Thermal Fatigue Behavior of SiC/MBAS Glass Coated Carbon/Carbon Composites

The thermal fatigue behavior of C/C composites coated with the SiC/MBAS glass (MoSi_2 particle-containing boron aluminosilicate glass) coating, prepared by the two-step process of the pack cementation and procoating-sintering, was investigated in present paper. The experimental results indicated that the SiC/MBAS glass coating had an excellent thermal shock resistance in air at temperature up to 1873 K. During quick thermal cycle between 1873K and room temperature in air, the decrease of mass and mechanical property of the coated C/C composites was all slight. After thermal cycle for 50 times, the mass loss of the SiC/MBAS glass coated sample was only 0.22%; additionally, the remaining ratio of strength and modulus was no less than 95.2% and 99.4%, respectively. The decrease of the mechanical property during the thermal cycle was primarily due to the damnification of the fiber/matrix interfaces and the oxidation of the coated samples with oxygen.