Oxidation Resistance Analysis of Silicon Carbide Sintered by Hot-pressing

SiC ceramic was prepared by hot-pressing method with Si as an additive.XRD,SEM,isothermal oxidation-weight gain and non-isothermal oxidation (TG) were used to study the oxidation properties of SiC.The results show that the kinetics of isothermal oxidation without pre-oxidation SiC obey a parabolic rule at 600-1 100 ℃,and the oxidation speed of SiC increased at first and then decrease with temperature increasing at 1 100-1 300 ℃.After pre-oxidation process,the kinetics of isothermal oxidation of SiC obey a linear rule in the whole experimental temperature range.The sample has a higher severe oxidation temperature than the origin sample in the non-isothermal condition.The weight gain of SiC after pre-oxidation is less than that of the origin sample remarkably.The pre-oxidation process is a useful method to improve the oxidation resistance of SiC ceramic.