[en] Industrial needs in terms of multifunctional components are increasing. Many sectors are concerned, from the integrated direct nanoparticles production to the emerging combinations which include the metal matrix composites (MMC), ductile ceramics and ceramic matrix composites, polymer matrix composites (PMC) for bulk application and advanced surface coatings in the fields of automotive, aerospace, energy production and building applications. Moreover, domains with a planetary impact such as environmental issues, as well as aspects for instance health (toxicity) and hazard assessment (ignition and explosion severity) were also taken into account. Nanotechnologies play an important role in promoting innovation in design and realization of multifunctional products for the future, either by improving usual products or creating new functions and/or new products. Nevertheless, this huge evolution in terms of materials could only be promoted by increasing the social acceptance and by acting on the different main technological and economic challenges and developing safe oriented processes. Nowadays, a huge number of developments of nanoparticles are potentially industrial up-scalable. However, some doubts exist about the handling's safety of the current technologies. For these reasons, the main purpose was to develop a self-monitored automation in the production line coupling different techniques in order to simplify processes such as in-situ growth nanoparticles into a nanostructured matrix, over different substrates and/or the nanopowders synthesis, functionalization, dry or wet safe recovery system, granulation, consolidation in single-step, by monitoring at real time the processing parameters such as powder stoichiometry. With the aim of assuring the traceability of the product during the whole life, starting from the conception and including the R and D, the distribution and the use were also considered. The optimization in terms of processing, recovery and conditioning, permits to increase its versatility, thus leading to the increase of the added value to the production. This review put in evidence -by different examples- the progress achieved since the beginning of Nanosafe integrated initiative developed by CEA and its partners as well as promoting, firstly the safety at work place, and then extending to an integrated and controlled in-situ production by of Nanosafe-by-Design controlled processes.

[en] Additive manufacturing (AM) is rapidly expanding in many industrial applications because of the versatile possibilities of fast and complex fabrication of added value products. This manufacturing process would significantly reduce manufacturing time and development cost for nuclear components. However, the process leads to materials with complex microstructures, and their structural stability for nuclear application is still uncertain. This study focuses on 316L stainless steel fabricated by selective laser melting (SLM) in the context of nuclear application, and compares with a cold-rolled solution annealed 316L sample. The effect of heat treatment (HT) and hot isostatic pressing (HIP) on the microstructure and mechanical properties is discussed. It was found that after HT, the material microstructure remains mostly unchanged, while the HIP treatment removes the materials porosity, and partially re-crystallises the microstructure. Finally, the tensile tests showed excellent results, satisfying RCC-MR code requirements for all AM materials. (authors)

[en] AlCrN coatings were prepared by vacuum cathodic arc deposition. This low-temperature technique has been chosen due to its versatility, allowing the industrial up-scaling. In this study, the attention was focused on the correlation of the bias voltage with the resulting mechanical-tribological properties. For this purpose, the bias voltage was varied from 0 to -150 V. Indeed, the variation of grain sizes from 24 to 16 nm as well as the residual stresses from -0.68 to -8.94 GPa lead to obtain different mechanical-tribological properties. In this context, the sample deposited at -100 V exhibited an enhanced hardness (50 ± 2 GPa) and an acceptable wear resistance. (authors)

