Nitride coated piston ring

Patent metadata

Field	Value
Publication number	US-9829105-B2
Application number	US-201514490746-A
Country	US
Kind code	B2
Filing date	Jun 15, 2015
Priority date	Jun 15, 2015
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A piston ring and a method of forming a piston ring. A masking agent is applied to a selective area on an exterior surface of a piston ring. The masking agent inhibits the subsequent application of additional coatings to the selective area on the exterior surface of the piston ring. In one form, the masking agent may inhibit the subsequent application of a nitride layer to the selective area on the exterior surface of the piston ring. A recess may be formed in an outer peripheral side of the piston ring, and a thermal spray coating may be formed within the recess in the outer peripheral side of the piston ring.

First claim

We claim:

1. A method of forming a piston ring comprising:
providing a piston ring body formed of a base metallic material and having an upper lateral side, a lower lateral side, an outer peripheral side, an inner peripheral side, and first and second corners where the upper and lower lateral sides terminate into the outer peripheral side;
applying a masking agent to an entire exterior surface of the piston ring body;
removing a portion of the masking agent from a first selective area on the exterior surface of the piston ring body along the upper lateral side and the lower lateral side of the piston ring body to expose the base metallic material;
applying a nitride layer to the first selective area on the exterior surface of the piston ring body, wherein the remaining portion of the masking agent on the exterior surface of the piston ring body inhibits application of the nitride layer to areas on the exterior surface of the piston ring body other than the first selective area;
removing the masking agent from a second selective area along the outer peripheral side and along the first and second corners of the piston ring body to expose the base metallic material;
forming a recess in the outer peripheral side of the piston ring body; and
forming a thermal spray coating within the recess in the outer peripheral side of the piston ring body.

2. The method of claim 1 wherein the piston ring body is formed of stainless steel.

3. The method of claim 1 wherein the masking agent is applied to the entire exterior surface of the piston ring body by a two-step electro-chemical deposition process.

4. The method of claim 1 wherein the masking agent is applied to the entire exterior surface of the piston ring body by (i) depositing a first layer of nickel plating on the entire exterior surface of the piston ring body using an electrolytic deposition process, and then (ii) depositing a second layer of nickel plating over the first layer of nickel plating on the entire exterior surface of the piston ring body using an electro-less deposition process.

5. The method of claim 4 wherein the first layer of nickel plating is deposited on the entire exterior surface of the piston ring body at a first thickness and the second layer of nickel plating is deposited on the entire exterior surface of the piston ring body at a second thickness greater than the first thickness.

6. The method of claim 1 wherein the nitride layer is applied to the first selective area on the exterior surface of the piston ring body using a nitride diffusion process.

7. The method of claim 1 wherein the first corner of the piston ring body comprises an outer peripheral end portion of the upper lateral side and an upper end portion of the outer peripheral side, and the second corner of the piston ring body comprises an outer peripheral end portion of the lower lateral side and a lower end portion of the outer peripheral side, and wherein the nitride coating is not applied to the first and second corners of the piston ring body such that the base metallic material of the piston ring body is exposed along the outer peripheral end portions of the upper and lower lateral sides and along the upper and lower end portions of the outer peripheral side.

8. The method of claim 7 comprising: coating the upper and lower end portions of the outer peripheral side of the piston ring body with a chromium plating, a chromium-ceramic coating, or a HVOF coating.

Assignees

• Mahle Int Gmbh

Inventors

• Smith Thomas
• Bieneman Jason

Classifications

• C23C8/04

  Treatment of selected surface areas, e.g. using masks · CPC title

• C23C8/26

  of ferrous surfaces · CPC title

• F16J9/26 Primary

  characterised by the use of particular materials · CPC title

• Y10T29/49281

  including coating or plating · CPC title

• B23P15/06

  piston rings from one piece · CPC title