Patent ID: 6855413

Claim:
A cutting tool comprising: a body of sintered cemented carbide, cermet or ceramic; and a hard and wear resistant coating applied on at least a functioning portion of a surface of the body, wherein said coating comprises a structure of one or more refractory layers of which at least one layer consists essentially of an equiaxed fine grained κ-Al 2 O 3 with a thickness of 0.5-25 μm and with a grain size of less than 0.5 μm, and said fine grained κ-Al 2 O 3 layer comprises at least one sublayer with a thickness between 0.02 and 3 μm containing Al, Si and O with a Si concentration between 4-34 at %, Al concentration of greater than 0 to 37 at % and O concentration of 60-67 at %.