Alumina sintered body and method for manufacturing the same
AssigneeCoorstek Gk
InventorsTakuya Nakagawa, Yuji Fukasawa
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Abstract
An alumina sintered body having a low dielectric loss tangent and a method for manufacturing the alumina sintered body are provided. An alumina sintered body contains Al2O3 99.50 mass % or more, and 99.95 mass % or less and sodium and silicon, wherein at a surface layer A in any given cross-section and a central portion B of the cross-section in a depth direction from the surface layer A, a concentration ratio of sodium to silicon in the surface layer A is smaller than the concentration ratio of sodium to silicon at the central portion B.
Claims4
An alumina sintered body containing Al2O3 in an amount of 99.50 mass % or more, and 99.95 mass % or less, the alumina sintered body further containing sodium and silicon,
- wherein a dielectric loss tangent (a value of tan δ) at 4 GHz is 1×10−4 or less,
- wherein at a surface layer A in any given cross-section and at a central portion B of the cross-section in a depth direction from the surface layer A, a concentration ratio of sodium to silicon in the surface layer part A is smaller than the concentration ratio of sodium to silicon at the central portion B,
- wherein the concentration ratio of sodium to silicon of the alumina sintered body is 0.3 or less, and
- wherein the surface layer part A is within a range of 10 mm from a surface in the depth direction, and the central portion B is a region within a range of 10 mm in the depth direction centering at a center of the cross-section.
Dependencies are inferred from the claim text.