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US4759993A
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Plasma chemical vapor deposition SiO2-x coated articles and plasma assisted chemical vapor deposition method of applying the coating
Assignee: Ovonic Synthetic Materials Co Inc
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Filing: 1985-04-25
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Granted: 1988-07-26
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Expires: 2005-04-25
Abstract
Abstract A coated stainless steel article and a method of preparing the article are disclosed. The coating is a plasma chemical vapor deposited coating, formed from a plasma of nitrous oxide, a silane, and an energy transfer agent (such as He, Ar). The resulting coating is adherent, corrosion resistant, and has a thickness sufficient to mask and cover the features of the stainless steel substrate, and to provide a pitting potential (in 3.5% NaCl) of greater than 600 millivolts, a J.I.S. 8502 (1982) versus a saturated calomel electrode a salt spray test rating in 5% NaCl-0.02% hydrogen peroxide of at least B.
Inventors
- 👤 Purnachandra Pai
- 👤 Benjamin Chao
- 👤 Keith Hart
- 👤 Yasuo Takagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:31
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/22; C23C14/24; C23C16/00; C23C16/22; C23C16/30; C23C16/40; C23C16/401; C23C16/402
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
123 words
A stainless steel article having an adherent, corrosion resistant coating thereon, substantially free of nitrogen and hydrogen, and comprising microwave plasma assisted chemical vapor deposition deposited SiO 2-x where x is from 0.0 to 0.4, said coating being deposited from a deposition gas at a pressure of 10 -3 to 10 -1 torr and consisting essentially of 10 to 40 volume percent silanes, 20 to 80 volume percent nitrous oxide, balance inert gas energy transfer agent, said inert gas energy transfer agent being at least 35 volume percent of the deposition gas where the ratio of nitrous oxide to silanes is 3:1 to 5:1, and the ratio of (nitrous oxide plus silanes) to inert gas energy transfer agent is from 0.4:1 to 2.5:1.
Claim 2
Dependent Claim
123 words
A stainless steel article having an adherent, corrosion resistant coating thereon, substantially free of nitrogen and hydrogen, and comprising microwave plasma assisted chemical vapor deposition deposited SiO 2-x where x is from 0.0 to 0.4, said coating being deposited from a deposition gas at a pressure of 10 -3 to 10 -1 torr and consisting essentially of 10 to 40 volume percent silanes, 20 to 80 volume percent nitrous oxide, balance inert gas energy transfer agent, said inert gas energy transfer agent being at least 35 volume percent of the deposition gas where the ratio of nitrous oxide to silanes is 3:1 to 5:1, and the ratio of (nitrous oxide plus silanes) to inert gas energy transfer agent is from 0.4:1 to 2.5:1.
Claim 3
Dependent Claim
33 words
The stainless steel article of claim 1 wherein the article has a stainless steel substrate having surface features of up to 2000 Angstroms, and the coating is thick enough to cover the features.
Claim 4
Dependent Claim
36 words
The stainless steel article of claim 2 wherein the stainless steel is bright annealed, the surface features have a characteristic dimension of about 500 to 1000 angstroms, and the coating is at least 0.1 micron thick.
Claim 5
Dependent Claim
36 words
The stainless steel article of claim 2 wherein the stainless steel is pickled, the surface features have a characteristic dimension of at least about 2000 angstroms, and the coating is at least about 0.1 micron thick.
Claim 6
Dependent Claim
25 words
The article of claim 1 wherein the inert gas energy transfer agent is an inert gas chosen from the group consisting of He and Ar.
Claim 7
Dependent Claim
14 words
The article of claim 5 wherein the inert gas energy transfer agent is He.
Claim 8
Dependent Claim
20 words
The article of claim 1 wherein the silane is chosen from the group consisting of silane, disilane, and higher silanes.
Claim 9
Dependent Claim
14 words
The article of claim 7 wherein the silane consists essentially of SiH 4 .
Claim 10
Dependent Claim
21 words
The article of claim 1 wherein said coating is deposited at a deposition rate of at least 500 angstroms per second.
Claim 11
Dependent Claim
31 words
The article of claim 1 wherein the substrate in stainless steel, and the coating has a pitting potential of at least 600 mv vs SCE in 3.5 weight percent NaCl solution.
Claim 12
Dependent Claim
32 words
The article of claim 1 wherein the substrate is stainless steel and the article has a J.I.S. H-8502 (1982) five minute pinhole rating in potassium ferricyinide-potassium ferrocyanide-sodium chloride of at least 9.8-2.
