Abstract: An improved process for the production of coated cemented carbide products is disclosed. A cemented carbide substrate is treated to form a metal carbide, nitride or carbonitride coating. The coated substrate is heat treated at a temperature close to or near the melting point of the binder metal of the cemented carbide to diffuse elements from the substrate into the coating. An intermediate (second) metal carbide, nitride or carbonitride coating is thereafter applied and the portion of the second is oxidized, nitrided or sulfided without detrimentally affecting the adherence of the second coating. Thereafter, a wear-resistant oxide (e.g., aluminum oxide) coating is applied to form the improved coated carbide product.

Abstract: An improved process for the production of coated cemented carbide products is disclosed. A cemented carbide substrate is treated to form a metal carbide, nitride or carbonitride coating. During the last part of this treatment or subsequent thereto, a sulfur-and/or nitrogen-containing gas is added to the atmosphere to form a sulfide-and/or nitride - containing layer on the coating. Thereafter, a wear-resistant oxide (e.g., aluminum oxide) coating is applied to form the improved coated cemented carbide product.