Silicon nitride ceramics are superior in strength at high temperature, and apply to ceramic gasturbines and fuel cells. However ceramics are brittle and sensitive to flaws. To overcome the sensitivity and improve the reliability of ceramics, we developed Si_3N_4-SiC composites which show excellent crack-healing ability. The oxidation behavior of Si_3N_4-SiC composites having crack-healing ability was investigated and compared with heat-treatment conditions. The oxidation test was carried out at 1000℃ for 500hr. The measurement of weight gain, bending strength, observation of oxidized surfaces were carried out. The main results obtained are as follows: (1) The weight gain of Si3N4-SiC composites treated crack-healing was lower. (2) The bending strength of Si_3N_4-SiC composites increased the value after oxidation. (3) The crack healing conditions are useful for the oxidation-resistance, and improving strength.
