikidata[END_REF]. The originality of Shape Designer lies in shape patterns that provide a general and succinct way to parametrize the automatic shape construction, and its user interface that integrates schema editor, validator, and a way to explore the data.

Shape Designer is being actively developed, in particular by adding more functionality for exploring Wikidata. In the near future we plan to extend shape patterns and the schema construction algorithm so that even more complex schemas could be built automatically, including recursive shapes.

Fig. 1 .

 1 Fig. 1. A schema under development in Shape Designer

downloaded from http://dbtune.org/classical/ on June 16, 2019.

Acknowledgments This work was partially funded by a grant from CPER Nord-Pas de Calais/FEDER DATA Advanced data science and technologies 2015-2020, by the ANR project DataCert ANR-15-CE39-0009, by the Spanish Ministry of Economy and competitiveness (Society Challenges: TIN2017-88877-R), and by the "Severo Ochoa" research program (BP17-88).


H Buscail
email: henri.buscail@uca.fr

C Issartel

F Riffard

S Perrier

F Rabaste

O Poble

C Combe

Role of Na 2 CO 3 on an AISI 330 Austenitic Stainless Steels Oxidation at 900 °C

Keywords: Oxidation, AISI 330 Alloy, Na 2 CO 3, SiO 2

This work shows the influence of sodium carbonate coatings on the austenitic AISI 330 ) oxidation during 48 h, at 900 °C. The N 2 -5vol.% H 2 gaseous environment was used to simulate industrial heat treatment conditions. Silica scale formation is promoted by low oxygen containing gaseous environments and the high alloy silicon content. On this alloy an amorphous silica scale is formed after the blank material oxidation.

It indicates that silicon is free to diffuse in the alloy and forms a silica scale at the internal interface. On Na 2 CO 3 coated specimens, no silica scale is formed. Then, sodium combines with silicon to form amorphous glass particles. A comparison has been performed with results obtained on a AISI 330Cb niobium containing alloy in the same oxidizing conditions. It is then concluded that sodium carbonate coatings could only favours silica formation on niobium containing alloy due to a reaction between sodium and niobium.

INTRODUCTION 1 Introduction

In high temperature carburising and nitriding conditions the AISI 330Cb alloy (Fe-34Ni-23Cr-1Nb-1.55Si) is generally used due to its niobium content. Niobium is often added to alloys for strengthening purposes. It is also found in some cases to improve weldability.

Niobium is a strong carbide former and influences the alloy carburization resistance. The benefits of niobium have been reported several times. [1,2] It has been indicated that niobium carbides precipitate preferentially at sites where interference with carbon diffusion in the alloy is maximal. Carburising and nitriding environments induce severe degradation of conveyor units due to a rapid weakening of the alloy. To improve the alloy carburization resistance, it is expected that the presence of an adherent oxide scale acts as a carbon and nitrogen diffusion barrier. A previous work has demonstrated that in the 800-1000 °C temperature range, the AISI 330Cb oxidation leads to a chromia scale acting as a good diffusion barrier under isothermal conditions. [3] It is also known that the external manganese chromite subscale can limit the chromia scale evaporation at high temperatures. [4] Nevertheless, after cooling to room temperature, important oxide scale spallation is observed. [3] In a recent work Gleeson demonstrated the significant effects of alloy composition on long-term, cyclic-oxidation resistance. Each of the alloys studied exhibited scale spallation. However, how spallation occurred varied between the alloys. [5] The literature also indicates that a Fe-35Ni-18Cr-2Si alloy has been studied at high temperature. [6] It has been shown that a Cr 2 O 3 scale is protective at high temperature. Nevertheless, Stevens has indicated that at temperatures higher than 1100 °C the chromium oxide CrO 3 evaporation occurs. Then, chromium depletion is observed in the oxide scale and in the alloy. Gleeson's work stated that the HR-160 alloy exhibited complete spallation owing largely to its relatively too high silicon content (2.75 wt.%). [5] However, silicon was also beneficial to promote protective scale formation when the exposed alloy was subsequently oxidised. The HR-120 alloy showed the poorest cyclicoxidation resistance, due to bad scale adhesion and the tendency of iron (33 wt.%) to oxidise.

