| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an alumina sintered compact in which a dielectric dissipation factor in MHz to GHz can be reduced, and which has high strength as well. <P>SOLUTION: The alumina sintered compact comprises, as an element, Al by ≥99.3 mass% expressed in terms of Al<SB>2</SB>O<SB>3</SB>and comprises, as the other elements, Si and M (M denotes at least one kind selected from Mg, Ca, Sr and Ba). The alumina sintered compact has a structure where alumina crystal grains exist as the main crystal grains, the average grain size of the alumina crystal grains is ≥20 μm in volumetric distribution on the average, and further, a plurality of small-sized grains 2 made of the alumina crystal grains with a grain size of ≤5 μm are aggregated at a triple point R composed of large-sized grains 1 made of alumina crystal grains with a grain size of ≥10 μm, and a compound expressed by MAl<SB>2</SB>Si<SB>2</SB>O<SB>8</SB>is present at the triple point R. <P>COPYRIGHT: (C)2011,JPO&INPIT |
