GB376299A - Method of making hard alloys for cutting tools - Google Patents

Abstract

Tantalum carbide may be made by preheating lampblack or charcoal in a closed graphite crucible to 1500 DEG C. to remove organic impurities and gases, mixing it with tantalum powder in about the proportion of 5-6,2 per cent of carbon and 93,8-95 per cent of tantalum, and slowly heating the mixture in a highfrequency furnace to about 2000 DEG C. The product is ground and heated to 1600-1700 DEG C. in a vacuum furnace.ALSO:In the production of alloys by pressing and heat treatment of a powdered mixture of a refractory metal such as tantalum, niobium, molybdenum, or tungsten, a non-metal such as carbon or boron, and a metal of the iron group, the heat treatment of the compound of the refractory metal and the non-metal prior to admixture with the iron-group metal, or of the final mixture, or both, is carried out in a vacuum to degasefy the product and prevent the absorption of oxygen. The mixture may be pressed cold at a pressure of several tons per square inch before the heat treatment in a vacuum. For example tantalum carbide may be made by preheating lampblack or charcoal in a closed graphite crucible to 1500 DEG C. to remove organic impurities and gases, mixing it with tantalum powder in about the proportion of 5-6,2 per cent of carbon and 93,8-95 per cent of tantalum, and slowly heating the mixture in a high-frequency furnace to about 2000 DEG C. The product is ground and heated to 1600-1700 DEG C. in a vacuum furnace, and is then mixed with 3-15 per cent of hydrogen-reduced nickel powder, or a mixture of nickel and iron, and again ground, pressed, and heated in a vacuum.