Patent ID: 7012036

Claim:
A method of producing a ZrO 2 —Al 2 O 3 composite ceramic material, said composite ceramic material comprising: a first phase of ZrO 2 grains containing 10 to 12 mol % of CeO 2 as a stabilizer and having an average grain size of 0.1 μm to 1 μm, said ZrO 2 grains composed of 90 vol % or more of tetragonal ZrO 2 ; a second phase of Al 2 O 3 grains having an average grain size of 0.1 to 0.5 μm; wherein said Al 2 O 3 grains are dispersed within said ZrO 2 grains at a first dispersion ratio of 4% or more, which is defined as a ratio of the number of said Al 2 O 3 grains dispersed within said ZrO 2 grains relative to the number of the entire Al 2 O 3 grains dispersed in the composite ceramic material, and said ZrO 2 grains are dispersed within said Al 2 O 3 grains at a second dispersion ratio of 1% or more, which is defined as a ratio of the number of said ZrO 2 grains dispersed within said Al 2 O 3 grains relative to the number of the entire ZrO 2 grains dispersed in the composite ceramic material, wherein the method comprises: mixing an α-Al 2 O 3 powder having an average particle size of 0.3 μm or less with a γ-Al 2 O 3 powder having a specific surface within a range of 10 to 100 m 2/ g and a substantially spherical shape prepared such that a mixture ratio by volume of the γ-Al 2 O 3 powder to the α-Al 2 O 3 powder is in a range of 50:50 to 90:10, thereby obtaining a second powder for providing said Al 2 O 3 grains; mixing a first powder for providing said ZrO 2 grains with the second powder; molding a resultant mixture in a desired shape to obtain a green compact, and sintering said green compact at a sintering temperature in an oxygen-containing atmosphere.