Comparison of Thermal and Ablation Behaviors of C/SiC Composites and C/ZrB2-SiC Composites

A comparison was presented of the thermal and ablation behaviors of two carbon fiber reinforced ceramic-matrix composites (one with a SiC matrix and the other with a ZrB(2)-SiC matrix). The C/SiC composite possessed a lower thermal conductivity (TC) and a higher emissivity in comparison to the C/ZrB(2)-SiC composite. The two composites exhibited the good ablation-resistive properties with no obvious erosion rate after the arc-heated wind tunnel ablation tests. The surface of the C/SiC composite appeared to be coarse and had many rounded protrusions while a denser and more homogeneous glass oxide scale was formed for the C/ZrB2-SiC composite. The maximum surface and back side temperatures of the C/ZrB(2)-SiC composite were about 50 degrees C lower than those of the C/SiC composite, respectively, which was mainly attributed to the evaporation of the B(2)O(3) as well as its higher TC. Crown Copyright (c) 2008 Published by Elsevier Ltd. All rights reserved.