| 摘要 |
PURPOSE:To provide a sintered compact for tool capable of low-temp. sintering an causing neither breaking nor abnormal wear of tip at the time of high-speed cutting by adding specific amounts of monoclinic ZrO2 having specific grain size to Al2O3. CONSTITUTION:This sintered compact for tool is produced by sintering a powder mixture consisting of 1-10wt.% monoclinic ZrO2 having <=1000Angstrom average grain size and 90-99wt.% Al2O3. Since ZrO2 enables the low-temp. sintering of Al2O3 and is uniformly dispersed in the surface of Al2O3 grains, and further, at the time of sintering, ZrO2 absorbs impurity components in Al2O3 and also forms solid solutions together with Al2O3, the grain boundaries are firmly bound. Moreover, when the average grain size of ZrO2 is >=1000Angstrom , uniform dispersion into Al2O3 grains cannot be attained, and further, when the additive quantity of ZrO2 is less than 1%, grain boundary binding power is insufficient, and, on the other hand, the effect caused by increased amount of ZrO2 cannot be produced when it exceeds 10%. The above sintered compact can be attained even by normal pressure sintering in the air and can show superior characteristics, e.g. in high-speed matching of steel in particular. |
