US4047933A
Expired / Lapsed
US
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Porosity reduction in inert-gas atomized powders
Assignee: Huntington Alloys Corp
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Filing: 1976-06-03
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Granted: 1977-09-13
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Expires: 1996-06-03
Abstract
Abstract Thermally induced porosity, which can lead to cracking in metal powders after consolidation, is believed to be caused by the entrapment of the inert gas used for atomization within the metal powders. The addition of an activating agent to the molten alloy prior to atomization with an inert gas, such as argon, serves to substantially reduce the porosity of metal powders. Suitable activating agents are characterized by an ability to rapidly diffuse to the surface of a molten metal particle and an affinity for oxygen. Activating agents that are useful for high nickel alloys and highly alloyed steels include magnesium, calcium, lithium, silicon, and rare earths.
Inventors
- 👤 Jay Michael Larson
- 👤 Ian Sidney Rex Clark
- 👤 Robert Cameron Gibson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:07
CPC Classifications
B; B22; B22F; B22F9/00; B22F9/02; B22F9/06; B22F9/08; B22F9/082
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
68 words
A process for substantially reducing gas entrapment in an inert gas atomized metal powder comprising: melting a metal alloy, activating said metal alloy by addition of from about 0.001 to about 0.1% by weight of an activating agent, selected from the group consisting of magnesium, calcium, lithium, silicon, and rare earths and atomizing said metal alloy containing said activating agent by contact with a high velocity inert gas.
Claim 2
Dependent Claim
68 words
A process for substantially reducing gas entrapment in an inert gas atomized metal powder comprising: melting a metal alloy, activating said metal alloy by addition of from about 0.001 to about 0.1% by weight of an activating agent, selected from the group consisting of magnesium, calcium, lithium, silicon, and rare earths and atomizing said metal alloy containing said activating agent by contact with a high velocity inert gas.
Claim 3
Dependent Claim
28 words
A process as defined in claim 1, wherein said activating agent is present in said gas atomized metal powder in an amount from about 0.007 to about 0.08%.
Claim 4
Dependent Claim
13 words
A process as defined in claim 1, wherein said activating agent is magnesium.
Claim 5
Dependent Claim
13 words
A process as defined in claim 1, wherein said activating agent is calcium.
Claim 6
Dependent Claim
15 words
A process as defined in claim 1, wherein said high velocity inert gas is argon.
Claim 7
Dependent Claim
24 words
A process as defined in claim 5, wherein said metal alloy is selected from the group consisting of high-nickel alloys and highly alloyed steel.
Claim 8
Dependent Claim
33 words
A process as defined in claim 6, wherein said metal alloy is heated to a temperature that is from about 85° to about 135° C above the melting point of said metal alloy.
Claim 9
Dependent Claim
78 words
A process as defined in claim 7, wherein said metal alloy is a high-nickel alloy containing from about 10 to about 30% chromium, up to about 50% iron, up to about 20% cobalt, up to about 30% molybdenum, up to about 12% tungsten, up to about 8% tantalum, up to about 7% aluminum, up to about 5% titanium, up to about 4% columbium, up to about 0.1% boron, up to about 0.1% zirconium, and the balance essentially nickel.
Claim 10
Dependent Claim
57 words
An inert gas atomized metal powder containing, in weight percent, less than about 0.03% of an atomizing gas, and from 0.001 to about 0.1% of at least one activating agent selected from the group consisting of magnesium, calcium, lithium, silicon, and rare earths, said at least one activating agent concentrated on the surface of said metal powder.
Claim 11
Dependent Claim
57 words
An inert gas atomized metal powder containing, in weight percent, less than about 0.03% of an atomizing gas, and from 0.001 to about 0.1% of at least one activating agent selected from the group consisting of magnesium, calcium, lithium, silicon, and rare earths, said at least one activating agent concentrated on the surface of said metal powder.
Claim 12
Dependent Claim
32 words
An inert gas atomized metal powder as defined in claim 9, wherein said gas atomized metal powder is an alloy selected from the group consisting of high-nickel alloys and highly alloyed steels.
Claim 13
Dependent Claim
107 words
An inert gas atomized metal powder as defined in claim 10, wherein said metal powder is a nickel-base alloy containing from about 10 to about 30% chromium, up to about 50% iron, up to about 20% cobalt, up to about 30% molybdenum, up to about 12% tungsten, up to about 8% tantalum, up to about 7% aluminum, up to about 5% titanium, up to about 4% columbium, up to about 0.1% boron, up to about 0.1% zirconium, from about 0.001 to about 0.1% of at least one activating agent selected from the group consisting of magnesium, calcium, lithium, silicon, and rare earths, and the balance essentially nickel.
Claim 14
Dependent Claim
17 words
An inert gas atomized metal powder as defined in claim 11, wherein said atomizing gas is argon.
Claim 15
Dependent Claim
16 words
An argon atomized metal powder as defined in claim 12, wherein said activating agent is magnesium.
Claim 16
Dependent Claim
16 words
An argon atomized metal powder as defined in claim 13, wherein said activating agent is calcium.
References Cited (Backward Citations)
US3907552A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |