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US 4,233,256 AGranted
Process for injection molding sinterable carbide ceramic materials
AssigneeThe Carborundum Company
InventorRoger W. Ohnsorg
Life of this patent
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Abstract
Ceramic compositions that may be injection molded and subsequently sintered are described. A particulate ceramic material, such as silicon carbide, is coated with a mixture of thermoplastic resin and oils or waxes, and utilized as a feed material in an injection molding process. The molded product may subsequently be sintered at 2000.degree. C. to 2200.degree. C. to produce a hard, dense article.
Claims7
A process for producing a sintered carbide ceramic article comprising the steps of:
- a. forming a homogeneous mixture containing from about 65 to about 86 percent by weight of a sinterable carbide ceramic material;
- from about 0.2 to about 0.5 percent by weight of a sintering aid of boron or beryllium selected from the group of elemental beryllium, beryllium compounds, elemental boron, boron compounds, or mixtures thereof;
- from about 14 to about 30 percent by weight of a mixture of thermoplastic resin and at least one oil or wax having a lower volatilizing temperature than said resin;
- and a carbon source material sufficient to provide from about 0.5 to about 5.0 percent by weight excess carbon,
- b. injection molding said mixture to produce a molded product,
- c. removing said thermoplastic resin by baking said molded product at a temperature between about 450.degree. C. and about 1000.degree. C. to produce a porous baked product, consisting of ceramic material, sintering aid and excess carbon,
- d. sintering said baked product at a temperature between about 2000.degree. C. and about 2200.degree. C. to produce a sintered prduct.
4 more elements
Dependencies are inferred from the claim text.