Microporous metal parts
AssigneeSouthco, Inc.
InventorRatnesh K. Dwivedi
Life of this patent
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Abstract
A metal injection-molding feedstock is heated and plasticized. Supercritical carbon dioxide is injected into the feedstock to form micropores when the pressure is reduced and a parts mold is filled. The micropores are retained when the green parts are debindered and sintered.
Claims15
A microporous metal part comprising:
- a homogeneous interior core of sintered substantially uniformly sized metal powder particles and closed pores;
- and
- a dense outer surface layer of said uniformly sized powder particles substantially without pores extending about said core;
- wherein the closed pores are substantially uniformly sized and uniformly distributed throughout the core, and wherein said closed interior pores are substantially larger than said metal powder particles.
A microporous metal part comprising sintered metal powder having gas formed closed interior pores and having a dense outer surface layer substantially absent of said gas formed closed interior pores, wherein the walls of said gas formed closed interior pores are formed of said sintered metal powder, and wherein said gas formed closed interior pores are substantially uniformly distributed and uniformly sized throughout the interior of said part.
A MIM part having a high proportion of closed interior pores and a good surface finish, comprising:
- sintered metal powder substantially absent of interstitial voids;
- a plurality of closed interior micropores being substantially uniform in size and distributed substantially uniformly throughout substantially the entirety of said sintered metal powder;
- and
- a dense outer surface layer substantially absent of said closed interior micropores.
A microporous part comprising substantially uniformly sized sintered particles and uniformly sized closed pores, and a dense substantially uniformly thick outer surface layer of said sintered particles without said closed pores, said outer surface layer completely surrounding said sintered particles and uniformly sized closed pores, and wherein said closed pores comprise more than 25% of the volume of said part.
A microporous part comprising:
- a homogeneous interior core of a mass of sintered powder particles and closed interior pores formed in said sintered powder particle mass;
- and
- a dense outer surface layer of said sintered powder particle mass substantially without said closed interior pores;
- wherein the closed interior pores are substantially uniformly distributed throughout the part inside the outer surface layer with the walls of said closed interior pores being of said sintered powder particle mass;
- and
- wherein said closed interior pores are substantially larger than said powder particles.
Dependencies are inferred from the claim text.