Titanium-nitride and titanium-carbide coated grinding tools and method therefor

Abstract

A titanium nitride coating (or equivalent metal or alloy) is applied over the abrasive surface of conventional CBN and diamond tools by the process of physical vapor deposition at temperatures below the tempering temperature of the core metal and below the temperature at which the difference between the coefficients of expansion of the substrate and of the abrasive causes stresses that damage the bond between them. Specific operating conditions are required during the deposition process in order to ensure the proper level of adhesion of the titanium nitride layer to the underlying material. Under these conditions, the process does not affect the integrity of the steel core of the grinding tool and the titanium nitride or equivalent coating stabilizes and reinforces the existing bond between the cubic boron nitride or diamond and the core, resulting in a grinding tool with greater efficiency and longer life. The titanium nitride layer provides a very hard coating with a low coefficient of friction that is well adhered to the underlying abrasive layer and to the layer providing the bond with the supporting substrate. As a result, during the grinding process the protective layer comes into contact with the work piece and prevents adhesion of the abrasive material with the work piece as well as loading up of the cutting surface with ground material.

Dependencies are inferred from the claim text.