| 摘要 |
PROBLEM TO BE SOLVED: To produce boron nitride flocs having a density, which is nearly equal to a mean density attained through a hot pressing by a method wherein one or more stages of cold pressing and granulating operations of boron nitride particles prepared by crushing a high purity hexagonal system boron nitride into particles each having a specified particle diameter are executed. SOLUTION: A high purity hexagonal system boron nitride is crushed into boron nitride particles, which have the range of the particle diameter of at least 100μm and the major portion of which has a particle diameter exceeding 50μm. The crushed particles are cold-pressed into a compressed state and the compressed particles are granulated into a granular powder. Further, through a method containing one or more stages of cold pressing and granulating operations so as to turn the granules into ones having the size suitable for the use of a filling material having a high heat conductivity, boron nitride flocs, each having a high density and the high heat conductivity are formed from a cold-pressed hexagonal system boron nitride.
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