Process for applying a wear-resistant titanium carbide or titanium carbonitride coating to workpieces made of sintered hard alloys

摘要

Process for the chemical and thermal treatment of metals and alloys which can be used in machine construction and metal treatment operations in order to increase the service life of metal coatings, in particular a process for applying a wear-resistant coating of titanium carbide or titanium carbonitride to workpieces made of sintered hard alloys with the composition WC-Co, WC-TiC-Co or WC- TiC-TaC-Co. The essential feature is that the workpiece is treated in a closed reactor at a pressure of between 1.3 x 10(-3) Pa and 1.3 x 10(2) Pa at a temperature of 1100-1250 degrees C. The workpiece is first treated with a hydrocarbon- containing gas, such as methane, and then with titanium chloride. The latter is prepared by treating metallic titanium, which is placed in the reactor with the workpiece, with carbon tetrachloride. The workpiece, now coated with titanium carbide, is again treated with a gas containing a hydrocarbon or nitrogen, e.g. nitrogen gas itself. The process can be used in industry when making hard alloy components and in the machine construction sector where hard alloys are used for making tools intended for machining objects made of metals or alloys.