| 摘要 |
PROBLEM TO BE SOLVED: To provide an yttria sintered compact capable of being used for a part exposed to a plasma of a plasma processing apparatus. SOLUTION: The yttria sintered compact has an average crystal diameter of not greater than 3μm, a porosity of not greater than 1% and a flexural strength of not less than 180 MPa. The yttria sintered compact may preferably have a surface roughness (Ra) of 0.05-5μm. Further, the yttria sintered compact may more preferably satisfy the relationship of the following formula (1): E≤1.20×E<SB>0</SB>(1) where E and E<SB>0</SB>in the formula (1) denote etching rates (nm/min) when performing plasma processing under the same condition to yttria sintered compacts of the same material but different in surface roughness respectively, and E<SB>0</SB>denotes an etching rate (nm/min) of the yttria sintered compact having a surface roughness (Ra) of 0.05μm. COPYRIGHT: (C)2009,JPO&INPIT
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