| 摘要 |
<p>A sintered body containing alumina crystal particles and zirconia crystal particles as main components includes the tetragonal crystal particles as the zirconia crystal particles. The zirconia crystal particles satisfy relations 0%‰¤A‰¤ 3%, 3%‰¤ B‰¤22% and 77%‰¤ C ‰¤96%. A represents a ratio of a number a of first zirconia crystal particles to the total number N of the zirconia crystal particles, wherein each of the first zirconia crystal particles is surrounded by only the zirconia crystal particles. B represents a ratio of a number b of second zirconia crystal particles to the total number N of the zirconia crystal particles, wherein each of the second zirconia crystal particles is surrounded by only the alumina crystal particles. C represents a ratio of a number c of third zirconia crystal particles to the total number N of the zirconia crystal particles, wherein each of the third zirconia crystal particles is surrounded by both the zirconia crystal particle and the alumina crystal particle. N represents a total number of the zirconia crystal particles in a 10 µm square area at any cut plane of the sintered body. The number N is equal to or greater than a value 140.</p> |