Claim 13
Dependent Claim
34 words
The article of claim 1 wherein the substrate is stainless steel and the article has a J.I.S. H-8502 (1982) twenty four hour salt spray rating in 5% NaCl-0.2% hydrogen peroxide of at least B.
Claim 14
Independent Claim
172 words
A method of depositing a corrosion resistant, adherent coating on a stainless steel substrate comprising the steps of: (a) degreasing the stainless steel substrate; (b) heating the stainless steel substrate to a temperature range to facilitate adhesion of the coating thereon; (c) forming a deposition gas of nitrous oxide, a silane, and an energy transfer agent at a pressure of 10 -3 to 10 -1 torr, said deposition gas consisting essentially of (i) 10 to 40 volume percent silanes, (ii) 20 to 80 volume percent notrous oxide, and (iii) balance inert gas energy transfer agent, said inert gas energy transfer agent being at least 35 volume percent of the deposition gas; where the ratio of nitrous oxide to silanes is 3:1 to 5:1, and the ratio of (nitrous oxide plus silanes) to insert gas energy transfer agent is 0.4:1 to 2.5:1; (d) forming a plasma of the deposition gas; and (e) contacting the stainless steel substrate with deposition gas under plasma assisted chemical vapor deposition conditions whereby to form the coating thereon.
Claim 15
Independent Claim
172 words
A method of depositing a corrosion resistant, adherent coating on a stainless steel substrate comprising the steps of: (a) degreasing the stainless steel substrate; (b) heating the stainless steel substrate to a temperature range to facilitate adhesion of the coating thereon; (c) forming a deposition gas of nitrous oxide, a silane, and an energy transfer agent at a pressure of 10 -3 to 10 -1 torr, said deposition gas consisting essentially of (i) 10 to 40 volume percent silanes, (ii) 20 to 80 volume percent notrous oxide, and (iii) balance inert gas energy transfer agent, said inert gas energy transfer agent being at least 35 volume percent of the deposition gas; where the ratio of nitrous oxide to silanes is 3:1 to 5:1, and the ratio of (nitrous oxide plus silanes) to insert gas energy transfer agent is 0.4:1 to 2.5:1; (d) forming a plasma of the deposition gas; and (e) contacting the stainless steel substrate with deposition gas under plasma assisted chemical vapor deposition conditions whereby to form the coating thereon.
Claim 16
Dependent Claim
23 words
The method of claim 13 wherein the energy transfer agent is an inert gas chosen from the group consisting of He and Ar.
Claim 17
Dependent Claim
12 words
The method of claim 14 wherein the energy transfer agent is He.
Claim 18
Dependent Claim
20 words
The method of claim 13 wherein the silane is chosen from the group consisting of silane, disilane, and higher silanes.
Claim 19
Dependent Claim
14 words
The method of claim 16 wherein the silane consists essentially of SiH 4 .
Claim 20
Dependent Claim
21 words
The method of claim 13 wherein said coating is deposited at a deposition rate of at least 500 angstroms per second.
Claim 21
Dependent Claim
24 words
The method of claim 13 wherein the stainless steel substrate has surface features and the coating is thick enough to cover the surface features.
Claim 22
Dependent Claim
34 words
The method of claim 19 wherein the stainless steel is bright annealed, the surface features have a characteristic dimension of about 500 to 1000 angstroms, and the coating is at least 0.1 micron thick.
Claim 23
Dependent Claim
34 words
The method of claim 19 wherein the stainless steel is pickled, the surface features have a characteristic dimension of at least about 2000 angstroms, and the coating is at least about 0.1 micron thick.
Claim 24
Dependent Claim
26 words
The method of claim 19 wherein the resulting coating has a pitting potential of at least 600 mV vs. S.C.E. in 3.5 weight percent NaCl solution.
Claim 25
Dependent Claim
29 words
The method of claim 19 wherein the resulting coating has a J.I.S. H-8502 (1982) five minute pinhold rating in potassium ferricyanide - potassium ferrocyanide-sodium chloride of at least 9.8-2.
Claim 26
Dependent Claim
30 words
The method of claim 19 wherein the resulting coating has a J.I.S. H-8502 (1982) twenty four salt spray rating in 5% NaCl - 0.2% hydrogen peroxide of at least B.
Claim 27
Dependent Claim
10 words
The method of claim 23 comprising continuously depositing said coating.
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) | 1991-07-26 | 1992-01-25 | 1992-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-26 | 1996-01-25 | 1996-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-26 | 2000-01-25 | 2000-07-26 | $7700.00 | Window Closed / Lapsed |