Coated valve components with corrosion resistant sliding surfaces

Patent metadata

Field	Value
Publication number	US-11499643-B2
Application number	US-201816636519-A
Country	US
Kind code	B2
Filing date	Aug 6, 2018
Priority date	Aug 4, 2017
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

A valve component comprising a substrate with a sliding surface, the sliding surface being designed to be subjected to sliding against another surface during operation of the valve, wherein at least a portion of the sliding surface is coated with a coating comprising an under-layer comprising tungsten and an upper-layer deposited atop the under-layer, said upper-layer comprising diamond-like-carbon, wherein the under-layer comprises carbon and has a layer thickness of at least 11 micrometers, and the upper-layer has a lower coefficient of friction than the under-layer and has a layer thickness of at least 1.5 micrometers.

First claim

The invention claimed is:

1. A valve component comprising:
a substrate with at least one sliding surface, the sliding surface being designed to be subjected to sliding against another surface during operation of the valve, wherein at least a portion of the sliding surface is coated with a coating comprising an under-layer comprising tungsten and an upper-layer deposited atop the under-layer, said upper-layer comprising diamond-like-carbon, wherein
the under-layer comprises carbon and has a layer thickness between 20 and 30 micrometers,
and
the upper-layer has a lower coefficient of friction than the under-layer and has a layer thickness of at least 1.5 micrometers.

2. The valve component according to claim 1 , wherein the under-layer has a layer thickness of at least 12 micrometers.

3. The valve component according to claim 1 , wherein the under-layer comprises WC deposited by PVD sputtering of WC-targets in a vacuum chamber comprising argon and a carbon-containing gas.

4. The valve component according to claim 3 , wherein the carbon-containing gas is acetylene gas.

5. The valve component according to claim 1 , wherein:
between the coating and the sliding surface a Cr layer is deposited as an adhesion layer and the under-layer comprises:
a first-under-layer comprising Cr and WC, wherein the first-under-layer is formed having a multilayer structure comprising:
a first sub-layer deposited on the Cr adhesion layer, a second sub-layer deposited on the first sub-layer and a third sub-layer deposited on the second sub-layer,
wherein, if only Cr-content and WC-content in the first-under-layer are considered, then:
the first sub-layer is a gradient layer, exhibiting decreased average concentration of Cr and increased average concentration of WC along its thickness in a direction toward an outermost layer with an initial average concentration of Cr of 100 at % and an initial average concentration of WC of 0 at. %,
the second sub-layer is a layer with a constant average concentration of Cr and WC along its thickness, and
the third sub-layer is a gradient layer, exhibiting decreased average concentration of Cr and increased average concentration of WC along its thickness in a direction toward the outermost layer with a final average concentration of Cr of 0 at % and a final average concentration of WC of 100 at. %,

a second-under-layer deposited on the first-under-layer comprising WC+C or comprising WC+C+H,
a third-under-layer deposited on the second-under-layer deposited as a gradient layer, exhibiting decreased average concentration of WC along its layer thickness with a final average concentration of WC of 0 at. %, and
an upper layer of DLC.

6. A method for producing a valve component comprising a substrate with at least one sliding surface being designed to be subjected to sliding against another surface during operation of the valve, the method comprising:
coating at least a portion of the sliding surface with a coating, wherein the coating comprises an under-layer comprising tungsten and an upper-layer comprising diamond-like-carbon; and
depositing the upper-layer atop the under-layer, wherein the under-layer comprises carbon and has a layer thickness between 20 and 30 micrometers, and wherein the upper-layer has a lower coefficient of friction than the under-layer and has a layer thickness of at least 1.5 micrometers.

7. The method according to claim 6 , comprising using a PVD sputtering process for depositing the under-layer and using a PA-CVD or PVD sputtering or ARC evaporation or HIPIMS for depositing the upper-layer.

8. The method according to claim 6 , comprising depositing a Cr layer between the coating and the sliding surface as an adhesion layer, using a PVD sputtering process.

9. The method according to claim 8 ,
wherein the under-layer comprises:
a first-under-layer comprising Cr and WC, wherein the first-under-layer is formed having a multilayer structure comprising:
a first sub-layer deposited on the Cr adhesion layer, a second sub-layer deposited on the first sub-layer and a third sub-layer deposited on the second sub-layer,
wherein, if only Cr-content and WC-content in the first-under-layer are considered, then:
the first sub-layer is a gradient layer, exhibiting decreased average concentration of Cr and increased average concentration of WC along its thickness in a direction toward an outermost layer with an initial average concentration of Cr of 100 at % and an initial average concentration of WC of 0 at. %
the second sub-layer is a layer with a constant average concentration of Cr and WC along its thickness, and
the third sub-layer is a gradient layer, exhibiting decreased average concentration of Cr and increased average concentration of WC along its thickness in a direction to toward the outermost layer with a final average concentration of Cr of 0 at % and a final average concentration of WC of 100 at. %,

a second-under-layer deposited on the first-under-layer comprising WC+C or comprising WC+C+H,
a third-under-layer deposited on the second-under-layer deposited as a gradient layer, exhibiting decreased average concentration of WC along its layer thickness with a final average concentration of WC of 0 at. %, and
an upper layer of DLC,
wherein for the deposition of the Cr layer, Cr-targets are sputtered in an argon atmosphere, following the depositing of the first sub-layer, WC-targets are sputtered by increasing sputtering power continuously, while sputtering power continuously increases, sputtering power at the Cr-targets can be maintained constant,
wherein for depositing the second sub-layer, both the sputtering power of the Cr-targets and the WC-targets is maintained constant,
wherein for depositing the third sub-layer, the sputtering power at the Cr-targets is continuously reduced until disconnection of the Cr-targets, and the sputtering power at the WC-targets is maintained constant or increased continuously,
wherein for depositing the second-under-layer, acetylene gas is introduced in a coating chamber and maintained constant,
wherein for depositing the third-under-layer, the sputtering power at the WC-targets is reduced continuously until disconnection of the WC-targets, while a flow of the acetylene gas is increased as well as bias voltage is increased until a desired condition for depositing the DLC upper-layer is attained.

Assignees

• Oerlikon Surface Solutions Ag Pfaeffikon

Inventors

• Stadlberger Andreas
• Rovere Florian
• Jarry Olivier
• Wurzer Manfred
• Widowitz Franz

Classifications

• C23C14/0605

  Carbon · CPC title

• C23C28/341

  with at least one carbide layer · CPC title

• C23C28/044

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

• C23C28/046

  with at least one amorphous inorganic material layer, e.g. DLC, a-C:H, a-C:Me, the layer being doped or not · CPC title

• C23C14/025

  Metallic sublayers · CPC title