A ZrO2—Al2O3 composite ceramic material
having high mechanical strength and toughness as well as excellent wear resistance
and hardness is provided. This ceramic material includes a first phase of ZrO2
grains containing 10 to 12 mol % of CeO2 as a stabilizer and having
an average grain size of 0.1 m to 1 m, and a second phase of Al2O3
grains having an average grain size of 0.1 to 0.5 m. The ceramic material
has a mutual nano-composite structure formed under a condition that a content of
the second phase in the ceramic material is within a range of 20 to 60 vol % such
that the Al2O3 grains are dispersed within said ZrO2
grains at a first dispersion ratio of 2% or more, and preferably 4% or more,
which is defined as a ratio of the number of the Al2O3 grains
dispersed within the ZrO2 grains relative to the number of the entire
Al2O3 grains dispersed in the ceramic material, and the ZrO2
grains are dispersed within the Al2O3 grains at a second
dispersion ratio of 1% or more, which is defined as a ratio of the number of the
ZrO2 grains dispersed within the Al2O3 grains
relative to the number of the entire ZrO2 grains dispersed in the ceramic material.