Catalytic properties of ZrB2–SiC–W ultra–high temperature ceramics at moderate temperatures

Catalytic behaviors related to recombination reactions of dissociated oxygen atoms on the surface of ZrB2–SiC–W ultra–high temperature ceramic was investigated quantitatively in the temperature ranges from room temperature to 1300 K, and recombination coefficient can be obtained by the photochemical method based on spectral diagnostic techniques using microwave–discharge plasma apparatus. Oxidation of specimens even at relatively low temperature during the experiment had a significant influence on the catalytic properties of ZrB2–SiC–W ultra–high temperature ceramics, and the results revealed the detectable dependence of the catalytic properties upon environment–induced surface modification. The relationship between catalytic properties of ZrB2–SiC–W ultra–high temperature ceramics and surface microstructure was also discussed in detail.