Effects of polymer-derived ZiC interlayer on mechanical properties and ablation performance of C/C-ZiC-ZrC-SiC composites prepared by RMI

C/C-ZiC-ZrC-SiC composites were prepared by a combination of PIP (polymer infiltration & pyrolysis) and RMI (reactive melt infiltration) processes on porous C/C composites. The PIP is used for preparing a ZrC-SiC interlayer (denoted as ZiC) between the C/C composites and ZrC-SiC matrix prepared by RMI. Mechanical properties and microstructure of the composites with and without ZiC were characterized. The results show that, the increase of both flexural and tensile strength of the composites after RMI can be optimized by adjusting the ZiC and achieves 50.54% and 56.76%, respectively. The mechanisms can be attributed to the facts that the ZiC effectively protects carbon fibers and PyC from serious erosion by high-temperature melt and weakens the interfacial bond between ceramic matrix and carbon fibers, ensuring a series of stress release under external load. Interestingly, the composites with ZiC also exhibit enhanced ablation performance at ca. 2200 degrees C due to the improved ZrC content.