| 摘要 |
PROBLEM TO BE SOLVED: To provide alumina ceramic having high purity, denseness and machinability by using specific Al2 O3 powder containing Y2 O3 as a raw material and applying a specified firing condition. SOLUTION: This alumina ceramic uses the raw materials consisting of 99.05-99.85wt.% Al2 O3 , 0.01-0.10wt.% MgO, 0.05-0.50wt.% SiO2 , and 0.05-0.50wt.% Y2 O3 and also uses the raw material powder being 0.4-1.0μm average particle diameter of Al2 O3 powder and having >=5m<2> /g BET specific surface area and is produced by maintaining the max. temp. of the firing in the range of 1,550-1,650 deg.C at least for one hour or more. This sintered compact has >=3.85g/cm<3> Archimedes density, 5-20μm average particle diameter, <=1,500kgf/ mm<2> Vickers hardness and >=370MPa elastic modulus. |
