US4156042A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coating articles having fine bores or narrow cavities in a pack-cementation process
Assignee: UK Secretary of State for Defence
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Filing: 1978-02-22
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Granted: 1979-05-22
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Expires: 1998-02-22
Abstract
Abstract A process for coating an article such as a turbine blade composed of nickel-base alloy, comprises the steps of surrounding the article by a particulate pack in a chamber, the pack including coating material in elemental or chemically combined form, said coating material selected from the group comprising aluminium, chromium, titanium, zirconium tantalum, niobium, yttrium, rare earth metals, boron and silicon together with a halide activator, preferably of low volatility, and cyclically varying the pressure of an inert gas or a reducing gas or a mixture of said gases contained within said chamber, while maintaining the contents of the chamber at a temperature sufficient to transfer coating material onto the surface of the article and form a diffusion coating thereon.
Inventors
- 👤 Cecil Hayman
- 👤 James E. Restall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:08
CPC Classifications
C; C23; C23C; C23C10/00; C23C10/28; C23C10/34
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
133 words
A process for coating an article having fine bores or narrow cavities with a diffusion coating comprising the following steps: a. enclosing the article in a chamber together with a particulate pack including a coating material in elemental or chemically combined form, said coating material selected from the group consisting of aluminium, chromium, titanium, zirconium, tantalum, niobium, yttrium, rate earth metals, boron and silicon, together with a halide activator of low volatility, b. introducing an inert gas into the chamber, and c. cyclically varying the pressure of said gas within the range 0-100 torr at a rate of not less than 2 cycles per minute whilst maintaining said pack and article at a temperature sufficient to transfer said coating material on to the surface of said article to form a diffusion coating therewith.
Claim 2
Dependent Claim
133 words
A process for coating an article having fine bores or narrow cavities with a diffusion coating comprising the following steps: a. enclosing the article in a chamber together with a particulate pack including a coating material in elemental or chemically combined form, said coating material selected from the group consisting of aluminium, chromium, titanium, zirconium, tantalum, niobium, yttrium, rate earth metals, boron and silicon, together with a halide activator of low volatility, b. introducing an inert gas into the chamber, and c. cyclically varying the pressure of said gas within the range 0-100 torr at a rate of not less than 2 cycles per minute whilst maintaining said pack and article at a temperature sufficient to transfer said coating material on to the surface of said article to form a diffusion coating therewith.
Claim 3
Dependent Claim
25 words
A process as in claim 1 wherein the vapour, sublimation or dissociation pressure of the halide activator does not exceed atmospheric pressure at said temperature.
Claim 4
Dependent Claim
28 words
A process as in claim 1 wherein the vapour, sublimation or dissociation pressure of the halide activator does not exceed 15 torr at a temperature of 900° C.
Claim 5
Dependent Claim
18 words
A process as in claim 1 wherein the maximum pressure of the gas does not exceed 100 torr.
Claim 6
Dependent Claim
25 words
A process as in claim 1 wherein the maximum pressure of the gas is about 50 torr and the minimum pressure is about 10 torr.
Claim 7
Dependent Claim
19 words
A process as in claim 1 wherein said coating material comprises aluminium and the halide activator comprises aluminium fluoride.
Claim 8
Dependent Claim
19 words
A process as in claim 1 wherein said coating material comprises aluminium and said halide activator comprises sodium chloride.
Claim 9
Dependent Claim
19 words
A process as in claim 1 wherein said coating material comprises aluminium and said halide activator comprises sodium fluoride.
Claim 10
Dependent Claim
17 words
A process as in claim 1 wherein the pack includes a filler for supporting the coating material.
Claim 11
Dependent Claim
12 words
A process in claim 9 wherein the filler comprises a refractory oxide.
Claim 12
Dependent Claim
13 words
A process as in claim 10 wherein the refractory oxide is aluminium oxide.
Claim 13
Dependent Claim
44 words
A process as in claim 1 wherein the article is held out of contact with said particulate pack in a cage permitting vapour to pass from the particulate pack to the inside of the cage but retarding flow to the outside of the cage.
Claim 14
Dependent Claim
150 words
A process for coating a metallic article having fine bores or narrow cavities with a diffusion coating comprising the following steps: a. surrounding the article by a particulate pack in a chamber, the pack including coating material in elemental or chemically combined form, said coating material selected from the group consisting of aluminium, chromium, titanium, zirconium, tantalum, nobium, yttrium, rate earth metals, boron and silicon, b. introducing an inert gas or a reducing gas or a mixture of said gases into the chamber, c. introducing a vapour comprising a halide activator of low volatility into the chamber, and d. cyclically varying the pressure of said gas or gases within the range of 0-100 torr at a rate of not less than 2 cycles per minute whilst maintaining said pack and article at a temperature sufficient to transfer said coating material on to said article and form a diffusion coating thereon.
Claim 15
Dependent Claim
150 words
A process for coating a metallic article having fine bores or narrow cavities with a diffusion coating comprising the following steps: a. surrounding the article by a particulate pack in a chamber, the pack including coating material in elemental or chemically combined form, said coating material selected from the group consisting of aluminium, chromium, titanium, zirconium, tantalum, nobium, yttrium, rate earth metals, boron and silicon, b. introducing an inert gas or a reducing gas or a mixture of said gases into the chamber, c. introducing a vapour comprising a halide activator of low volatility into the chamber, and d. cyclically varying the pressure of said gas or gases within the range of 0-100 torr at a rate of not less than 2 cycles per minute whilst maintaining said pack and article at a temperature sufficient to transfer said coating material on to said article and form a diffusion coating thereon.
Claim 16
Dependent Claim
12 words
A process as in claim 13 wherein the reducing gas comprises hydrogen.
References Cited (Backward Citations)
US2210832A
Cited
DE1147101B
Cited
US3079276A
Cited
US3158499A
Cited
US3257230A
Cited
GB1070396A
Cited
US3343982A
Cited
US3373018A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-05-21 | 1982-11-20 | 1983-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-21 | 1986-11-20 | 1987-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-21 | 1990-11-20 | 1991-05-22 | $7700.00 | Window Closed / Lapsed |