High temperature oxidation behavior of two kinds of nitride bonded SiC based refractories was investigated at 1 100 1 500 ℃ by means of X-ray diffractometer, scanning electronic microscopy and thermogravimetry. The results show that: ( 1) with the temperature increasing,the oxidation mass increment rate of the specimen increases first and then decreases,and oxidation passivation occurs; ( 2) the oxidation resistance of SiAlON bonded SiC refractories is superior to that of Si3N4 bonded SiC refractories; ( 3) high temperature oxidation results in the increase of compressive strength at room temperature of SiC based refractories compared with specimen before oxidation; the compressive strength of SiAlON bonded SiC specimens oxidized at high temperatures decreases with the increase of the temperature as a result of formation and burst of surface bubble,while the decrease of compressive strength of Si3N4 bonded SiC specimens oxidized at high temperatures is owing to the increase of the consistency of net-like crack associated with cristobalite transformation during cooling.
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