Patent ID: 8323783

Claim:
A coated cutting insert comprising: a substrate; and a multilayer coating scheme comprising: an α-Al 2 O 3 layer; and an outer layer of ZrCN or HfCN on the α-Al 2 O 3 layer, wherein the outer layer exhibits a blasted stress condition ranging between about −700 MPa to about −4.0 GPa as measured by XRD using the Psi tilt method and the (220) reflection of ZrCN or HfCN and a bonding layer between the α-Al 2 O 3 layer and the outer layer, the bonding layer comprising M(O x C y N z ) wherein M is selected from the group comprising one or more of the following titanium, hafnium, zirconium, chromium, titanium-aluminum alloy, hafnium-aluminum alloy, zirconium-aluminum alloy, chromium-aluminum alloy, and their alloys, and x≧0, y≧0, z≧0 and y+z>0, and whereby when M is aluminum, then at least one of titanium, hafnium, zirconium or chromium is also present.