Thermal shock resistance of a two-dimensional silicon carbon fiber reinforced SiC matrix composite

A two dimensional SiC/SiC (2D-SiC/SiC), which contains different fiber density in two reinforcing direction, were prepared by chemical vapor infiltration (CVI) to understand the effects of the fiber bundle density on the thermal shock resistance of SiC/SiC. The 2D-SiC/SiC was reinforced by a two-dimensional plain woven Hi-Nicalon silicon carbide fiber. There are 11 fiber bundles per unit centimeter in X (0°) direction and 7 bundle cm^-1 in Y (90°) direction. The composite was fabricated by a CVI process. The thermal shock resistance of the 2D-SiC/SiC was characterized by the mass variation and retained tensile properties. It can be found that the mass loss increases with increasing thermal shock cycles for both directions. The mass loss rate was gradually slow down after 300 thermal shock cycles. Few cracks could be found on the coating due to the similar coefficient of thermal expansion (CTE) between the SiC coating and the matrix.