US3939293A
Expired / Lapsed
US
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Method for passivating chromium
Assignee: International Business Machines Corp
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Filing: 1974-04-30
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Granted: 1976-02-17
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Expires: 1994-04-30
Abstract
Abstract Chromium is passivated by forming a chromium oxide layer thereon by heating at temperatures of about 450°C in an atmosphere containing oxygen. While useful, per se, the process finds particular application as an integral part of overall processing schemes where thermal cycles are used.
Inventors
- 👤 Vlasta Brusic
- 👤 Robert O. Lussow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:51
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/08; C23C8/10; C23C8/12; H; H01; H01J; H01J9/00; H01J9/24; H01J9/26; H01J9/261
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
39 words
A process for passivating chromium which comprises contacting chromium at a temperature of from about 425°C to about 475°C with O 2 for a period of time greater than twenty minutes to grow a passivating chromium oxide film thereon.
Claim 2
Dependent Claim
39 words
A process for passivating chromium which comprises contacting chromium at a temperature of from about 425°C to about 475°C with O 2 for a period of time greater than twenty minutes to grow a passivating chromium oxide film thereon.
Claim 3
Dependent Claim
11 words
The process of claim 1 where the temperature is about 450°C.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein the chromium is in the form of a thin film.
Claim 5
Dependent Claim
20 words
The process of claim 3 wherein the chromium has a thickness of from about 800 angstroms to about 2,500 angstroms.
Claim 6
Dependent Claim
24 words
The process of claim 1 wherein the process is conducted at an oxygen partial pressure of from about 0.01 atmosphere to about 10 atmospheres.
Claim 7
Dependent Claim
20 words
The process of claim 1 wherein said contacting is conducted while said chromium is coated with a particulate glassy frit.
Claim 8
Dependent Claim
18 words
The process of claim 1 wherein moist air is slowly flowed over the chromium to provide said oxygen.
Claim 9
Dependent Claim
33 words
The process of claim 1 wherein said chromium is overcoated on a thin layer of copper which is in turn overcoated on a second thin layer of chromium adhering to a glass substrate.
Claim 10
Dependent Claim
21 words
The process of claim 8 wherein said second thin layer of chromium adhering to said glass substrate covers said glass substrate.
Claim 11
Dependent Claim
38 words
The process of claim 1 wherein the process is conducted at a oxygen partial pressure of from about 0.01 atmosphere to about 10 atmospheres and wherein moist air is slowly flowed over the chromium to provide said oxygen.
Claim 12
Dependent Claim
27 words
The process of claim 1 wherein said contacting is carried out for a minimum of about 1 hour to a maximum of about two and one-half hours.
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) | 1979-02-16 | 1979-08-18 | 1980-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-16 | 1983-08-18 | 1984-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-16 | 1987-08-18 | 1988-02-17 | $7700.00 | Window Closed / Lapsed |