Former studies have shown that the oxidation of the AISI 330Cb alloy at 900 °C in air lead to a poorly adherent chromia scales and did not permit a continuous silica scale formation even though the alloy contains about 2 wt.% silicon. [7][8][9] Then, the protection against corrosive environments was not ensured. One way to act on the oxide scale formation consists in modifying the gaseous environment, using inert gases. [10] Previous works have shown the effect of sodium salts coating on the high-temperature oxidation of alloys. Sodium chloride and sodium sulphate induce accelerated oxidation of chromium and hot corrosion processes. [11,12] Sodium carbonate coated Nickel-base alloys oxidised in air at 900 °C also show fluxing reactions but the morphology of the scales show less perturbation compared to sodium sulphates, sodium chlorides or sodium nitrates. [13] The effect sodium hydroxide on metallic conveyor belts as residue of the degreasing process of metallic pieces put inside heat treatment furnaces at 900 °C has been studied. The AISI 330Cb alloy is often used to build these conveyor belts. With time, the amount of sodium hydroxide can increase on the AISI 330Cb alloy surface due to residue accumulation. The low oxygen potential gaseous environment used in the study, N 2 -5vol.% H 2 , simulates industrial conditions in the heat treatment furnaces. A previous work has shown that, on the niobiumcontaining AISI 330Cb alloy, a protective SiO 2 cristobalite scale is formed when a low amount of Na 2 CO 3 is present on the surface. [14] In order to confirm the oxidation mechanism suggesting sodium and niobium interactions, it is proposed to test the effect of sodium on a niobium-free AISI 330 alloy. It sould be noticed that this alloy is also used as materials building heat treatment furnaces. Then, it is of theoretical and practical importance to better understand the chemical interactions between sodium and silicon on this niobium free alloy. The present work will focus on the influence of sodium coatings (Na 2 CO 3 ) on the AISI 330 oxidation during 48 h, at 900 °C. The exact role of sodium on the oxidation behaviour of the alloy will be examined by a comparison with previous results obtained on niobium containing AISI 330Cb alloy oxidized in the same conditions.

Materials and methods

The AISI 330 and the AISI 330Cb alloys are both austenitic stainless steels. Their compositions, in weight %, are given in table 1. 1.5 mm thick cylindrical specimens of 12 mm diameter were abraded up to the 320-grit SiC paper, then degreased with ethanol and finally dried. All oxidation tests were performed at 900 °C.

High temperature oxidation was performed during 48 h in flowing (8 l h -1 ) nitrogen containing 5 vol.% hydrogen (N 2 -5vol.% H 2 ). The residual oxygen partial pressure pO 2 = 15 ppm contained in the gas was measured by an oxygen analyser (Elcowa GPR 1200MS). The oxide scale characterisation was realised by X-ray diffraction (XRD). XRD patterns were obtained by use of a PANalytical X'pert MPD diffractometer (copper radiation,  k = 0.15406 nm). The XRD conditions were 2 scan, step 0.05° ranging from 10 to 80°, 8 s counting time. The oxide scale surface and cross-section morphologies have been observed in a JEOL 7600 scanning electron microscope (SEM) coupled with a LINK energy dispersive Xray spectroscopy (EDXS). The EDXS point analyses were performed with an electron probe focused to a 1 m spot. The sodium-hydroxide coatings were realised by using a 0.01 mol l -1 solutions. Immediately after dipping in the solution, the specimens were dried in warm flowing air at 40°C during 5 min. After coating, the specimens were weighted to determine the deposit weight per unit area. It corresponds to 7 10 -3 ± 1 10 -3 mg cm -2 . After drying, the coating was characterized by XRD and it was found that sodium hydroxide reacts with carbon dioxide present in ambient air to form sodium carbonate Na 2 CO 3 (ICDD 18-1208) figure 1. In the following, the coating will be considered as composed of Na

