Patent ID: 10434580

Abstract:
A hard coating includes two first crystalline phases, and a second crystalline phase containing AlN of a wurtzite-type crystal structure disposed therebetween. The two first crystalline phases each include, independently, a laminate structure having a Ti1-x1Alx1N phase having a sodium chloride-type crystal structure, and an Alx2Ti1-x2N phase having a sodium chloride-type crystal structure that are alternately stacked. An Al composition ratio x1 satisfies a relationship 0.5≤x1≤0.75, and an Al composition ratio x2 satisfies a relationship 0.75<x2≤0.95. The laminate structure includes a region in which an Al concentration periodically changes along a stacking direction of the Ti1-x1Alx1N phase and the Alx2Ti1-x2N phase. In this region, a difference between a maximum value of the Al composition ratio x2 and a minimum value of the Al composition ratio x1 is greater than 0.25.