Net shape hastelloy X made by metal injection molding using an aqueous binder
AssigneeAlliedSignal Inc.
InventorsJerry C. La Salle, Bryan C. Sherman
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Abstract
A molding compound consisting of the nickel superalloy Hastelloy X is used to form net-shape or near net-shape articles. The compound, containing atomized Hastelloy X powder having an average particle size less than about 20 .mu.m, is mixed with a liquid carrier, a gel forming binder and processing additives and molded at relatively low pressures in a conventional injection molding machine. A critical air debinding step prior to sintering results in high densification of the article, which has mechanical properties comparable to cast or wrought processed material.
Claims14
A process for debinding and sintering an article of manufacture made in an injection molding process from Hastelloy X alloy powder and an aqueous binder comprising the steps of:
- a) in an air atmosphere debinding the article by raising the temperature to a value sufficient to decompose the polysaccharide in the aqueous binder;
- and
- b) in a hydrogen atmosphere sintering the article at elevated temperatures to reduce any oxidation formed on the article during the debinding step.
An injection molding process for forming an article from Hastelloy X alloy powder comprising the steps of:
- a) injecting a mixture comprising
- (1) Hastelloy X alloy in powder form, and
- (2) a gel-forming aqueous binder consisting of a polysaccharide material into a mold, the mixture being maintained prior to the injection step at a first temperature above the gel point of the binder;
- b) cooling the mixture in the mold to a second temperature below the gel point of the binder to form a self-supporting article;
- c) debinding the article in an air atmosphere by raising the temperature to a value sufficient to decompose the polysaccharide in the aqueous binder;
- and
- d) sintering the article in a hydrogen atmosphere at elevated temperatures to reduce any oxidation formed on the article during the debinding step.
Dependencies are inferred from the claim text.