| 摘要 |
PROBLEM TO BE SOLVED: To obtain hexagonal baron nitride (h-BN) comprising fine grains and having a new shape by treating a fibrous compd. containing boron and nitrogen under specified conditions. SOLUTION: This h-BN powder comprising fine grains and having q new shape is a fine h-BN powder of grains each having a prolate spheroid-like or circular disk-like shape with the minor axial length a, major axial length Lb and thickness t satisfying 50 nm<=La<=Lb<=400, 20nm<=t<=150nm, t<=La, and 0.5<=La/Lb<=1.0. The powder is preferably a fine prolate spheroid-like or circular disk-like hexagonal boron nitride powder having layers of boron nitride hexagonal meshes deposited in the thickness direction. This fine prolate spheroid-like or circular disk-like h-BN powder is produced by heat treating a fibrous compd. containing boron and nitrogen in a nonacid gas atmosphere at 400 to 800±C, pulverizing the material, and then heat treating the pulverized material in a nonacid gas atmosphere at 1000 to 1800 deg.C.
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