Production manner null of high density boron nitride normal pressure sintering

摘要

PURPOSE:To enhance density and purity by blending hexagonal BN with B4C and B2O3 or H3BO3 in a specified weight ratio, molding the blend and sintering this molded body under ordinary pressure in an atmosphere of gaseous N2 or N-contg. nonoxidizing gas. CONSTITUTION:Cubic BN powder having 5-50m2/g specific surface area is wet- mixed with 5-20wt.% B4C and 0.1-16wt.% B2O3 or 0.1-16wt.% (expressed in terms of B2O3) H3BO3 in an org. solvent such as acetone. The resulting slurry is dried with a drying means such as a spray drier, granulated and molded into a prescribed shape by rubber press molding or other method under ordinary or elevated pressure. This molded body is sintered at 1,000-2,200 deg.C under ordinary pressure in an atmosphere of gaseous N2 or N-contg. nonoxidizing gas to obtain a high density and high strength ordinary pressure sintered body of BN.