Patent ID: 8889252

Claim:
A cutting tool, comprising: a base material and a multi-layer coating formed on a surface of said base material, said multi-layer coating comprising an A-layer, a C-layer and a B-layer which are repeatedly deposited in an order of A-layer, C-layer and B-layer from the base material toward an outer surface of the multi-layer coating such that the B-layer is an uppermost layer of the multi-layer coating and the C-layer is a second uppermost layer of the multi-layer coating; the A-layer having a thickness of 0.5-2.0 μm and comprising a 1 layers having thicknesses of 4 nm-30 nm and comprising Ti 46-49 Al 51-54 N, and a 2 layers having thicknesses of 2 nm-25 nm and comprising Ti 34-38 Al 62-66 N, wherein a combined total of 8-20 layers of said a 1 layers and a 2 layers are non-periodically deposited per 100 nm; the B-layer having a thickness of 0.1 μm-0.5 μm and comprising Ti 34-38 Al 62-66 N; the C-layer having a thickness of 55-95 nm and comprising Ti 46-49 Al 51-54 N; wherein a thickness ratio of the B-layer to the A-layer in the multi-layer coating is less than 0.3, wherein the B-layer is at least 4.00 times as thick as any of the a 2 layers and the C-layer is at least 1.83 times as thick as any of the a 1 layers.