Enhanced alumina layer with texture
AssigneeSeco Tools AB
InventorSakari Ruppi
Life of this patent
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Abstract
A refined method to produce textured α-Al2O3 layers in a temperature range of 750-1000° C. with a controlled texture and substantially enhanced wear resistance and toughness than the prior art is disclosed. The α-Al2O3 layer is formed on a bonding layer of (Ti,Al)(C,O,N) with increasing aluminium content towards the outer surface. Nucleation of α-Al2O3 is obtained through a nucleation step composed of short pulses and purges of Ti-containing and oxidizing steps. The α-Al2O3 layer has a thickness ranging from 1 to 20 μm and is composed of columnar grains. The length/width ratio of the alumina grains is from 2 to 15, preferably 6 to 10. The layer is characterized by a strong (110) growth texture, measured using XRD, and by the low intensity of (012), (104), (113), (024) and (116) diffraction peaks.
Claims18
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 wherein said alumina layer is composed of columnar α-Al2O3 grains with texture coefficients
- a) TC(110) greater than about 2.0;
- and
- b) TC(012), TC(104), TC(113), TC(024), TC(116) all less than about 1.5;
- wherein the texture coefficient TC(hkl) is defined as
- TC
-
- (
- hkl
- )
- =
- I
-
- (
- hkl
- )
- I
- o
-
- (
- hkl
- )
-
- {
- 1
- n
-
- ∑
- I
-
- (
- hkl
- )
- I
- o
-
- (
- hkl
- )
- }
- -
- 1
- where
- I(hkl)=measured intensity of the (hkl) reflection
- IO(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).
Dependencies are inferred from the claim text.