Piston ring having a wear protection layer containing particles, method for production and use

Patent metadata

Field	Value
Publication number	US-12504074-B2
Application number	US-202218694045-A
Country	US
Kind code	B2
Filing date	Sep 28, 2022
Priority date	Sep 30, 2021
Publication date	Dec 23, 2025
Grant date	Dec 23, 2025

Abstract

A piston ring for internal combustion engines is provided, having a surface comprising a wear protection layer of iron or an iron alloy applied to the surface, wherein the wear protection layer has cracks and the cracks have an average density of 10-160 cracks per mm of the wear protection layer, wherein the iron or iron alloy have incorporated therein 0.2-15% by weight, based on the total weight of the wear protection layer, of carbon particles and 0.2-15% by weight, based on the total weight of the wear protection layer, of solid particles other than carbon particles. Furthermore, a method for manufacturing a piston ring is provided.

First claim

What is claimed is:

1 . A piston ring for an internal combustion engine, comprising a wear protection layer of iron or an iron alloy applied to a surface of the piston ring, wherein the wear protection layer has cracks and the cracks have an average density of 10-160 cracks per mm of the wear protection layer, wherein 0.2-15% by weight, based on the total weight of the wear protection layer, of carbon particles and 0.2-15% by weight, based on the total weight of the wear protection layer, of solid particles which are a different type of particle than the carbon particles are embedded in the iron or the iron alloy of the wear protection layer.

2 . The piston ring according to claim 1 , wherein a proportion of the carbon particles and/or the solid particles, that are a different type of particle than the carbon particles, located in the cracks, relative to a total number of particles, in the wear protection layer is <0.1% in each case.

3 . The piston ring according to claim 1 , wherein a proportion of the sum of the carbon particles and solid particles, which are a different type of particle than the carbon particles, which is located in the cracks is <0.05% in relation to a total number of particles in the wear protection layer.

4 . The piston ring according to claim 1 , wherein the carbon particles are partially converted into iron-carbon compounds.

5 . The piston ring according to claim 1 , wherein the average density of the cracks is from 30 to 120 cracks per mm of the wear protection layer.

6 . The piston ring according to claim 1 , wherein the cracks have an average width of 0.05-1.5 μm.

7 . The piston ring according to claim 1 , wherein the carbon particles and/or the solid particles, which are a different type of particle than the carbon particles, each have an average particle size of 0.05-3 pm independently of one another.

8 . The piston ring according to claim 1 , wherein the carbon particles are made of diamond and/or graphite and/or the solid particles, which are a different type of particle than the carbon particles, are made of tungsten carbide, chromium carbide, aluminum oxide, silicon carbide, silicon nitride, boron carbide and/or cubic boron nitride.

9 . The piston ring according to claim 1 , wherein the solid particles, which are a different type of particle than the carbon particles, are made of cubic boron nitride.

10 . The piston ring according to claim 1 , wherein the iron alloy comprises ≥90% by weight of iron, based on the total weight of the iron alloy.

11 . The method of manufacturing the piston ring according to claim 1 , comprising the steps of:
(a) placing the piston ring in an aqueous electrolyte containing:
an iron (II) compound in an amount corresponding to 100-500 g/l FeCl 2 ,
the carbon particles,
the solid particles, which are a different type of particle than the carbon particles, and
optionally a salt of a further metal,
wherein a pH of the aqueous electrolyte is <0, then (b) galvanically depositing the wear protection layer of iron or iron alloy on the piston ring at a cathodic current density of 10-80 A/dm 2 , then (c) drying the piston ring with wear protection layer, and then (d) is heated heating the piston ring to 300-700° C.

12 . The method according to claim 11 , wherein a pH value of the aqueous electrolyte is ≤−0.1.

13 . The method according to claim 11 , wherein after step (b) a current direction is reversed, wherein an anodic current density is 1-30 A/dm 2 , then the current direction is reversed again and step (b) is carried out again.

Assignees

• Fed Mogul Burscheid Gmbh

Inventors

• Dürdoth Stefan
• Distelrath-Lübeck Anika

Classifications

• C25D7/04

  Tubes; Rings; Hollow bodies · CPC title

• C25D15/00

  Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires · CPC title

• C25D5/50

  by heat-treatment · CPC title

• C25D5/18

  Electroplating using modulated, pulsed or reversing current · CPC title

• C25D3/20 Primary

  of iron · CPC title