Method of producing a conductive silicon carbide-based sintered compact

Abstract

A process is described for producing a conductive sintered body based on silicon carbide, in which a) silicon carbide particles, optionally pretreated with a surface modifier, are dispersed in an aqueous and/or organic medium and positive or negative surface charges are generated on the silicon carbide particles by adjustment of the pH of the dispersion obtained; b) carbon black and boron carbide are mixed in as sintering aids, where at least the carbon black particles have a surface charge opposite to the surface charge of the silicon carbide particles and the boron carbide can also be added, completely or in part, at a later point in time (stage c′)); c) the slip thus obtained is shaped directly to form a green body or c′) a sinterable powder is isolated from the slip obtained and is shaped to form a green body, where the above boron carbide can also be added to this sinterable powder; and d) the green body obtained is subjected to pressureless sintering to form a sintered body in essentially three successive steps, namely (i) preheating to 1200-1900° C. in a nitrogen containing atmosphere (ii), sintering at 1900-2200° C. in a noble gas atmospher and (iii) post-heating at 2150-1850° C. and subsequent cooling to ambient temperature in an atomosphere containing nitrogen and/or carbon monoxide.

Dependencies are inferred from the claim text.