US3615345A
Expired / Lapsed
US
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Method for producing ultra-high purity metal
Assignee: Philips North America LLC
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Filing: 1968-08-28
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Granted: 1971-10-26
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Expires: 1988-08-28
Abstract
Abstract For electron-beam zone-refining of metal, at least one zonerefining pass is conducted in a hydrogen atmosphere at a system pressure sufficiently low to prevent formation of a hydrogen arcdischarge. This is followed by at least one zone refining pass in a high vacuum. The resulting metal is extremely pure.
Inventors
- 👤 George W King
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:34
CPC Classifications
C; C30; C30B; C30B13/00; C30B13/16; C30B13/22
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
26 words
The method as specified in claim 1, wherein said hydrogen atmosphere is at a system pressure of no greater than about 5 X 10 3 torr.
Claim 2
Dependent Claim
31 words
The method as specified in claim 1, wherein said hydrogen atmosphere is at a system pressure of from about 1 X 10 4 torr to about 3 X 10 4 torr.
Claim 3
Dependent Claim
30 words
The method as specified in claim 1, wherein prior to said zone-refining pass in said hydrogen atmosphere, at least one of said zone-refining passes is conducted in a high vacuum.
Claim 4
Dependent Claim
21 words
The method as specified in claim 1, wherein there are conducted at least two of said passes in a hydrogen atmosphere.
Claim 5
Dependent Claim
14 words
The method as specified in claim 1, wherein said metal mass is refractory metal.
Claim 6
Dependent Claim
16 words
The method as specified in claim 6, wherein said refractory metal mass is niobium or tantalum.
Claim 7
Dependent Claim
22 words
The method as specified in claim 6, wherein said hydrogen atmosphere has a dew point temperature of about 20 to 25* C.
Claim 8
Independent Claim
146 words
The method of purifying a self-sustaining elongated mass of metal by repeated electron-beam, zone-refining passes in an electron-beam, zone-refining system, wherein during each pass a limited length portion of said elongated mass is bombarded by a high-intensity electron beam to melt same, and the elongated mass and electron beam are moved relative to one another at a predetermined rate to sequentially melt adjacent limited length portions of said mass, with melted portions of said mass solidifying after bombardment, which method comprises: a. conducting at least one of said zone-refining passes in a hydrogen atmosphere introduced from a separate hydrogen reservoir into said system at a system pressure no greater than about 5 X 10 3 torr which is sufficiently low to prevent the establishment of a hydrogen discharge, b. thereafter repeating at least one additional zone-refining pass in a higher vacuum to remove any residual gas.
Claim 9
Dependent Claim
31 words
The method as specified in claim 9, wherein said hydrogen atmosphere is at a system pressure of from about 1 X 10 4 torr to about 3 X 10 5 torr.
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) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |