Abstract
ZrB_2-SiC-ZrC (ZSZ) ceramics were oxidized by two different methods to evaluate their oxidation mechanism and oxidation resistance at ultra high temperature region. Firstly, ZSZs were oxidized at 1700℃ by IR image furnace. Experimental results revealed that the glass formed on specimens with ZrB_2 rich composition was flown during oxidation and removed from the surface by the airflow. These results lead to the depletion of oxidation resistance because it is attribute to formation of the glass,. In addition, ZSZs were also oxidized continuously up to 1700℃ using a zirconia ultra high temperature furnace. The result showed that the ZSZs formed oxide scale, and the specimen after the experiment still had unoxidized area. These results imply that ZSZs have resistance of the active oxidation of the SiC. The results of two oxidation tests predict that ZSZs have optimal composition, and that the oxidation mechanism at ultra high temperature region should be taken into account to determine the optimal composition.
