ALUMINA-BASED SINTERED COMPACT, MEMBER FOR TREATING DEVICE USING THE SAME, TREATING DEVICE AND METHOD FOR TREATING SAMPLE

PROBLEM TO BE SOLVED: To solve a problem that the difference of tanδ between the surface layer part and the inside part in an alumina-based sintered compact easily arises and particularly in the thick article, the tanδ is low only in the surface layer and tend to be high in the inside part. SOLUTION: In the alumina-based sintered compact, the purity of alumina is ≥99.0 mass% and ≤99.7 mass% and the maximum peak intensity of α-alumina crystal phase, measured by X-ray diffraction method, is assigned to (104) plane in the surface layer part and to (116) plane in the inside part at a depth of ≥10 mm from the surface layer part. COPYRIGHT: (C)2008,JPO&INPIT