Passivation and alloying element retention in gas atomized powders

Patent metadata

Field	Value
Publication number	US-11826832-B2
Application number	US-202016873501-A
Country	US
Kind code	B2
Filing date	Apr 22, 2020
Priority date	Jun 20, 2013
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A method for gas atomization of a titanium alloy, nickel alloy, or other alumina (Al2O3)-forming alloy wherein the atomized particles are exposed as they solidify and cool in a very short time to multiple gaseous reactive agents for the in-situ formation of a passivation reaction film on the atomized particles wherein the reaction film retains a precursor halogen alloying element that is subsequently introduced into a microstructure formed by subsequent thermally processing of the atomized particles to improve oxidation resistance.

First claim

We claim:

1. A body made from consolidated titanium-aluminum alloy atomized particles each having, before consolidation, an outer surface layer comprising an outermost oxy-fluoride layer region formed on an innermost oxygen-containing layer region that is formed first by exposure of surfaces of the atomized particles to an oxygen-bearing gas, wherein the body has a microstructure having fluoride of the outermost oxy-fluoride layer region present in the microstructure in an amount to improve oxidation resistance.

2. The body of claim 1 wherein, after consolidation of the atomized particles, fluoride is present in solid solution and/or as a fluoride-enriched precipitate in the microstructure.

3. The body of claim 1 which is thermally processed.

4. The body of claim 3 wherein the thermally processed body exists in at least one condition of being hot isostatic pressed, sintered, hot extruded, and hot metal particle injected.

5. A body made from consolidated nickel-aluminum alloy atomized particles each having, before consolidation, an outer surface layer comprising an outermost oxy-fluoride layer region formed on an innermost oxygen-containing layer region that is formed first by exposure of surfaces of the atomized particles to an oxygen-bearing gas, wherein the body has a microstructure having fluoride of the outermost oxy-fluoride layer region present in the microstructure in an amount to improve oxidation resistance.

6. The body of claim 5 wherein, after consolidation of the atomized particles, fluoride is present in solid solution and/or as a fluoride-enriched precipitate in the microstructure.

7. The body of claim 5 which is thermally processed.

8. The body of claim 7 wherein the thermally processed body exists in at least one condition of being hot isostatic pressed, sintered, hot extruded, and hot metal particle injected.

Assignees

• Univ Iowa State Res Found Inc

Inventors

• Heidloff Andrew J
• Rieken Joel R
• Anderson Iver E

Classifications

• B22F9/082 Primary

  atomising using a fluid (using centrifugal force B22F9/10) · CPC title

• B22F1/16

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title

• B22F2009/0844

  in controlled atmosphere · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title