Results

Kinetics

Figure 2 shows the mass gain curves obtained after 48h oxidation on the AISI 330 Alloy. A comparison is made between blank and Na 2 CO 3 coated specimens. Kinetic results show that the mass gains registered on blank specimens are higher (k p = 1.4 10 -12 g 2 cm -4 s -1 ) compared to the coated specimens (k p = 0.58 10 -12 g 2 cm -4 s -1 ). Na 2 CO 3 . No cristobalite is detected on the XRD patterns indicating that the silica scale is amorphous on blank specimens and that no silicon containing oxides are formed on coated specimens. XRD patterns also confirm that the oxide scale is thinner on coated specimens.

Oxide scale structure

Figure 4 shows the SEM cross section obtained on the blank AISI 330 specimen oxidized 48 h at 900 °C in N 2 -5vol.% H 2 . It indicates that on the niobium free alloy AISI 330, silicon is free to diffuse and forms an amorphous silica layer at the internal interface. The amorphous state of the silica layer was analytically shown by XRD results given above (figure 3). The oxide scale is also clearly composed of an external Mn 1.5 Cr 1.5 O 4 layer and a Cr 2 O 3 layer between silica and manganese chromite.

Figure 5 exhibits the SEM cross section obtained on the Na 2 CO 3 coated AISI 330 specimen ( 710 -3 mg cm -2 ) oxidized 48 h at 900 °C in N 2 -5vol.% H 2 . It shows that silicon and sodium are located at the same place inside the scale showing that sodium traps silicon and hinders the silica scale formation.

Discussion

The study of niobium-free AISI 330 alloys oxidation has been performed to better understand the chemical interactions between sodium and silicon. The present work has focussed on the influence of sodium coatings (Na 2 CO 3 ) on the AISI 330 oxidation during 48 h, at 900 °C in N 2 -5vol.% H 2 gaseous environments. The exact role of sodium on the oxidation behaviour of the alloy will be discussed by a comparison with niobium containing the AISI 330Cb alloy oxidized in the same conditions. [14] Owing to the specific oxidizing conditions exposed in the present work some aspect will be also discussed. We will give some explanations concerning the effect of low oxygen partial pressure condition on the oxidation mechanism. Secondly, the expected role of silicon on the alloy oxidation will be examined.

Oxidation under low oxygen partial pressure conditions

Our results show that during the AISI 330 oxidation at 900 °C in N as demonstrated in a previous work. [10] The effect of a low oxygen environment can be compared to other works describing the effect of surface coatings limiting the oxygen access to the alloy surface. [10] Some authors have

shown that an yttrium sol-gel coating promotes a continuous silica scale formation at the internal interface on the alloy AISI 304 due to a limited access of the oxygen to the metallic surface. [22] Then, silica hinders the iron oxidation and the formation of non-protective iron oxides. [23] Even though the alloy AISI 330Cb contains 1.55 wt.% silicon, results show that no continuous silica scale formation was observed after oxidation in air, at 900 °C. Some scale spallation, observed on uncoated specimens, has also been explained by the presence of the high silicon amount in the alloy. [24] Douglass studied the Ni-2.05Si and Ni-4.45Si oxidation in oxygen for 18 hr in the temperature range 600-1000 °C. [25] This author proposed that the low silicon content alloy exhibited extensive internal oxidation and that the higher-silicon alloy formed a continuous layer of silicon-rich oxide.

Nakakubo has given oxidation results obtained on Fe-Si and Fe-Cr alloys at 850 °C. This author calculated the boundary conditions between internal and external oxidation based on the kinetic theory of the internal oxidation. [26] Onishi has also calculated the conditions at the boundary between internal to external oxidation of Si containing steels (Fe-Si alloys) at 850 °C. [27] This author has demonstrated that under low oxygen potential a very thin SiO 2 layer forms on the alloy surface because the diffusion rate of silicon is relatively high compared with that of oxygen. It is then concluded that internal oxidation occurs in a restricted oxygen partial pressure range and is limited to silicon concentrations below 1 wt.%.

