Patent ID: 7455900

Claim:
Cutting tool insert comprising a substrate at least partially coated with a coating with a total thickness of from 10 to about 40 μm of one or more refractory layers of which at least one layer is an alumina layer wherein said alumina layer is composed of columnar α-Al 2 O 3 grains with texture coefficients a) TC(116) greater than about 1.8 b) TC(012), TC(104), TC(110), TC(113), TC(024) all less than about 1.5. wherein the texture coefficient TC(hkl) being defined as TC ⁡ ( hk ⁢ ⁢ 1 ) = I ⁡ ( hk ⁢ ⁢ 1 ) I o ⁡ ( hk ⁢ ⁢ 1 ) ⁢ { 1 n ⁢ ∑ I ⁡ ( hk ⁢ ⁢ 1 ) I O ⁡ ( hk ⁢ ⁢ 1 ) } - 1 where I (hkl)=measured intensity of the (hkl) reflection I O (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).