【摘要】 利用X-射线衍射仪、扫描电子显微镜、压汞仪和热重分析仪等手段,在1 100～1 500℃范围内研究Si3N4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,试样氧化质量增加速率降低;随氧化温度升高出现氧化钝化现象,使Si3N4结合SiC复相材料表现出很好的高温抗氧化性能;高温氧化使Si3N4结合SiC复相材料显气孔率降低,常温抗压强度升高,由于氧化层表面裂纹形成使氧化后试样的常温耐压强度随氧化温度升高而降低。更多还原

【Abstract】 High temperature oxidation behavior of Si3N4-bonded SiC multiphase material was investigated in the temperature range of 1 100 to 1 500 ℃ by means of X-ray diffractometer,scanning electronic microscopy,mercury injection apparatus and thermogravimetry.The results show that the oxidation weight increment rate of sample decreases with increasing oxidation temperature due to the formation of dense oxidation layer.Oxidation passivation occurs with the increase of oxidation temperature,so Si3N4-bonded SiC multiphase materials have excellent oxidation resistance.High temperature oxidation of Si3N4-bonded SiC multiphase material results in the decrease of apparent porosity and increase of compressive strength at room temperature.The compressive strength of samples oxidized at high temperature decreases with the increase of oxidation temperature as a result of the formation of surface crack.更多还原