Hot-pressing of shapes of non-uniform cross-sectional thickness

Abstract

Uniaxial hot-pressing of ceramic powders to produce monolithic shapes of non-uniform thickness is accomplished by employing a form, preformed to a shape which when properly oriented and uniaxially compressed to final density will deform orderly to assume the final desired shape, and hot-pressing it in a mold against preformed parts having surfaces exactly mating with the surfaces of the preform. Such mold parts have the same compaction ratio as the preform, and a coefficient of thermal expansion substantially equal to that of the preform, and are formed of a powdered composition which is non-reactive with the preform material under hot-pressing conditions. Suitable compositions for the mold part preforms are temporarily bonded mixtures of carbon or graphite powder and a powder material of the preform. The shapes may be slip cast or cold pressed and temporary binders of organic or inorganic material may be employed to give green strength to the parts.

Dependencies are inferred from the claim text.