US4846940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrolytically deposited hard chronium coatings
Assignee: Federal Mogul Burscheid GmbH
•
Filing: 1988-01-22
•
Granted: 1989-07-11
•
Expires: 2008-01-22
Abstract
Abstract Solid particles of primarily hard substances, solid lubricants, ductile metals or their alloys and/or molten polymers are embedded in a network of cracks of hard chromium coatings to attain improved physical characteristics, primarily to increase wear resistance, sliding behavior, ductility and corrosion resistance. The chrome plating process takes place in a microcrack-forming chrome-plating electrolyte with solid particles dispersed therein and with one-time or repeated current reversal so that, if the workpiece is connected to the anode, the network of microcracks in the chromium coating is widened and solid particles are embedded within the cracks. Preferred uses are as coatings on the bearing surfaces of piston rings or cylinder bearing sleeves for internal-combustion engines.
Inventors
- 👤 Hans-Jochem Neuhauser
- 👤 Ulrich Buran
- 👤 Rudolf Linde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:34
CPC Classifications
C; C25; C25D; C25D15/00; C25D15/02
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
26 words
An electrolytically-deposited hard chromium coating comprising multiple chromium layers, each layer having a network of cracks within at least one of which solid particles are embedded.
Claim 2
Dependent Claim
26 words
An electrolytically-deposited hard chromium coating comprising multiple chromium layers, each layer having a network of cracks within at least one of which solid particles are embedded.
Claim 3
Dependent Claim
23 words
The hard chromium coating of claim 1, wherein the thickness of the hard chromium coating is between about 0.01 μm and 1.0 mm.
Claim 4
Dependent Claim
19 words
The hard chromium coating of claim 1, wherein the width of the cracks is greater than about 0.001 mm.
Claim 5
Dependent Claim
23 words
The hard chromium coating of claim 1, wherein the grain size of the embedded solid particles is about 0.0005 mm and 0.015 mm.
Claim 6
Dependent Claim
19 words
The hard chromium coating of claim 1, wherein the solid particles embedded in the cracks comprise a hard material.
Claim 7
Dependent Claim
32 words
The hard chromium coating of claim 5, wherein the hard material is selected from the group consisting of tungsten carbide, chromium carbide, aluminum oxide, silicon carbide, silicon nitride, boron carbide and diamond.
Claim 8
Dependent Claim
15 words
The hard chromium coating of claim 1, wherein the solid particles comprise a solid lubricant.
Claim 9
Dependent Claim
23 words
The hard chromium coating of claim 7, wherein the solid lubricant is selected from the group consisting of graphite, hexagonal boronitride and polytetrafluoroethylene.
Claim 10
Dependent Claim
27 words
The hard chromium coating of claim 1, wherein the solid particles embedded in the cracks are selected from the group consisting of ductile metals and metal alloys.
Claim 11
Dependent Claim
28 words
The hard chromium coating of claim 9, wherein the ductile metals and/or the metal alloys are selected from the group consisting of titanium, tin, iron oxide and bronze.
Claim 12
Dependent Claim
19 words
The hard chromium coating of claim 1, wherein the solid particles embedded in the cracks comprise melted thermoplastic polymers.
Claim 13
Dependent Claim
26 words
The hard chromium coating of claim 1, wherein the solid particles embedded in the cracks are selected from the group consisting of organic and inorganic dyestuffs.
Claim 14
Dependent Claim
42 words
The hard chromium coating of claim 1, wherein the said particles embedded in the cracks are mixtures of at least two components of the group consisting of hard substance particles, solids particles, metals, metal alloys, organic thermoplastics and organic and inorganic dyestuffs.
Claim 15
Dependent Claim
33 words
The hard chromium coating of claim 1, wherein the chromium coating comprises a plurality of chromium layers comprising different solid particles or solid particle mixtures enbedded within in the cracks of said layers.
Claim 16
Dependent Claim
24 words
The hard chromium coating of claim 14, wherein the cracks of each individual chromium layer are filled to a different degree with solids particles.
Claim 17
Dependent Claim
21 words
The hard chromium coating of claim 1, wherein at least one layer of said multiple chromium layers contains a hard material.
