| 摘要 |
PROBLEM TO BE SOLVED: To provide: a ceramic sintered body that is excellent in corrosion resistance against an alkaline composition of compositions composing a positive electrode material of a lithium ion secondary battery and thermal shock resistance; a member for heat treatment using the same.SOLUTION: A ceramic sintered body of this invention is a ceramic sintered body that includes: exceeding 50 mass% and at most 93 mass% of magnesium oxide; and at least 7 mass% and less than 50 mass% of a metallic acid magnesium, wherein, in an observation region where the ceramic sintered body is observed in a cross-sectional view, an area ratio of a crystal of the magnesium oxide having a crystal grain size of at most 0.3 mm is at least 55 area%, and an area ratio of a crystal of the metallic acid magnesium having a crystal grain size of at least 0.5 mm is at least 4 area%. By the configuration, a lot of fine crystals of the magnesium oxide exist, thereby anticorrosion becomes high, the magnesium oxide is easily located between large crystals of the metallic acid magnesium, rising of a coefficient of linear expansion is suppressed, thereby thermal shock resistance becomes high, and anticorrosion and thermal shock resistance can be combined. |
