Patent ID: 7442432

Claim:
Cutting tool insert comprising a substrate at least partially coated with a coating with a total thickness of from about 10 to about 40 μm of one or more refractory layers of which at least one layer is an alumina layer, said alumina layer being composed of columnar α-Al 2 O 3 grains with texture coefficients a) TC(104) greater than about 2.0; b) TC(012), TC(110), TC(113), TC(024) all less than about 1.0; c) TC(116) less than about 1.2; wherein the texture coefficient TC (hkl) is defined as TC ⁡ ( hk ⁢ ⁢ l ) = I ⁡ ( hk ⁢ ⁢ l ) I O ⁡ ( hk ⁢ ⁢ l ) ⁢ { 1 n ⁢ ∑ I ⁡ ( hk ⁢ ⁢ l ) I O ⁡ ( hk ⁢ ⁢ l ) } - 1 where I(hkl)=measured intensity of the (hkl) reflection I 0 (hkl)=standard intensity according to JCPDS card no 46-1212 n=number of reflections used in the calculation (hkl) reflections used are: (012), (104), (110), (113), (024), (116).