| 摘要 |
PROBLEM TO BE SOLVED: To provide an alumina ceramic sintered body having high strength and high hardness at room temperature and a high temperatures, its manufactur ing method and a cutting tool having suitability for high-speed cutting and resistance to chipping. SOLUTION: The sintered body is obtained by preparing a mixture of raw material powders containing alumina and a 3A-group metal oxide or a 3A-group metal compound which is to be converted into a 3A-group metal oxide by heating, and firing the mixture. In the sintered body, an average particle diameter of alumina particles is <=4.0 μm and the total amount of alkali metal, alkaline earth metal, Si and Ti elements vs. 100 mol of alumina is <=0.1 mol. The ratio of the total of the maximum peak strengths of ReAlO3 and Re3 Al5 O12 (Re: 3A-group metal) vs. the maximum peak strength of alumina determined by X-ray diffraction method is 1-75% and the relative density vs. the theoretical density is >=99.0%. |
