Method of casting powder materials
AssigneeNKK Corporation
InventorsHiroaki Nishio, Takeshi Kawashima, Yoshio Takagi
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Abstract
A method of casting a powdered material. A slurry is formed by dispersing metal powder or ceramic powder into a dispersing medium mainly consisting of a substance extractable by a liquid or supercritical carbon dioxide and having a melting point between 0.degree. C. and 100.degree. C., and the slurry is poured into a liquid non-absorbing mold where the slurry is cooled to freeze and solidify into a molding. The main constituent of the dispersing medium in the molding is extracted and removed by the liquid or supercritical carbon dioxide.
Claims11
A method of molding metal powder or ceramic powder comprising the steps of:
- forming a slurry by dispersing metal powder or ceramic powder into a dispersing medium mainly consisting of a substance extractable by a liquid or supercritical carbon dioxide and having a melting point between 0 and 100.degree. C.;
- wherein said slurry has a viscosity of from 50 to 144 c poise and wherein the powder concentration of the slurry is from 40 to 75 volume percent and the dispersing medium is from 60 to 25 volume percent;
- pouring said slurry into a liquid non-absorbing mold and applying a pressure of from 0.3 to 10 Kg/cm.sup.2 to said slurry immediately after the pouring thereof and maintaining said pressure;
- cooling said slurry to freeze and solidify to form a molding;
- removing said molding from said mold;
- and
- extracting and removing a major constituent of said dispersing medium by a liquid or supercritical carbon dioxide and wherein the liquid carbon dioxide is exhausted by changing said liquid carbon dioxide from the liquid state to a vapor state so as to form no vapor-liquid interfaces and passing through a region of pressures between 73.8 and 250 atmospheres and temperatures between 31.1.degree. and 100.degree. C.
Dependencies are inferred from the claim text.