YTTRIA SINTERED COMPACT AND MEMBER FOR PLASMA PROCESSING DEVICE

PROBLEM TO BE SOLVED: To provide an yttria sintered compact having high strength and low dielectric loss. SOLUTION: The yttria sintered compact contains at least 99.9 mass% yttria, has a porosity of 1% or less, has an average crystal particle diameter of 3 μm or smaller, has a cumulative frequency ratio measured by the following formula (1) of 3 or smaller, and has a dielectric loss tanδ of 1×10-4or lower at a frequency of 1-20 GHz. Wherein the cumulative frequency ratio= D90/D50 (1), and the meanings of each symbols in the formula (1) are as follows, D90: a crystal particle diameter (μm) at which the cumulative total from the smaller particle diameter side of the number-based particle size distribution of the crystal particles attains 90%, and D50: a crystal particle diameter (μm) at which the cumulative total from the smaller particle diameter side of the number-based particle size distribution of the crystal particles attains 50%. COPYRIGHT: (C)2010,JPO&INPIT