| 摘要 |
PURPOSE:To improve wear resistance by bringing the surface of a powder molding essentially consisting of Al2O3 powder into contact with a compd. contg. groups 3a to 6a elements of periodic table and >=1 kinds among Fe, Ni, Co and Si, then sintering the molding. CONSTITUTION:The powder molding essentially consisting of the alpha-Al2O3 is brought into contact with the compd. contg. the groups 3a to 6a elements of periodic table such as NiCl2, and >=1 kinds among Fe, Ni, Co and Si or is impregnated into a precursor soln. of the compd. The molding is then calcined at 1400 to 1800 deg.C in an atmosphere gas, such as gaseous mixture composed of NiCl2/N2, by which the alumina sintered body having a surface tempered layer of 0.05 to 3.00mm thickness is obtd. This sintered body consists of >=50wt.% alpha-Al2O3 which is internally granular, planar or fibrous and the balance >=1 kinds among MgO, Y2O3 and Cr2O3. The surface tempered layer thereof has the structure in which the diffusion elements of the groups 3a to 6a elements of periodic table and >=1 kinds among the Fe, Ni, Co and Si decrease gradually from the surface to the inside. The alumina sintered body for tools having the excellent wear resistance is thus obtd. |
