HIGH-PRESSURE TYPE BORON NITRIDE-CONTAINING HIGH-HARDNESS HIGH-DENSITY COMPOSITE SINTERED COMPACT AND PRODUCTION THEREOF

摘要

PURPOSE:To allow the mass production of the high-pressure type boron nitride- contg. high-hardness high-density composite sintered compact and the production of large-sized members having intricate shapes by allowing the production of this sintered compact under sintering conditions of a relatively low pressure under which high-pressure type boron nitride is not in a thermodynamically stable region and a relatively low temp. CONSTITUTION:This high-pressure type boron nitride-contg. high-hardness high- density composite sintered compact and the process for production thereof consists in mixing high-pressure type boron nitride powder as it is or the coated high-pressure type boron nitride powder coated with a coating material and a raw material of a dense and high-hardness binder which is sintered under <2000MPa pressure and temp. not exceeding 1850 deg.C and has >=85% density and >=600 Vickers hardness and sintering such mixture for a proper period of time under the conditions of <2000MPa pressure and the temp. not exceeding 1580 deg.C under and at which the high-pressure type boron nitride is metastable.