Fabrication of advanced SiC fiber/F-CVI SiC matrix composites with SiC/C multi-layer interphase

SiC/SiC composite with SiC/C multi-layer interphase coated on advanced SiC fibers was fabricated by the forced thermal-gradient chemical vapor infiltration (F-CVI) process. SEM and TEM observations verified that SiC/C multi-layer interphase was formed on SiC fibers. Both flexural and tensile strengths of SiC/SiC composite with SiC/C multi-layer interphase were approximately 10% higher than composites fabricated with single carbon interphase. The SEM observation of fracture surface for the composite with SiC/C multi-layer interphase revealed cylindrical steps formed around the fiber. Apparently several crack deflections occurred within SiC/C multi-layer interphase. Moreover, the SiC/C multi-layer applied in this study operated efficiently to improve the mechanical properties.