Method for the freeze-pressure molding of inorganic powders

Abstract

The present invention is concerned with a method of molding inorganic powders, primarily ceramic powders, in which a binder fluid having a specific freezing point, typically water, is added to the powder to be molded to form a mixture, after which a mold having the desired cavity is filled with the said mixture. The mixture is then pressure molded and rapidly cooled, freezing the binder fluid to produce a frozen molded shape, which is then dried to remove the binder fluid and sintered. The amount of the binder fluid of specific freezing point to be added to the said inorganic powder is the minimum amount that will satisfy the dual demands of flowability during molding and shape retention after the removal of the binder fluid, with from 25 to 50 vol % generally being appropriate. Holding is achieved by injection molding, compression molding or other technique in which pressure is applied to the material in the mold. The present invention makes possible the easy and economical mass production of sintered products of complex shape, high dimensional accuracy, and high density using inorganic material.

Dependencies are inferred from the claim text.