Abstract: A ZrO2—Al2O3-based ceramic sintered compact containing tetragonal ZrO2 particles having a crystallite size of from 5 to 20 nm as a main component and having an ?-Al2O3 crystallite size of not greater than 75 nm and a relative density of not less than 99% can be produced by preparing a Y2O3 partially stabilized ZrO2—Al2O3-based powder having a molar ratio (mol %) of zirconia (ZrO2) and yttria (Y2O3) of from 96.5:3.5 to 97.5:2.5 and a mass ratio (mass %) of ZrO2 containing Y2O3 and alumina (Al2O3) of from 85:15 to 75:25, molding this powder by cold isostatic pressing, and then performing sintering to a high density by microwave sintering for 45 to 90 min in an inert gas atmosphere at 1200 to 1400° C. When performing microwave sintering, a heating rate is preferably from 5 to 20° C./min up to 600° C. and from 50 to 150° C./min at 600° C. or higher.

Abstract: A ZrO2—Al2O3-based ceramic sintered compact containing tetragonal ZrO2 particles having a crystallite size of from 5 to 20 nm as a main component and having an ?-Al2O3 crystallite size of not greater than 75 nm and a relative density of not less than 99% can be produced by preparing a Y2O3 partially stabilized ZrO2—Al2O3-based powder having a molar ratio (mol %) of zirconia (ZrO2) and yttria (Y2O3) of from 96.5:3.5 to 97.5:2.5 and a mass ratio (mass %) of ZrO2 containing Y2O3 and alumina (Al2O3) of from 85:15 to 75:25, molding this powder by cold isostatic pressing, and then performing sintering to a high density by microwave sintering for 45 to 90 min in an inert gas atmosphere at 1200 to 1400° C. When performing microwave sintering, a heating rate is preferably from 5 to 20° C./min up to 600° C. and from 50 to 150° C./min at 600° C. or higher.