Process for preparing molded silicon carbide product

Claim 1

A process for preparing a molded silicon carbide product, which process comprises molding a mixture of silicon carbide powder, an organosilicon compound and a lubricant selected from the group consisting of higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher alcohols and paraffin wax into a compact and sintering the compact wherein the lubricant has the following properties: (a) it does not substantially evaporate during such operations as mixing, drying, molding, etc.; (b) it is in liquid or solid form, and when it is a solid, it has a melting point of 40° C. or higher; (c) it exhibits low viscosity in a melt of a mixture of the lubricant and organosilicon compound; and, (d) it undergoes almost complete evaporation at or below a temperature at which the organosilicon compound is pyrolyzed, i.e., at temperatures up to 500° C.; wherein the organosilicon compound is one or more compounds selected from those in which (1) silicon atoms are bonded only to carbon atoms; (2) besides the bonds between silicon atoms and carbon atoms, silicon atoms are bonded to hydrogen atoms; (3) besides the bonds between silicon atoms and carbon atoms, there are bonds formed between silicon atoms and halogen atoms; (4) in addition to the bonds between silicon atoms and carbon atoms, there are bonds established between silicon atoms per se; and (5) there are two or more types of bonds out of the above-mentioned bonds (2) through (4), or a polycondensation product, obtained by polycondensation of these compounds, containing silicon-carbon bonds as its principal backbone structure; and wherein the ratio of lubricant to organosilicon compound is in the range of 0.2 to 1 to 2.0 to 1.