Abstract: Dispersions of sinterable powder, for example, of metal or high-melting-point non-metal such as silicon, or a ceramic substance such as silicon carbide, silicon nitride or alumina, are hot injection-molded using a dispersion of the sinterable material in a binder which, like the dispersion, is solid at room temperature and fluid at the temperature of molding, forming a molded product of uniform density. The binder employed contains polystyrene, which forms the predominant weight proportion of the binder, and in lower weight proportion, an organic compound, e.g., diphenyl carbonate, which is solid at room temperature, is soluble in the molten polystyrene, and is more soluble than the polystyrene is in a lower aliphatic alcohol or ketone. After molding, the binder is removed in non-solid form as vapor, or by dissolution in a solvent, or by oxidation to volatile materials, to leave a porous structure of uniform density.

Abstract: A method of making a siliconized silicon carbide article by(i) injection-molding a mixture which comprises a major proportion of silicon carbide particles and a minor proportion of organic binder material, the mixture being flowable under heat and pressure,(ii) heating the molded article thus formed so as to remove the organic binder material from it and obtain a porous silicon carbide body containing elemental carbon, and(iii) impregnating the porous body with molten silicon to convert said carbon to silicon carbide which binds together the original silicon carbide particles,in which step (iii) is carried out by utilizing as a conduit for said molten silicon the sprue that is formed integrally with the injection-molded article in step (i).The method avoids excessive contact between the surface of the porous intermediate shaped body and molten silicon employed for siliconization, and so reduces the possibility of damage to that body while it is in the weakly bonded state.