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Reference : UMR5801-GEOCHO-003
Workplace : PESSAC
Date of publication : Friday, November 13, 2020
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 4 January 2021
Proportion of work : Full time
Remuneration : Between 2648 and 3054 euros gross monthly depending on experience
Desired level of education : PhD
Experience required : Indifferent
The matrix of SiC/SiC composites is prepared by chemical vapor infiltration of silicon carbide (CVI-SiC), impregnation of submicron SiC powder and infiltration of liquid silicon (MI). During this last step, silicon is alloyed with boron as it considerably reduces the degradation of the CVI-SiC layer at high temperature. The mechanism behind the protective effect of boron has yet to be established. On the other hand, local alterations of the SiC-CVI remain for reasons also not yet identified.
The post-doctoral fellow will be responsible for implementing all means to understand the role of boron and metallic impurities on the chemical diffusion within the liquid Si-B alloy and the reactivity at the SiC/Si-B interface.
- Synthesis of SiC-Si-B model ceramics by infiltration of porous SiC architectures with liquid silicon and Si-B alloy.
- Physico-chemical analyses of SiC-Si-B model ceramics and SiC-SiC composites by SEM-EDS, XRD, Raman spectroscopy, etc...
- Research and evaluation of methods for the precise analysis of trace elements (B, C, metallic impurities), the local atomic environment (of Si, C and B) and SiC/Si-B interfaces (main task).
- Coordination of analyses, exploitation and synthesis of results (main task).
- Organization of follow-up meetings, oral presentations, writing of reports and scientific articles.
- Experience in the synthesis of ceramics by high temperature process(es).
- Metallographic (or more specific) preparation of ceramic samples.
- Practice of basic physico-chemical characterization techniques (SEM-EDS, XRD, Raman spectroscopy...).
- Practice or theoretical knowledge of fine physico-chemical analysis of surfaces and interfaces (XPS, SIMS, TEM-EELS...).
- Good written and oral expression, in both French and English.
The Laboratory for Thermostructural Composites (LCTS) conducts fundamental and applied research on ceramic matrix composites (CMC). SiC/SiC composites are expected to replace metal alloys in hot aero engine parts. Their development and the transition to industrial scale require a perfect control of the manufacturing process in order to meet the strict criteria in terms of structure, composition, mechanical strength and corrosion resistance. The post-doctoral fellow will work under the supervision of the project managers (belonging to the "Processes" team of the lab) and in close collaboration with the members of the "Characterization" team and the Safran Ceramics follow-up engineers.
Constraints and risks
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