MANUFACTURE OF SURFACE-COATED TUNGSTEN CARBIDE BASE CEMENTED CARBIDE CUTTING TOOL

摘要

PURPOSE: To develop an excellent cutting capability for long time by mixing a nitrogen oxide gas with a hydrogen-carbon dioxide-aluminum chloride base mixed gas used as a reaction gas at a specified rate % by volume when an aluminum oxide layer is formed. CONSTITUTION: A hard coating layer of an averaged layer thickness of usually approx. 3 to 30μm is formed laminatedly with one or more types of Ti carbon.nitrogen oxide layers and an Al2 O3 layer on the surface of a tungsten carbide base cemented carbide base body, using a chemical vapor deposition method and/or physical deposition method so as to manufacture a coated cemented carbide cutting tool. To form the Al2 O3 layer, NOx gas is mixed with a hydrogen-carbon dioxide-aluminum chloride base mixed gas used as reaction gas at a mixing rate of 0.1 to 1% by volume, desirably 0.3 to 0.6 % by volume of all NOx gas. Thus the adhesiveness of the formed Al2 O3 layer to the Ti carbon.nitrogen oxide layers can be increased.