抄録
Hot-pressed Si3N4-32%SiC nanocomposite and monolithic Si3N4 for comparision were evaluated for oxidation resistance at 1000-1400°C in static air for 100 hr. The weight gain of Si3N4-SiC nanocomposite was similar to that of Si3N4, except 1000°C. At 1000 and 1200°C oxidation, the surface layer containing cristobalite was formed, and yttrium disilicate was observed after 1400°C oxidation. The nanocomposite did not indicate a degradation in strength and even the strength increase of 20% was observed after 1200°C oxidation, whereas the strength degradation of 20-30%, due to a pit formation, occured for Si3N4.
