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利用X-射线衍射仪、扫描电镜和热重分析仪等手段,在1100～1500℃研究了Sialon结合SiC复相材料的高温抗氧化行为。结果表明:随氧化温度升高,由于氧化致密层的形成,试样氧化增重速率降低,出现氧化钝化现象;Sialon结合SiC复相材料高温抗氧化性能优于Si3N4结合SiC复相材料;高温氧化使得SiC质复相材料常温抗压强度比氧化前提高;随氧化温度升高,Sialon结合SiC复相材料的氧化膜表面形成较多气泡和开口空洞,使耐压强度呈下降趋势;Si3N4结合SiC复相材料随氧化温度升高,耐压强度降低,这是由于冷却过程方石英化伴生的网状裂纹密度增大。
The high temperature oxidation resistance of Sialon bonded SiC composite was investigated by X-ray diffraction, scanning electron microscopy and thermogravimetric analysis at 1100-1500 ℃. The results show that with the increase of the oxidation temperature, the rate of oxidation and passivation decreases due to the formation of the oxidized densified layer, and the oxidation passivation phenomenon occurs. The high temperature oxidation resistance of Sialon bonded SiC composite is better than that of Si3N4 bonded SiC composite. As the oxidation temperature increases, more bubbles and open voids are formed on the surface of the oxide film of the SiC composite material, so that the compressive strength decreases; the Si3N4 binding SiC composite materials with the oxidation temperature increases, the compressive strength decreases, which is due to the cooling process of cristobalite associated mesh crack density increases.