高压绝缘氧化铝陶瓷涂覆层组织结构分析

The Microstructures of Coats for High-voltage Insulated 〆-Al_2O_3 Ceramics

用不同配方的 Mn、Cr、Ti混合物涂覆 α- Al2 O3绝缘陶瓷表面 ,在适当条件下进行热退火处理 ,观测了各样品的二次电子发射系数 ,表面电阻率 ,XRD。发现涂层与陶瓷基体间相互扩散 ,结合紧密 ,有平整的表面组织结构 ,形成不同新相与原 α- Al2 O3混合的表面 ;样品表面电阻率降低 ,二次电子发射系数降幅达 6 0 %～ 6 5 %。涂覆处理有利于提高真空绝缘子抗表面闪烁 。

WT5BZ]The mixed coats of Mn, Ti and Cr were applied to α Al 2O 3 insulated ceramics surface,followed by heat treatment under special conditions. The secondary electron emission coefficient, surface resistively, XRD and surface morphology of the samples were observed. It is found that the new phases form because the coats penetrate into and mix with the original α Al 2O 3 during the heat treatment, which results in the denser and smoother surface. The surface resisitivity of all the samples decrease, and the decreases in their secondary electron emission coefficient reach 60%~65%. This is helpful for increasing the resistance to surface flashover and the high voltage breakdown strength of solid insulators in high vacuum.