US3857766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for anodizing aluminum and its alloys
Assignee: Permaloy Corp
•
Filing: 1972-08-03
•
Granted: 1974-12-31
•
Expires: 1992-08-03
Abstract
Abstract A method of anodizing aluminum and its alloys utilizing a suitable anodizing electrolyte and a pulsed direct current. The direct current used provides a substantially constant anodizing current interspersed with at least six pulses per second of higher, smoothly peaked, direct current. It has been found that the greater the number of pulses per second, the more superior the anodic coating obtained. The electrolyte used can be sulfuric acid (125 to 300 grams of sulfuric acid per liter of water) preferably containing a 0.1 to 0.2 grams per liter of sodium lignosulfonate or other such sulfonated organic compound as a stabilizer. A mixture of sulfosalicylic acid and sulfuric acid or a mixture of sulfuric and oxalic acid can be used.
Inventors
- 👤 J Woods
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:12
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/024; C25D11/06; C25D11/08; Y; Y10; Y10S; Y10S204/00; Y10S204/08; Y10S204/09
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
118 words
A PROCESS FOR ANODIZING AN OBJECT OF ALUMINUM OR ALUMIMUN ALLOY COMPRISING PLACING SAID OBJECT AS AN ANODE IN AN ANODIZING ELECTROLYTE CONTAINED WITHIN AN ELECTROLYTIC CELL HOUSING, SAID HOUSING BEING A CATHODE AND BEING CONTINUALLY CONNECTED TO A NEGATIVE CURRENT POTENTIAL; AND SUBJECTING THE ANODE TO A CONTINUALLY APPLIED POSITION DIRECT CURRENT HAVING AN AVERAGE DIRECT POSITIVE CURRENT VOLTAGE INTERSPERSED WITH APPLIED PEAKED PULSE OF HIGHER LEVEL POSITIVE CURRENT VOLTAGE, SAID PEAKED PULSES HAVING A WAVE PATTERN SUCH THAT THE TIME FROM AVERAGE CURRENT TO PEAKED PULSE CURRENT IS GREATER THAN THE TIME FROM PEAKED PULSE CURRENT BACK TO AVERAGE CURRENT, FOR A PERIOD OF TIME SUFFICIENT TO ANODIZE THE OBJECT WITH A COATING OF DESIRED THICKNESS.
Claim 2
Dependent Claim
118 words
A PROCESS FOR ANODIZING AN OBJECT OF ALUMINUM OR ALUMIMUN ALLOY COMPRISING PLACING SAID OBJECT AS AN ANODE IN AN ANODIZING ELECTROLYTE CONTAINED WITHIN AN ELECTROLYTIC CELL HOUSING, SAID HOUSING BEING A CATHODE AND BEING CONTINUALLY CONNECTED TO A NEGATIVE CURRENT POTENTIAL; AND SUBJECTING THE ANODE TO A CONTINUALLY APPLIED POSITION DIRECT CURRENT HAVING AN AVERAGE DIRECT POSITIVE CURRENT VOLTAGE INTERSPERSED WITH APPLIED PEAKED PULSE OF HIGHER LEVEL POSITIVE CURRENT VOLTAGE, SAID PEAKED PULSES HAVING A WAVE PATTERN SUCH THAT THE TIME FROM AVERAGE CURRENT TO PEAKED PULSE CURRENT IS GREATER THAN THE TIME FROM PEAKED PULSE CURRENT BACK TO AVERAGE CURRENT, FOR A PERIOD OF TIME SUFFICIENT TO ANODIZE THE OBJECT WITH A COATING OF DESIRED THICKNESS.
Claim 3
Dependent Claim
18 words
A process as in claim 1, wherein the direct current is applied through a pulsed constant current charger.
Claim 4
Dependent Claim
15 words
A process as in claim 1, wherein at least six peaked pulses occur per second.
Claim 5
Dependent Claim
24 words
A process as in claim 3, wherein the pulses peak at a voltage which is at least about twice the average direct current voltage.
Claim 6
Dependent Claim
43 words
A process as in claim 3, wherein the electrolyte comprises an aqueous solution of sulfuric acid containing between one hundred twenty-five and three hundred grams of sulfuric acid per liter of water and one-tenth to two tenths grams of sodium lignosulfonate per liter.
References Cited (Backward Citations)
CA548071A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |