Highly thermal conductive, sintered SiC fiber-reinforced 3D-SiC/SiC composites: experiments and finite-element analysis of the thermal diffusivity/conductivity

Chemical vapor infiltrated (CVI) and polymer impregnated and pyrolized (PIP) SiC/SiC composites were fabricated by using highly thermal conductive, sintered SiC fiber. These composites had relatively high thermal diffusivity/conductivity values, which were two or three times larger than those reinforced with Hi-Nicalon or Hi-Nicalon Type S fibers. The improvement of thermal diffusivity by using this fiber was more noticeable for PIP composites than for CVI composites. A 2D finite element thermal analysis supported the experimental results, and revealed that highly thermal conductive SiC fiber was much effective for PIP composites and that the increase of fiber volume worsened CVI composite thermal diffusivity if low thermal conductive SiC fibers were used.