Missions

As part of this postdoctoral research, capillary debinding will be considered. This technique consists of extracting the molten polymer by capillary suction via a controlled heat treatment. For this, the parts are coated with a bed of ceramic powder which serves as a porous medium for the extraction of polymers in the molten state. The objective of this work is to improve the understanding of the mechanisms involved during this step, which relate to two-phase transport in porous media (imbibition, wetting, flow, etc.). The approach will be essentially experimental, combining model debinding tests on various specimens with characterizations.

Activities

• Determine the main mechanisms involved during capillary debinding through the use of specimens and model tests
• Understand the influence of processing parameters on debinding mechanisms and kinetics
• Determine the influence of the external porous medium (chemical nature, particle size, specific surface area, morphology, etc.) on the debinding process
• Improve understanding of the appearance of defects during this stage.

Skills

PhD in Materials Science, Process Engineering, or a similar field.
Required Skills: Proficiency in ceramic and composite material development processes, as well as structural, mechanical, and physicochemical characterization techniques.
English: Level B1
Personal Qualities: Rigor, autonomy, analytical skills, ability to work in a team, and good communication skills. An interest in research and innovation is essential.

Work Context

Reducing aircraft weight is a constant challenge for the aeronautics industry. The goal is to reduce fuel consumption and associated CO2 emissions, for more economical and greener air transport. Ceramic matrix composites with discontinuous reinforcements (CMC-FD) can reduce engine kerosene consumption because they tolerate high operating temperatures, do not require cooling, and are lighter than the metals currently used. However, the development of such materials via injection molding presents certain difficulties and limitations, which are the subject of this work. This study is part of the development of a new family of ceramic matrix composite materials with discontinuous reinforcements (DF). DF-CMCs have the advantage of being able to be formed by versatile processes such as injection molding or fused deposition modeling (FFF: Fused Filament Fabrication or FGF: Fused Granulate Fabrication). These processes use thermoplastic and/or thermosetting binders that must be removed after the forming step.
This debinding step is critical for the quality of the CMC, which is why it must be finely controlled to avoid any cracking or deformation of the final part. The CMC components thus obtained are almost at the final dimensions but shrinkage during sintering must still be taken into account, and their manufacture is less expensive.

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.