| 摘要 |
PROBLEM TO BE SOLVED: To produce a hexagonal boron nitride sintered body suitable for making a setter for firing large ceramics by forming a raw material mixture comprising a specific amount of highly fillable hexagonal boron nitride powder having a specific (surface-average diameter)/(50% volume cumulative particle size Dp50) ratio and a specified Dp50 and a specific amount of hexagonal boron nitride powder having a specific Dp50 value or less, and subsequently sintering the formed body. SOLUTION: Mixed powder comprising <=80 wt.% of highly fillable hexagonal boron nitride powder having a (surface-average diameter)/(Dp50) ratio of >=0.6 and a Dp50 of >=15 μm and >=20 wt.% of hexagonal boron nitride powder having a Dp50 of <=1.5 μm is used as raw material powder. The mixed powder is, if necessary, mixed with a sintering auxiliary and an organic binder, shaped, if necessary, defatted, and subsequently sintered in a non-oxidizing atmosphere. Since the raw material powder has excellent fillability, shape retainability and formability, a large molded product can be molded, and a sintered body having a largest length of >=450 mm can easily be produced. |