Claim 18
Dependent Claim
22 words
The hard chromium coating of claim 16, wherein at least one other layer of said multiple chromium layers contains a solid lubricant.
Claim 19
Dependent Claim
23 words
The hard chromium coating of claim 16, wherein at least one other layer of said multiple chromium layers is free of solid particles.
Claim 20
Independent Claim
139 words
A method for electrolytically depositing a hard chromium coating on a substrate comprising chrome-plating the substrate connected as a first electrode in the presence of a microcrack-forming chrome-plating electrolyte contacting a second electrode and containing suspended solid particles, said plating being conducted at least once with the aid of stirring and/or blowing in air for a time effective to deposit a hard chromium coating having a network of cracks which extends throughout the entire thickness of the coating, and having solid particles embedded within the cracks; and said plating being carried out during a plurality of plating periods including at least one period during which the substrate is connected as a cathode and the electrolyte contacts an anode and at least one plating period during which the substrate is connected as an anode and the electrolyte contacts a cathode.
Claim 21
Independent Claim
139 words
A method for electrolytically depositing a hard chromium coating on a substrate comprising chrome-plating the substrate connected as a first electrode in the presence of a microcrack-forming chrome-plating electrolyte contacting a second electrode and containing suspended solid particles, said plating being conducted at least once with the aid of stirring and/or blowing in air for a time effective to deposit a hard chromium coating having a network of cracks which extends throughout the entire thickness of the coating, and having solid particles embedded within the cracks; and said plating being carried out during a plurality of plating periods including at least one period during which the substrate is connected as a cathode and the electrolyte contacts an anode and at least one plating period during which the substrate is connected as an anode and the electrolyte contacts a cathode.
Claim 22
Dependent Claim
34 words
The method of claim 19, wherein the time during which the workpiece is connected as a cathode is longer by a multiple than the time during which the workpiece is connected as an anode.
Claim 23
Dependent Claim
21 words
The process of claim 19, wherein the thickness of the hard chromium coating is between about 0.01 μm and 1.0 mm.
Claim 24
Dependent Claim
17 words
The process of claim 19, wherein the width of the cracks is greater than about 0.001 mm.
Claim 25
Dependent Claim
21 words
The process of claim 19, wherein the grain size of the embedded solid particles is about 0.0005 mm and 0.015 mm.
Claim 26
Dependent Claim
45 words
The process of claim 19, wherein the solid particles are selected from the group consisting of tungsten carbide, chromium carbide, aluminum oxide, silicon carbide, silicon nitride, boron carbide, diamond, graphite, hexagonal boronitride, polytetrafluoroethylene, titanium, tin, iron oxide, bronze, thermoplastic polymers, and organic and inorganic dyestuffs.
Claim 27
Independent Claim
106 words
A method for electrolytically depositing a hard chromium coating on a substrate, comprising: chrome-plating the substrate connected as a first electrode in the presence of a microcrack-forming chrome-plating electrolyte contacting a second electrode and containing suspended solid particles, said plating being conducted at least once with the aid of stirring and/or blowing in air for a time effective to deposit a hard chromium coating having a network of cracks which extends throughout the entire thickness of the coating, and having solid particles embedded within the cracks; and further chrome-plating the substrate in the presence of a microcrackforming chrome-plating electrolyte in the substantial absence of solid particles.
Claim 28
Independent Claim
106 words
A method for electrolytically depositing a hard chromium coating on a substrate, comprising: chrome-plating the substrate connected as a first electrode in the presence of a microcrack-forming chrome-plating electrolyte contacting a second electrode and containing suspended solid particles, said plating being conducted at least once with the aid of stirring and/or blowing in air for a time effective to deposit a hard chromium coating having a network of cracks which extends throughout the entire thickness of the coating, and having solid particles embedded within the cracks; and further chrome-plating the substrate in the presence of a microcrackforming chrome-plating electrolyte in the substantial absence of solid particles.
References Cited (Backward Citations)
GB1098066A
Cited
US3356467A
Cited
GB1070343A
Cited
GB1220331A
Cited
DE2146908A1
Cited
DE2230676A1
Cited
US3844910A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |