| 摘要 |
PROBLEM TO BE SOLVED: To produce a sintered compact having a high no-load Q-value and excellent thermal conductivity by a comparatively low temperature firing by adding a powder of a Li compound in addition to Mg, Ca and Si compounds as a sintering aid to Al2 O3 powder. SOLUTION: This alumina-based sintered compact is obtained by adding Mg, Ca, Si and Li compounds in a proportion of 0.005-0.1 wt.% of a Li compound expressed in terms of an oxide based on 100 wt.% of the total amount of the Mg, Ca, Si and Li compounds expressed in terms of the oxide to Al2 O3 powder containing <=0.07 wt.% of an Na component expressed in terms of the oxide, preferably no Na component, and firing the Al2 O3 with added compounds at 1520 deg.C so as to allow 35-40 wt.% of the Li component to remain in the sintered compact and so as to contain 0.002-0.04 wt.% of Li component expressed in terms of oxide based on 100 wt.% alumina-based sintered compact. The preferable composition of the sintered compact is 99.5-99.8 wt.% of the Al2 O3 , and 0.2-0.5 wt.% of the total of the Mg, Ca, Si and Li components expressed in terms of the oxide. The sintered compact has >=96% of a relative density and >=6,000 of a no-load Q-value. |
