Patent US3687740A successfully refreshed from Google Patents.
US3687740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat resistant chromate conversion coatings
Assignee: United States Department of the Army
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Filing: 1971-01-22
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Granted: 1972-08-29
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Expires: 1991-01-22
Abstract
Abstract METHODS ARE DESCRIBED FOR PREVENTING ADVERSE EFFECT OF HEAT ON THE SALT SPRAY CORROSION RESISTANCE OF CHEMICAL CHROMATE CONVERSION COATED ZINC OR ALUMINUM SPECIMENS BY SIMPLY IMMERSING THE SPECIMENS FOR A PERIOD A ABOUT 1 TO 3 MINUTES IN A SOLUTION OF SODIUM SILICATE, BARIUM NITRATE, OR GLYCERINE. THE SILICATES AND NITRATES ARE RINSED OFF AFTER THE IMMERSION STEP AND THEN DRAIN DRIED WHEREAS THE SPECIMENS IMMERSED IN THE GLYCERINE SOLUTION ARE MERELY DRAIN DRIED AFTER THE IMMERSION STEP.
Inventors
- 👤 Fred Pearlstein
- 👤 Margaret R D Ambrosio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:48
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/82; C23C22/83
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |