New liquid processing of oxide/oxide 3D wowen ceramic matrix composites

In this work, a novel process named Flexible Injection Process (FIP) was developed to manufacture near-net shape oxide/oxide composites reinforced with 3D interlock fibers. This process uses a flexible membrane to apply pressure to promote transverse impregnation of the fibrous reinforcement by a slurry charged with sub-micron ceramic particles. Due to the through-thickness filtration and compaction, FIP process is much faster than typical in-plane impregnation and results in composites with lower residual porosity than those produced by traditional processes. In this study, a mathematical modeling of the impregnation in FIP was developed and compared to experimental infiltration experiments. Furthermore, ceramic matrix composites (CMCs) produced by FIP were compared to composites manufactured via an established RTM-like process. The two molding processes were compared to determine if the different flow behaviors have an impact on material densification, porosity formation, mechanical properties, and manufacturing time. CMCs produced by both methods resulted in similar microstructures, as determined by mercury intrusion porosimetry, even if FIP composites were marginally less porous. Finally, a comparison of mechanical properties resulting from the two manufacturing methods has shown a similar behavior. Thus, the main advantages of FIP molding were identified to be the shorter cycle time and the robustness of the impregnation compared to RTM-like processes.