The oxygen partial pressure range, in which internal oxidation can occur, decreases with increasing silicon content. When the silicon content increases, external silicon oxidation should occur.

In the present work, it is observed that under low oxygen potentials, the high silicon concentration in the AISI 330 alloy permits the rapid formation of a silica scale on the alloys surface because the diffusion rate of silicon is relatively high compared with that of oxygen (figure 3).

Silicon effect on the alloy oxidation

Figure 3 shows XRD patterns obtained on the AISI 330 alloy (niobium free) after 48 h oxidation at 900 °C, in N 2 -5%H 2 . The oxide scale is composed of Mn 1.5 Cr 1.5 O 4 and Cr 2 O 3 on the blank material and on the specimen coated with 7 10 -3 mg cm -2 Na 2 CO 3 . No silica is detected on the XRD patterns due to its amorphous state.

The effect of silicon on the oxidation process has already been examined on chromia forming alloys. It generally acts as a protective element. Even though too much silicon is detrimental for the steels mechanical properties its addition generally improves the oxidation and carburization resistance. [START_REF] Armanet | Les Editions de Physique[END_REF] Some authors stated that silicon segregates at the oxide/alloy interface and blocks the iron cationic diffusion. [START_REF] Huntz | [END_REF][30][31] Silicon is present as a silica film, which lowers the steel oxidation rate. The high silicon oxygen affinity permits its internal oxidation, developing SiO 2 precipitates close to the internal interface. [16] Then, it is reported that silica acts as a diffusion barrier and leads to the keying of the chromia scale to the substrate. [32,33] Silica will also lower the porosity at the internal interface acting as vacancies sinks. [34] Silicon reduces the amount of non-protective iron oxides inside the scale. [23] It also hinders the iron rich nodule formation. [30] It has been proposed that during the oxidation of a AISI 304 stainless steel between 900 et 1000 °C, 0.88 wt.% silicon leads to the formation of a chromia scale, even at 1000 °C. [35] Nevertheless, it appears that high silicon content induces more scale spallation between the alloy and the silica scale or at the silica/chromia interface. [30] It is the reason why silicon is generally not added at more than 1 weight %. One should also take care that the chromium presence is necessary to avoid the fayalite Fe 2 SiO 4 formation, which acts as a very poor diffusion barrier. [23] According to Stott, the necessary amount of silicon needed to the SiO 2 formation can be lowered when the chromium content increases. [36] Concerning the effect of higher silicon additions, Li compared the oxidation behaviour at 1000 °C of Ni-based alloys with and without about 2.7

wt.% Si additions. [37] From oxidation results, silicon addition improves oxidation resistance by forming a continuous SiO 2 layer at the scale/alloy interface, which resulted in decreased oxidation kinetics. The cast alloys, with silicon addition, also showed larger average effective inter-diffusion coefficients of chromium compared to the cast alloys without silicon addition.

Therefore, the silicon addition assisted in the establishment and re-formation of a chromia scale during oxidation.

On commercial alloys a discontinuous distribution of SiO 2 precipitates near the scale/alloy interface was found to be beneficial to cyclic oxidation resistance due to a keying effect. The formation of an amorphous silica inner layer was effective in reducing the oxidation rate of a Fe-9%Cr alloy to about half that of a Si-free steel at 700 °C, in steam, when alloyed with 0.5% Si. [38] Ishitsuda carried out a detailed study on the effect of Si additions between 0.06% and 0.49% on the 9Cr steel in the temperature range 500-700 °C in high pressure ( 35MPa) steam, and concluded that silicon was most effective in reducing the oxidation rate at the highest temperature tested and at the highest silicon content, where rates were reduced to 50% of that observed with the low silicon alloy. [39] In Ueda's work the establishment of a complete silica layer was responsible for the protective behaviour at high test temperatures. [40,41] In the present work kinetic results (figure 2) show that the silica scale obtained on blank specimens induces a higher mass gain compared to Na 2 CO 3 coated specimens. Silicon oxidation can contribute to this higher mass gain. It is difficult to conclude about the effect of silica on the alloy oxidation rate. To answer such a question, it should be interesting to compare the AISI 330 alloy oxidation with a silicon free alloy to have an indication about the protective role of silicon.

