Production manner null of big boron nitride normal pressure sintering body

摘要

PURPOSE:To improve lubricating properties and mold release characteristics, by preferably specifying specific surface area and normal-pressure sintering temperature of boron nitride powder and calcining a molded article consisting essentially of boron nitride having given Shore hardness. CONSTITUTION:Powder comprising =90wt.% boron nitride (e.g., BN of hexagonal system having 99.0% purity and 90m2/g specific surface area) having preferably 30-200m2/g specific surface area and 30-60 Shore hardness is molded by a mold under, for example, 2ton/cm2 pressure. Then, the molded article is molded in a nitrogen-containing nonoxidizing atmosphere (e.g., 10% nitrogen) at 400-1,400 deg.C (e.g., 1,000 deg.C) (for 3hr).