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Method of coating a body with an α-alumina coating

Assignee: Sandvik Intellectual Property AB
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Filing: 1995-09-22
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Granted: 1997-08-05
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Expires: 2015-09-22
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Abstract

Abstract A method of coating a body coated with refractory single- or multi-layers, wherein specific layers are characterized by a controlled microstructure and phase composition with crystal planes preferably grown in a preferential direction with respect to the surface of the coated body. The coating comprises one or several refractory layers of which at least one layer is a dense, fine-grained layer of alpha -Al2O3 preferably textured in the (012) direction. The coated tool according to the present invention exhibits excellent surface finish and shows much improved wear and toughness properties compared to prior art objects when used for machining steel, cast iron and, particularly, when machining nodular cast iron.

Inventors

  • 👤 Bjorn Ljungberg
  • 👤 Anders Lenander

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 01:52
CPC Classifications
C; C23; C23C; C23C30/00; C23C30/005; C23C16/00; C23C16/22; C23C16/30; C23C16/40; C23C16/403; C23C16/02; C23C16/0272; Y; Y10; Y10T; Y10T407/00; Y10T407/27

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 100 words
A method of coating a cutting tool body with an α-alumina coating consisting essentially of heating the cutting tool body while bringing the cutting tool body in contact with a hydrogen carrier gas to which has been added CO 2 , followed by CO, and than AlCl 3 so as to deposit an alpha-alumina layer on the cutting tool body, wherein the oxidation potential of the hydrogen carrier gas is controlled by maintaining a content of H 2 O in the carrier gas below 20 ppm of H 2 O prior to nucleation of said alpha-Al 2 O 3 .
Claim 2
Independent Claim 100 words
A method of coating a cutting tool body with an α-alumina coating consisting essentially of heating the cutting tool body while bringing the cutting tool body in contact with a hydrogen carrier gas to which has been added CO 2 , followed by CO, and than AlCl 3 so as to deposit an alpha-alumina layer on the cutting tool body, wherein the oxidation potential of the hydrogen carrier gas is controlled by maintaining a content of H 2 O in the carrier gas below 20 ppm of H 2 O prior to nucleation of said alpha-Al 2 O 3 .
Claim 3
Dependent Claim 47 words
The method of claim 1, wherein the H 2 O content of the hydrogen carrier gas is below 5 ppm of H 2 O prior to the nucleation of the alpha-Al 2 O 3 and the nucleation is carried out at a temperature of about 1000° C.
Claim 4
Dependent Claim 39 words
The method of claim 1, wherein the alpha-alumina layer has a thickness (d) of 0.5-25 μm and a single phase α-structure with a grain size (s): 0.5 μm<s<1 μm for 0.5μ<d<2.5 μm and 0.5 μm<s<3 μm for 2.5μ<d<25 μm.
Claim 5
Dependent Claim 28 words
The method of claim 1, wherein the surface roughness (R a ) of the alpha-alumina layer is less than 0.3 μm over a measured length of 0.25 mm.
Claim 6
Dependent Claim 65 words
The method of claim 1, wherein the alpha-alumina layer exhibits a texture coefficient TC greater than 1.3 for the (012) growth direction of the equivalent crystallographic planes defined as: ##EQU2## where I(hkl)=measured intensity of the (hkl) reflection o (hkl)=standard intensity of the ASTM standard powder pattern diffraction data n=number of reflections used in the calculation, (hkl) reflections used are: (012), (104), (110), (113), (024), (116).
Claim 7
Dependent Claim 15 words
The method of claim 5, wherein the texture coefficient TC (012) is greater than 1.5.
Claim 8
Dependent Claim 32 words
The method of claim 1, wherein the cutting tool body includes an intermediate layer of a metal carbide, metal nitride or metal carbonitride, the alpha-alumina layer being deposited on the intermediate layer.
Claim 9
Dependent Claim 25 words
The method of claim 1, wherein the cutting tool body includes an intermediate layer of TiCN, the alpha-alumina layer being deposited on the intermediate layer.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2000-08-04 2001-02-03 2001-08-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-08-04 2005-02-03 2005-08-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-08-04 2009-02-03 2009-08-05 $7700.00 Window Closed / Lapsed

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