Figure 4 shows the SEM cross section obtained on the blank AISI 330 specimen. It indicates that on the niobium free alloy AISI 330, silicon has diffused in the alloy and forms an amorphous silica layer at the internal interface. The oxide scale is also clearly composed of an external Mn 1.5 Cr 1.5 O 4 layer and a Cr 2 O 3 layer between silica and manganese chromite. Figure 5 exhibits the SEM cross section obtained on the Na 2 CO 3 coated AISI 330 specimen (7 10 -3 mg cm -2 ) oxidized 48 h at 900 °C in N 2 -5vol.% H 2 . It shows that silicon and sodium are located at the same place inside the scale showing that sodium reacts with silicon and hinders the silica scale formation. Former studies have described the effect of sodium salts on the high-temperature oxidation of alloys. Sodium sulphate and sodium chloride generally lead to accelerated oxidation of chromium and hot corrosion processes. [11,12] Sodium carbonate coated Nickel-base alloys oxidised in air at 900 °C also show fluxing reactions but the morphology of the scales show less perturbation compared to other sodium salts. [13] In the present work, it is then proposed that the presence of a very low sodium carbonate coating ( 710 -3 mg.cm -2 ) does not lead to a higher oxidation rate at 900 °C in N 2 -5vol.% H 2 .

Niobium-silicon interactions

A previous work has shown that during the AISI 330Cb oxidation at 900 °C in N 2 -5vol.% H 2 , the 15 ppm oxygen partial pressure allows the alloying elements oxidation. On AISI 330Cb alloys, a SiO 2 cristobalite subscale is formed when a low amount of Na 2 CO 3 is present on the surface. It has been experimentally demonstrated that sodium combines with niobium to form NaNbO 3 . Then, sodium has no detrimental effect because this element is not free to induce glass formation. NaNbO 3 also hinders silicon dissolution in Nb 3 Ni 2 Si intermetallic due to the niobium consumption in the alloy close to the internal interface. Then, silicon is free to diffuse in the alloy and generates silica at the oxide/alloy interface. [14] In the present work, it then appears that on the blank AISI 330 alloy, no niobium is available to combine with silicon. Then, silicon is free to diffuse in the alloy and forms an amorphous silica scale as schematically described on (figure 6). This amorphous silica scale is not detectable by XRD (figure 3) but is clearly observed on the SEM cross section (figure 4).

During the AISI 330 Na 2 CO 3 -coated alloy oxidation, it should be remembered that no niobium is present in the substrate. Then, it is observed that no reaction between niobium and sodium (to form NaNbO 3 ) could occur as described on (figure 7). As shown on figure 5, sodium is free to react with silicon and forms glass particles incorporated inside the scale.

These glass particles are also undetectable by XRD due to their amorphous state (figure 3).

It then appears that, on a AISI 330 niobium free alloy, an amorphous silica scale is formed after the blank material oxidation. It indicates that no niobium intermetallic traps silicon in the AISI 330 alloy and silicon is free to form silica. On Na 2 CO 3 coated AISI 330 specimens, no silica scales are formed because niobium is not present to trap sodium in a NaNbO 3 compound. Then, silicon combines with sodium to form glass particles and the substrate is not able to form a silica scale at the internal interface. It obviously implies that the coating amount will be low enough to avoid any detrimental sodium carbonate effect on the surface.

Conclusions

The present work has shown the influence of sodium carbonate coatings on the austenitic AISI 330 (Fe-34Ni-23Cr-1.55Si) oxidation at 900 °C. The low oxygen containing N 2 -5vol.% H 2 gaseous environment was used to simulate industrial heat treatment conditions. Results confirm that SiO 2 formation is promoted by low oxygen containing gaseous environments and the high alloy silicon content.

On this niobium-free alloy an amorphous silica scale is formed after the blank material oxidation. It indicates that silicon is free to diffuse in the alloy and form a SiO 2 scale.