[en] For enhanced accident tolerant fuels for light water reactors application, chromium coatings on zirconium based nuclear fuel claddings are developed and studied at CEA in the framework of the French CEA-EDF-AREVA collaborative program. The results obtained so far, mainly on Zircaloy-4 substrate, show very good corrosion resistance in nominal conditions and significant enhancement of the resistance of the material to oxidation in steam at high temperature (HT), up to 1300 Celsius degrees, with a drastic decrease of hydrogen release and/or pick-up. The present paper reports some new results obtained on chromium coated Zircaloy-4 claddings tested in loss-of-coolant accident (LOCA) conditions. In order to investigate the potential effect of the coating on the cladding mechanical behavior at HT and the capacity of the coating to sustain significant substrate deformation (i.e., during ballooning until burst occurrence) without generalized cracking/peeling, a preliminary limited set of internal pressure creep and temperature ramp tests have been performed in steam environment thanks to the EDGAR facility. The thermal-mechanical tests were done for testing/burst temperatures ranging from 600 C. degrees (α_Zr phase domain) up to 1000 C. degrees (β_Zr phase domain) on 50 cm long low-tin Zircaloy-4 cladding samples with a 15 μm thick outer chromium coating. It is shown that: -) whatever the applied temperature/pressure values, the chromium coating is still fully adherent after having experienced ballooning and burst, including at the vicinity of the burst opening where the Zircaloy-4 clad substrate is highly deformed; -) a HT strengthening effect of the coating on the overall creep clad behavior is evidenced when compared to uncoated Zircaloy-4 cladding materials tested in the same conditions; -) as a consequence, it is observed that, in the 600-750 C. degrees temperature range (α_Zr phase domain) and after burst occurrence, the balloon sizes (i.e., 'uniform' and maximum hoop strains) are generally reduced when compared to uncoated materials; -) regarding the burst mechanism in the β_Zr phase temperature range (1000 C. degrees), it is interesting to observe that, even if some ballooning occurred prior to the cladding failure, the actual burst openings are generally very small (in the order of 1 mm₂ or less), reducing the risk of fuel fragments dispersal in the coolant

[en] Nano-layered TiN-CrN coatings were synthesized by cathodic arc deposition (CAD) on M2 tool steel substrates. The aim of this study was to establish a double-correlation between the influence of the bilayer period and the deposition temperature on the resulting mechanical-tribological properties. The superlattice hardening enhancement was observed in samples deposited at different temperatures - i.e. without additional heating, 300 C and 400 C. Nonetheless, the residual compressive stresses are believed to be the responsible for reducing the hardness enhancement when the deposition temperature was increased. For instance, sample deposited without additional heating presented a hardness of 48.5 ± 1.3 GPa, while by increasing the processing temperature up to 400 C it was reduced down to 31.2 ± 4.1 GPa due to the stress relaxation. Indeed, the sample deposited at low temperature which possesses the thinnest bilayer period (13 nm) exhibited better mechanical properties. On the contrary, the role of the interfaces introduced when the period is decreased seems to rule the wear resistance. (authors)

[en] This book of abstracts summarizes the content of the presentations given at the 2012 meeting of the French ceramic group. Among the 56 abstracts presented in this document, five have been selected for INIS and deal with: 1 - SiC composites/carbon nanotubes: study of the SiC matrix; 2 - Effects of UO₂ model powders characteristics on the microstructure after sintering; 3 - Elaboration of massive nano-composite ceramic objects using the 'pre-ceramic polymer' process. 4 - Study of the sintering of nanoscale silicon carbide powders, application to the elaboration of nano-structured fibers; 5 - In-situ mechanical tests of SiC fibers submitted to ion irradiation

[en] TiSiN nano-composites coatings were synthesized for the first time by a hybrid deposition technique where high power impulse (HiPIMS) and pulsed-DC (PDCMS) magnetron co-sputtering were used for Ti and Si deposition respectively in an Ar + N_2 atmosphere. For the Ti target, the deposition parameters were fixed, while the current applied to the Si target ranged from 0 to 0.9 A. Thus, the Si content in the films was adjusted from 0 to 8.8 at.% Si to allows tailoring of microstructure and mechanical properties. TiSiN grain sizes decreased from -41 to -6 nm as the coatings became more siliceous. The hardness increased from 20 ± 0.41 to 41.31 ± 2.93 GPa when the Si concentration rose from 0 to 4.4 at.% Si, but beyond this last value, hardness degrades reaching 36.1 ± 2.21 GPa at 8.8 at.% Si. The wear behaviours evaluated by ball-on-disc tests were correlated with the Hardness/Young's modulus ratio. Moreover, the silicon enhanced the oxidation resistance and the least hardness deterioration was found in the sample with the higher silicon content (8.8 at.% Si) after a thermal annealing in air (2 h/700 C). (authors)