Coating sintered hard alloy with titanium carbide - by titanium diffusion from pack contg. titanium carbide as filler

摘要

A wear resistant titanium carbide coating is applied to a sintered hard alloy by diffusion of titanium into the article at 950-1100 deg.C in a hydrogen atmos. using a powder-mixt. comprising (by wt.) 20-60% Ti, 40-80% TiC as filler and 1-5% NH4Cl as activator. The method is useful for forming wear resistant coatings on multi-facet cemented carbide throwaway tips for machining metals. Use of TiC instead of Al2O3 as filler results in 6-18 microns thick coatings of hardness 2500-2700 kg/sq. mm. which improve the wear resistance of the tips by 4-6 times when used for machining iron and steel. Additionally, coating formation rate is increased to 10-15 microns/hr., so that no special sealed containers are required for the process, and the resulting coating is smooth and has a uniform compsn.