研究了SiC颗粒在927oC、1027oC和1127oC空气中的高温氧化动力学. 结果表明, 温度越高SiC颗粒的氧化速率常数越大, 氧化反应越容易进行;
SiC颗粒的高温氧化分为氧化前期和氧化后期两个阶段. 氧化前期的反应速率受界面化学反应的控制; 氧化后期受扩散控制, 其表观活化能远比氧化前期的大. SiC颗粒的高温氧化过程符合两个阶段式模型: 氧化前期的氧化速率常数kc=143.37exp(-70994}/(RT))(mg m-2 min-1), 氧化后期的氧化速率常数kD=3.61108exp((-192758)(RT))(mgm-2 min-1).
The oxidation kinetics of SiC particle in air at the temperature 927oC, 1027oC, 1127oC was investigated by continuous weighing method in high temperature oxidation furnace. The results show that the oxidation rate constant increases with the rising temperature. Oxidation process of SiC particle can be divided into the earlier and the later period. Oxidation rate was controlled by surface chemical reaction in the earlier period and by diffusion in later period. Apparent activation energy in the later period is much bigger than that in the earlier period. The oxidation process conforms to two-stage model. In the earlier period kc=143.37exp((−70994)/(RT) ) (mg·m−2·min−1), In the later period kD=3.61×108exp(−192758 RT )(mg·m−2·min−1)
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