弥散CeO_2对高温下α－Al_2O_3氧化膜初期生长的影响

EFFECT OF CeO_2 DISPERSION ON INITIAL STAGE GROWTH OF α-Al_2O_3 OXIDE SCALE AT HIGH TEMPERATURE

在研究１０００及１１００℃下含弥散ＣｅＯ_２的ＮｉＡｌ基表面α─Ａｌ_２Ｏ_３氧化膜初期生长的微观形貌及化学组成的基础上，分析了弥散氧化物质点对氧化初期表层扩散通量的影响，解析出了氧化物质点对表层元素扩散通量的贡献项，进而研究了氧化温度、弥散氧化物质点的尺寸、含量及分布等因素对弥散氧化物质点促进Ａｌ_２Ｏ_３形成的影响，并解释了突出颗粒状生长等实验结果。同时，探讨了弥散氧化物质点促进保护性氧化膜形核和增强氧化膜再生能力的机制。

On the base of studying morphologies and compositions of the a-AlaO3 scales formed on the NiAl bases with CeO2 dispersion during initial oxidation stage at 1000 and 1100℃, the effect of the dispersive CeO2 in the NiAl base on the element diffusion flux in surface zone was analysized. According to the analytic formula for the diffusion flux. the results that the dispersive particles promote the formation of nodule-like Al2O3 oxides were explained by analysizing some influencing factors such as temperature of oxidation, size. Con tent and distribution of the dispersive particles. In the meantime. the mechanism that the dispersive particles promote the nucleation and re-formation of protective Al2O3 scale was proposed .