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US4731111A
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Hydrometallurical process for producing finely divided spherical refractory metal based powders
Assignee: Osram Sylvania Inc
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Filing: 1987-03-16
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Granted: 1988-03-15
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Expires: 2007-03-16
Abstract
Abstract A process for producing finely divided spherical refractory metal based powders comprises forming an aqueous solution containing at least one refractory metal, forming a solid reducible refractory metal based material containing a compound selected from the group consisting of refractory metal salts, refractory metal oxides, hydroxides and mixtures thereof, reducing the solid material to refractory metal based powder particles, subjecting the refractory based metal particles to a high temperature zone to melt a portion of the particles and cooling the molten material to form essentially spherical refractory metal based powder particles.
Inventors
- 👤 Nelson E. Kopatz
- 👤 Walter A. Johnson
- 👤 Joseph E. Ritsko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:12
CPC Classifications
B; B22; B22F; B22F1/00; B22F1/06; B22F1/065
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
137 words
A process comprising: (a) forming an aqueous solution containing at least one refractory metal, (b) forming a solid reducible material having a major portion selected from the group consisting of reducible refractory metal salts, oxides and mixtures thereof, (c) reducing said solid reducible material to form refractory metal based powder particles, (d) entraining at least a portion of said refractory metal particles in a carrier gas, (e) feeding said entrained particles and said carrier gas into a high temperature zone and maintaining said particles in said zone for a sufficient time to melt at least about 50% by weight of said particles, and to form droplets therefrom and (f) cooling said droplets to form refractory metal based metallic particles having essentially a spherical shape and a majority of said particle having a size less than 20 micrometers.
Claim 2
Dependent Claim
137 words
A process comprising: (a) forming an aqueous solution containing at least one refractory metal, (b) forming a solid reducible material having a major portion selected from the group consisting of reducible refractory metal salts, oxides and mixtures thereof, (c) reducing said solid reducible material to form refractory metal based powder particles, (d) entraining at least a portion of said refractory metal particles in a carrier gas, (e) feeding said entrained particles and said carrier gas into a high temperature zone and maintaining said particles in said zone for a sufficient time to melt at least about 50% by weight of said particles, and to form droplets therefrom and (f) cooling said droplets to form refractory metal based metallic particles having essentially a spherical shape and a majority of said particle having a size less than 20 micrometers.
Claim 3
Dependent Claim
14 words
A process according to claim 1 wherein said solution contains a water soluble acid.
Claim 4
Dependent Claim
22 words
A process according to claim 2 wherein said mineral acid is selected from the group consisting of hydrochloric, sulfuric and nitric acids.
Claim 5
Dependent Claim
13 words
A process according to claim 3 wherein said mineral acid is hydrochloric acid.
Claim 6
Dependent Claim
15 words
A process according to claim 3 wherein said solid reducible material is formed by evaporation.
Claim 7
Dependent Claim
29 words
A process according to claim 3 wherein said solid reucible material is formed by adjusting the pH to form the solid which is separated from the resulting aqueous phase.
Claim 8
Dependent Claim
17 words
A process according to claim 3 wherein said high temperature zone is created by a plasma touch.
Claim 9
Dependent Claim
14 words
A process according to claim 3 wherein said carrier gas is an inert gas.
Claim 10
Dependent Claim
15 words
A process according to claim 3 wherein essentially all of said metallic particles are melted.
Claim 11
Dependent Claim
47 words
A powdered material consisting essentially of spherical particles of a refractory metal based material, said powdered material being essentially free of elliptical shaped material and essentially free of elongated particles having rounded ends, said powdered material having an average particle size of less than about 20 microns.
Claim 12
Dependent Claim
47 words
A powdered material consisting essentially of spherical particles of a refractory metal based material, said powdered material being essentially free of elliptical shaped material and essentially free of elongated particles having rounded ends, said powdered material having an average particle size of less than about 20 microns.
Claim 13
Dependent Claim
27 words
A powdered material of claim 10 wherein said refractory metal based material is a metal selected from the group consisting of tungsten, molybdenum, niobium, tantalum, and rhenium.
Claim 14
Dependent Claim
32 words
A powdered material of claim 10 wherein said refractory metal based material is an alloy selected from the group consisting of tungsten alloys, molybdenum alloys, niobium alloys, tantalum alloys, and rhenium alloys.
Claim 15
Dependent Claim
41 words
A powdered material of claim 10 wherein said refractory metal based material is selected from the group consisting of tungsten metal, tungsten heavy alloys, molybdenum alloys containing of titanium, zirconium, and hafnium, tungsten alloyed with rhenium, and molybdenum alloyed with rhenium.
Claim 16
Dependent Claim
23 words
A powdered tungsten based material consisting essentially of spherical tungsten based powder, particles of an average size of less than about 20 microns.
Claim 17
Dependent Claim
23 words
A powdered tungsten based material consisting essentially of spherical tungsten based powder, particles of an average size of less than about 20 microns.
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) | 1991-03-15 | 1991-09-14 | 1992-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-15 | 1995-09-14 | 1996-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-15 | 1999-09-14 | 2000-03-15 | $7700.00 | Window Closed / Lapsed |