US3874901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coating system for superalloys
Assignee: General Electric Co
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Filing: 1973-04-23
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Granted: 1975-04-01
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Expires: 1993-04-23
Abstract
Abstract A protective coating system is provided for nickel-base and cobalt-base superalloys which is capable of imparting oxidation and corrosion resistance at elevated temperatures. The superalloy body is first coated by physical vapor deposition with a composition consisting essentially of chromium, aluminum and, optionally, a member selected from the group consisting of yttrium and the rare earth elements and at least one element selected from the group consisting of iron, cobalt and nickel. Thereafter the body is coated with an overlayer of aluminum by physical vapor deposition and heat treated to cause the interdiffusion of aluminum into the first coating layer and thereby greatly enhance the hot corrosion and oxidation resistance of the coating system.
Inventors
- 👤 Iii John R Rairden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:43
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/58; C23C14/5806; C23C14/06; C23C14/14; C23C14/16; C23C14/5893; C23C26/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
112 words
A METHOD OF IMPROVING THE HIGH TEMPERATURE OXIDATION AND CORROSION RESISTANCE OF A NICKEL-BASE OR A COBALT-BASE SUPERALLOY BODY COMPRISING THE STEPS OF: A. COATING THE SUPERALLOY BODY BY PHYSICAL VAPOR DEPOSITION WITH A COMPOSITION CONSISTING ESSENTIALLY OF CHROMIUM, ALUMINUM, A MEMBER SELECTED FROM THE GROUP CONSISTING OF YTTRIUM AND THE RARE EARTH ELEMENTS, AND AT LEAST ONE ELEMENT SELECTED FROM THE GROUP CONSISTING OF IRONM COBALT AND NICKEL, AND B. SUBJECTING THE COATED BODY TO AN OVERCOAT OF ALUMINUM DEPOSITED BY PHYSICAL VAPOR DEPOSITION, AND C. HEAT TREATING THE DUPLEX COATING TO CAUSE THE INTERDIFFUSION OF ALUMINUM WITH THE FIRST COATING TO INCREASE THE OXIDATION AND CORROSION RESISTANCE OF THE COATING.
Claim 2
Independent Claim
112 words
A METHOD OF IMPROVING THE HIGH TEMPERATURE OXIDATION AND CORROSION RESISTANCE OF A NICKEL-BASE OR A COBALT-BASE SUPERALLOY BODY COMPRISING THE STEPS OF: A. COATING THE SUPERALLOY BODY BY PHYSICAL VAPOR DEPOSITION WITH A COMPOSITION CONSISTING ESSENTIALLY OF CHROMIUM, ALUMINUM, A MEMBER SELECTED FROM THE GROUP CONSISTING OF YTTRIUM AND THE RARE EARTH ELEMENTS, AND AT LEAST ONE ELEMENT SELECTED FROM THE GROUP CONSISTING OF IRONM COBALT AND NICKEL, AND B. SUBJECTING THE COATED BODY TO AN OVERCOAT OF ALUMINUM DEPOSITED BY PHYSICAL VAPOR DEPOSITION, AND C. HEAT TREATING THE DUPLEX COATING TO CAUSE THE INTERDIFFUSION OF ALUMINUM WITH THE FIRST COATING TO INCREASE THE OXIDATION AND CORROSION RESISTANCE OF THE COATING.
Claim 3
Dependent Claim
41 words
The method of claim 1, wherein said composition consists essentially in weight percent of 14-35 percent chromium, 4-20 percent aluminum, 0-3 percent yttrium and the balance being a member selected from the group consisting of iron, cobalt, nickel, and mixtures thereof.
Claim 4
Dependent Claim
28 words
The method of claim 1, wherein said composition consists essentially in weight percent of 25-29 percent chromium, 12-14 percent aluminum, 0-0.9 percent yttrium and the balance being iron.
Claim 5
Dependent Claim
28 words
The method of claim 1, wherein said composition consists essentially in weight percent of 19-24 percent chromium, 13-17 percent aluminum, 0-0.9 percent yttrium, and the balance being cobalt.
Claim 6
Dependent Claim
28 words
The method of claim 1, wherein said composition consists essentially in weight percent of 20-35 percent chromium, 15-20 percent aluminum, 0-0.30 percent yttrium and the balance being nickel.
Claim 7
Dependent Claim
30 words
The method of claim 1, wherein said heat treating is at a temperature in the range of about 950* C. up to the solutionizing heat treatment of the superalloy body.
Claim 8
Dependent Claim
12 words
The method of claim 6, wherein said body is a nickel-base superalloy.
Claim 9
Dependent Claim
12 words
The method of claim 6, wherein said body is a cobalt-base superalloy.
Claim 10
Dependent Claim
34 words
The method of claim 6, wherein the first coating has a thickness of about 1-7 mils and the heat treated aluminum overcoating penetrates into the first coating to a depth of about 1-2 mils.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |