高压绝缘α-Al_2O_3涂层的XPS和EELS表面分析

THE SURFACE ANALYSIS BY XPS AND EELS FOR HIGH-VOLTAGE INSULATED α-Al_2O_3 CERAMIC

用不同配方的Mn,Cr,Ti混合物涂复α－Al2O3绝缘瓷表面，在适当的条件下热处理，利用XPS和EELS测试分析了表面层的电子能态.发现在退火后各涂层成分的含量变化明显，由于配方元素不同程度地扩散、渗透进95Al2O3陶瓷基底内，通过反应生成了新相；根据价带谱和EELS分析，其表面层的价带顶移向真空能级，使能隙减小；能隙中的缺陷态、杂质态及表面态增加，有利于内次级电子的非弹性跃迁和二次电子发射系数的减小.

The mixed coats of Mn,Ti and Cr are applied to α-Al2O3 insulator,and then the heat treatment in special conditions is followed.The electronic energy states of the surface are analysed by XPS and EELS . It is found that coats components changed obviously after annealing.The new phases are formed because coats penetrate into and mix with 95 ceramic α-Al2O3.From the results of the valence-band XPS spectrum and EELS, it is suggested that the decrease of energy gaps is because their valence-band top moves towards vacuum level. The increase in density of defect state, impurity state and surface state in energy gap is beneficial to non-elastic transition of internal secondary electron. And for the decrease in secondary electron emission coefficient.