Method of creating porous structures by particle expansion

Patent metadata

Field	Value
Publication number	US-10640848-B2
Application number	US-201916241345-A
Country	US
Kind code	B2
Filing date	Jan 7, 2019
Priority date	Jul 28, 2014
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A process for producing a metal foam. The process includes mechanically working a metallic powder such that oxide particles and/or dissolved oxygen are finely dispersed within a metallic matrix of the metallic particles that make up the metallic powder. The mechanically worked metallic powder is then annealed in a reducing atmosphere, where the reducing atmosphere is an atmosphere that results in the reduction of oxide and/or dissolved oxygen into vapor or gas molecules such that intraparticle porosity is formed within the metallic matrix by conversion of the oxide particles and/or dissolved oxygen to create vapor or gas molecules.

First claim

We claim:

1. A process for producing a metal foam comprising:
mechanically working a metallic powder such that oxide particles and/or dissolved oxygen are finely dispersed within a metallic matrix;
annealing the mechanically worked metallic powder in a reducing atmosphere, the reducing atmosphere being an atmosphere that results in the reduction of oxide and/or dissolved oxygen into vapor or gas molecules such that porosity is formed within the metallic matrix; and
forming the metal foam of the annealed metallic powder having intraparticle porosity formed by conversion of the oxide particles and/or dissolved oxygen to create vapor or gas molecules.

2. The process of claim 1 , wherein the metallic powder is a silver containing metallic powder.

3. The process of claim 1 , wherein the mechanical working is ball milling the metallic powder.

4. The process of claim 3 , wherein the metallic powder is a copper containing metallic powder.

5. The process of claim 4 , wherein the ball milling alloys copper particles with non-copper particles.

6. The process of claim 5 , wherein the non-copper particles are antimony particles.

7. The process of claim 3 , wherein the ball milling, is cryogenic ball milling.

8. The process of claim 3 , wherein the ball milling is room temperature ball milling.

9. The process of claim 1 , wherein the reducing atmosphere is an inert atmosphere.

10. The process of claim 1 , wherein the annealing occurs at a temperature less than or equal to 800° C.

11. The process of claim 9 , wherein the annealing occurs at a temperature less than or equal to 700° C.

12. The process of claim 10 , wherein the annealing occurs at a temperature less than or equal to 600° C.

13. The process of claim 1 , further comprising compacting the annealed ball milled metallic powder into a desired shape.

14. The process of claim 13 , wherein the desired shape has a porosity of at least 40%.

15. The process of claim 14 , wherein the porosity is at least 50%.

16. The process of claim 15 , wherein the porosity is at east 60%.

17. The process of claim 16 , wherein the porosity is at least 65%.

18. The process of claim 1 , further comprising the step of sintering the annealed mechanically worked metallic particles into a desired shape.

19. The process of claim 18 , wherein the desired shape has a metal foam structure and a porosity of the metal foam structure after foaming is at least 40%.

20. The process of claim 19 , wherein the porosity of the metal foam structure after foaming is at least 60%.

Assignees

• Millersville Univ Of Pennsylvania
• Us Army

Inventors

• Atwater Mark Andrew
• Darling Kris Allen
• Tschopp Jr Mark Allen

Classifications

• B22F2009/043

  by ball milling · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• C22C1/08 Primary

  Alloys with open or closed pores · CPC title

• B22F2999/00

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

• B22F3/1143

  involving an oxidation, reduction or reaction step · CPC title