MOLDED BODY FOR PROCESSING METAL, HARD METAL, CERAMIC AND GLASS COMPRISING SINTERED BORON CARBIDE AND BONDED METAL PHASE AND HAVING HIGH HARDNESS AND HIGH TOUGHNESS AND ITS PRODUCTION

摘要

A molded, boron carbide-containing, sintered article which includes at least 65 percent by volume boron carbide; and from 5 to 35 percent by volume of at least one binder metal selected from the group consisting of molybdenum, molybdenum alloys, tungsten and tungsten alloys, having a melting point above 1,800 DEG C., and forming no molten borides or carbides within a temperature range of from 1,800 DEG to 1,950 DEG C. A method for producing the article includes the steps of mixing to obtain a homogeneous mixture from 20 to 80 percent by weight boron carbide particles having a particle size ranging from 1 to 1,650 microns with up to 80 percent by weight of particles of the at least one binder metal having a particle size ranging from 35 to 100 microns; introducing the homogeneous mixture into a graphite matrix mold; heating to sinter the homogeneous mixture at a temperature ranging from 1,800 DEG to 2,000 DEG C. for a predetermined heating time in a protective gas atmosphere to provide a sintered article; compressing the sintered article while hot in a protective gas atmosphere at a pressure ranging from 100 to 300 N/mm2 for a pressing time ranging from 5 to 20 minutes to provide the molded, sintered article; and cooling the molded, sintered article to ambient temperature at a cooling rate ranging from 100 DEG to 200 DEG C./min for a predetermined cooling time; provided that the sum of the heating time and the cooling time does not exceed the pressing time.