BESCHICHTETE HARTLEGIERUNG

摘要

A coated hard metal employed for a cutting tool which is excellent in wear resistance and chipping resistance is provided. The coated hard metal is formed by providing a hard coating layer on a surface of a base material of cemented carbide or cermet. The hard coating layer includes an inner layer (2) which is formed on the base material (1) and consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti, an intermediate layer (3) which is formed on the inner layer (2) and consists of Al2O3 or ZrO2, and an outer layer (4) which is formed on the intermediate layer (3) and consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The thickness of the inner layer (2) is 0.1 to 5 mu m, the thickness of the intermediate layer (3) is 5 to 50 mu m in case of Al2O3 and 0.5 to 20 mu m in case of ZrO2, and the thickness of the outer layer (4) is 5 to 100 mu m.