On Na 2 CO 3 AISI 330 coated specimens, no silica scale is formed because niobium is not present to trap sodium and form NaNbO 3 . Then, silicon combines with sodium to form amorphous glass particles.

A comparison has been performed with the work performed on an AISI 330Cb niobiumcontaining alloy in the same oxidizing conditions. It has been reported that, on the AISI 330Cb alloy, a SiO 2 cristobalite subscale is formed when a low amount of Na 2 CO 3 is present on the surface.

We can then conclude that sodium carbonate coatings could only favour silica formation on niobium containing alloys due to a reaction between Na and Nb. Alloy 330

2 CO 3 .

 23 figure 1.

Figure 3 exhibits 3 (

 33 Figure 3 exhibits XRD patterns obtained on the AISI 330 alloy (niobium free) after 48 h

Figure 1 :Figure 2 :

 12 Figure 1: XRD pattern obtained on the AISI 330 alloy coated with 1.401 mg cm -2 NaOHshowing that it reacts with CO 2 present in air to form Na 2 CO 3 .

Figure 3 :Figure 4 .

 34 Figure 3: XRD pattern obtained on the AISI 330 alloy (niobium free) after 48 h oxidation at

Figure 5 .

 5 Figure 5. SEM cross sections obtained on the Na 2 CO 3 coated AISI 330 specimen (7 10 -3 mg cm -2 ) oxidized 48 h at 900 °C in N 2 -5vol.% H 2 (BSE Image x 5000). Silicon and sodium are

Figure 6 .

 6 Figure 6. Schematic drawing showing the amorphous SiO 2 scale formation on the AISI 330

Figure 7 .

 7 Figure 7. Schematic drawing showing the sodium silicon interaction on the coated AISI 330

  2 -5vol.% H 2 , the 15 ppm oxygen partial pressure allows the alloying elements oxidation. This oxygen content is high enough to induce the substrate oxidation because thermodynamic data indicate that only p(O 2 ) Cr 1.5 O 4 located at the external interface, could reduce the conversion of Cr 2 O 3 into a CrO 3 volatile oxide above 1000 °C. Our XRD and SEM results indicate that after oxidation of the blank AISI 330 specimen, the scale is composed of Mn 1.5 Cr 1.5 O 4 and Cr 2 O 3 . Present results show that the silica scale formation is promoted by low oxygen containing gaseous environments such as N 2 -5vol.% H 2

	[19-21]

= 10 -22

atmosphere is necessary to oxidised chromium at 900 °C. Thermodynamic data also indicate that p(O 2 ) = 10 -30 atm. is enough to oxidised silicon at 900 °C. XRD results have shown that at 900 °C the oxide scales are mainly composed of Mn 1.5 Cr 1.5 O 4 and Cr 2 O 3 . The relatively high Mn 1.5 Cr 1.5 O 4 peaks intensities indicate that this phase is present at the external interface (figure

4

). Our results also show that manganese diffuses to the scale external interface in all cases. This phenomenon was reported by other authors.

[15][16][17]

Mn 1.5 Cr 1.5 O 4 is sometimes considered as non-protective because it presents a porous structure and a bad adherence.

[16,18]

Other authors pointed out that Mn 1.5

Table 1 .

 1 Alloys composition (weight %).

	Wt. %	Fe	Ni	Cr	Si	Nb Mn	C	P	S
	AISI 330	Bal. 34.76 18.82 1.31 0.03 1.40 0.05	0.019 0.0004
	AISI 330Cb Bal. 34.41 22.87 1.55 0.97 0.72 0.05	0.012	0.002

Graphical Abstract

On blank AISI 330, amorphous SiO 2 formation is due to silicon diffusion from the alloy to the internal interface. On Na 2 CO 3 coated specimens, no silica scales are formed because niobium is not present to combine with sodium. Then, silicon reacts with sodium to form amorphous glass particles. Sodium carbonate coatings only favour silica formation on niobium containing alloys due to a possible neutralisation of sodium by niobium.