US4072588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the anodic polishing of surfaces of intermetallic niobium compounds and niobium alloys
Assignee: Siemens AG
•
Filing: 1977-02-15
•
Granted: 1978-02-07
•
Expires: 1997-02-15
Abstract
Abstract The surface of an intermetallic niobium compound or niobium alloy to be polished is electrically shunted across a niobium part and immersed in electrolyte together with the latter permitting relatively thick surface layers of niobium compounds of high quality which are used for superconducting a-c apparatus to be produced.
Inventors
- 👤 Heinrich Diepers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:16
CPC Classifications
C; C25; C25F; C25F3/00; C25F3/16; C25F3/22; C25F3/26; H; H10; H10N; H10N60/00; H10N60/01; Y; Y10; Y10S; Y10S204/00; Y10S204/07
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
176 words
A method for the anodic polishing of surfaces of intermetallic niobium compounds and niobium alloys comprising: a. placing a niobium part as an anode and a cathode, in an electrolyte consisting of 86 to 93% by weight H 2 SO 4 , 1.5 to 4% by weight HF and 5.5 to 10.0% by weight H 2 O with a temperature of between 15° and 50° C; b. electrically shunting the surface to be polished across the niobium part; c. adjusting a constant voltage of between 9 and 15 V between the niobium part and the cathode in such a manner that damped current oscillations are superimposed on the electrolyte current; d. switching off the voltage at the latest after the current oscillations have decayed completely, and keeping it off until the oxide layer built up during the current oscillations is dissolved; e. subsequently again adjusting a constant voltage between 9 and 15 V so that damped current oscillations occur; and, f. repeating the sequence of states with the voltage switched on and off several more times.
Claim 2
Independent Claim
176 words
A method for the anodic polishing of surfaces of intermetallic niobium compounds and niobium alloys comprising: a. placing a niobium part as an anode and a cathode, in an electrolyte consisting of 86 to 93% by weight H 2 SO 4 , 1.5 to 4% by weight HF and 5.5 to 10.0% by weight H 2 O with a temperature of between 15° and 50° C; b. electrically shunting the surface to be polished across the niobium part; c. adjusting a constant voltage of between 9 and 15 V between the niobium part and the cathode in such a manner that damped current oscillations are superimposed on the electrolyte current; d. switching off the voltage at the latest after the current oscillations have decayed completely, and keeping it off until the oxide layer built up during the current oscillations is dissolved; e. subsequently again adjusting a constant voltage between 9 and 15 V so that damped current oscillations occur; and, f. repeating the sequence of states with the voltage switched on and off several more times.
Claim 3
Dependent Claim
33 words
The method according to claim 1, wherein said niobium part has a surface area facing the cathode which is at least as large as the surface area of the surface to be polished.
Claim 4
Dependent Claim
18 words
The method according to claim 2 wherein said surface to be polished is an Nb 3 Sn surface.
Claim 5
Dependent Claim
18 words
The method according to claim 1 wherein said surface to be polished is an Nb 3 Sn surface.
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) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |