US 2006/0141271 A1 · Alumina layer with enhanced texture

Abstract

A refined method to produce textured α-Al2O3 layers in a temperature range of from about 750 to about 1000° C. with a controlled texture and substantially enhanced wear resistance and toughness than the prior art is disclosed. The α-Al2O3 layer is deposited 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 being composed of short pulses and purges consisting of Ti/Al-containing pulses and oxidizing pulses. The α-Al2O3 layer according to this invention has a thickness ranging from about 1 to about 20 μm and is composed of columnar grains. The length/width ratio of the alumina grains is from about 2 to about 12, preferably from about 5 to about 8. The layer is characterized by a strong (116) growth texture, measured using XRD, and by low intensity of (012), (110), (113) (024) and diffraction peaks.

Claims28

Dependent claims

Cutting tool insert of 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-Al2O3 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.
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
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).

57 more elements

Dependencies are inferred from the claim text.

Alumina layer with enhanced texture

Life of this patent

Alumina layer with enhanced texture

Life of this patent

Abstract

Claims28