Coated cutting tool

Patent metadata

Field	Value
Publication number	US-9334561-B2
Application number	US-201314380962-A
Country	US
Kind code	B2
Filing date	Feb 26, 2013
Priority date	Feb 29, 2012
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

The present invention relates to a coated cutting tool comprising a substrate and a multilayered (Ti,Al)N coating. The coating comprises three zones: a first zone (A) closest to the substrate, a second zone (B) adjacent to the first zone and a third outermost zone (C). All three zones each comprises a multilayered aperiodic structure of (Ti,Al)N, where the average composition for each zone is different from each other and where the ratio between the thickness of the zone C and zone B is between 1.3 and 2.2 and where z zone C >Z zone B , where z is the average composition for each zone of the ratio z=Ti/Al. The coating has a low residual stress.

First claim

The invention claimed is:

1. A coated cutting tool comprising:
a substrate; and
a multilayered (Ti,Al)N coating, wherein the coating includes three zones: a first zone (A) closest to the substrate, a second zone (B) adjacent to the first zone and a third outermost zone (C) the second and third zones B and C each having a multilayered aperiodic structure of alternating individual (Ti,Al)N layers X and Y, wherein an individual layer X has a composition with a higher Ti-content than an individual layer Y, the individual layer X having a composition of Ti a Al 1-a N, where 70<a<90, and the individual layer Y having a composition of Ti b Al 1-b N, where 33<b<40, the average composition for each zone being different from each other and a ratio between the thickness of zone C and zone B is between 1.3 and 2.2 and where z zone C >Z zone B , where z is the average composition for each zone of the ratio z=Ti/Al.

2. A coated cutting tool according to claim 1 , wherein the individual layer X has a composition of Ti a Al 1-a N, where 70≦a≦80 and the individual layer Y has a composition of Ti b Al 1-b N, where 34≦b≦39.

3. A coated cutting tool according to claim 1 , wherein the thickness of the sum of ten consecutive individual layers in the aperiodic structure is smaller than 300 nm.

4. A coated cutting tool according to claim 1 , wherein a compressive residual stress is between −0.5 to −1.5 GPa.

5. A coated cutting tool according to claim 1 , wherein the ratio between the thickness of the zone C and zone B is between 1.4 and 1.9.

6. A coated cutting tool according to claim 1 , wherein the first zone is a homogenous (Ti,Al)N layer having a composition of Ti a Al 1-a N, where 70≦a≦90.

7. A coated cutting tool according to claim 1 , wherein zones B and C each comprise a multilayered aperiodic structure of alternating (Ti,Al)N layers X and Y.

8. A method of making a coated cutting tool comprising the steps of:
providing substrates to be coated;
placing the substrates in a deposition chamber having a total of 6 flanges each flange including at least one (Ti,Al)-target, wherein 3 of the flanges include targets having a composition X and the other 3 flanges include targets having a composition Y, where composition X has a higher Ti-content than composition Y;
depositing the substrates in a first deposition step, wherein the targets having composition X are active in the presence of nitrogen gas and at a bias of between 100 to 200 V;
depositing the substrates in a second deposition step, wherein the targets of all 6 flanges are active in the presence of nitrogen gas and at a bias of between 30 to 60 V; and
depositing the substrates in a third deposition step, wherein one of the flanges having targets having composition Y is turned off leaving the remaining targets active in the presence of nitrogen gas and at a bias of between 30 to 60 V.

9. A method of making a coated cutting tool according to claim 8 , wherein the target X has a composition of Ti a Al 1-a N, where 70≦a≦90, and the target Y has a composition of Ti b Al 1-b N, where 33≦b≦40.

10. A method of making a coated cutting tool according to claim 8 , wherein the target X has a composition of Ti a Al 1-a N, where 70≦a≦80, and the target Y has a composition of Ti b Al 1-b N, where 34<b<39.

11. A method of making a coated cutting tool according to claim 8 , wherein the deposition is continuous.

Assignees

• Sandvik Intellectual Property

Inventors

• Ericsson Bjorn

Classifications

• C23C14/0641 Primary

  Nitrides (C23C14/0617 takes precedence) · CPC title

• C23C28/42

  characterized by the composition of the alternating layers · CPC title

• C23C30/005

  on hard metal substrates · CPC title

• C23C28/044

  coatings specially adapted for cutting tools or wear applications · CPC title

• C23C28/042

  including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides · CPC title