Beschichtetes Hartmetall-Schneidwerkzeug

摘要

The invention is to prolong the life time of tools dramatically by (1) considerably improving the flaking resistance of the coating layer at the time of cutting, (2) increasing the wear resistance and crater resistance of the coating layer itself, and (3) enhancing the breakage strength of the coating layer in comparison with the conventional coating cutting tools. In order to achieve the object, the coated cemented carbide of the invention has the following structure in the coating layer on the surface of the cemented carbides: The outer layer has an Al2O3 layer practically having an alpha-type crystal structure. The Al2O3 layer has a region where alpha-type and kappa-type crystal grains coexist in the first row of the crystal grains that grow on the inner layer. In addition to that, the crystal grains of alpha-Al2O3 in the region include no pores.