Abstract: Sintered cubic boron nitride consisting of 80 to 20% by volume of the following component (a), with the balance being essentially the following component (b), and a process for producing such nitride are disclosed:(a) cubic boron nitride;(b) a cermet containing the following sub-components (1), (2) and (3):(1) TiC and/or TiC-TiN, part of which may be replaced by a carbide, a nitride, a boride and/or a silicide of a transition metal of the group IVa, Va and VIa of the Periodic Table;(2) Fe, Co and/or Ni; and(3) Mo and/or Mo.sub.2 C.

Abstract: A process for producing silicon carbide heating elements is described comprising:a primary sintering wherein a mixture including SiC powder, boron or a boron compound, and carbon or a carbon compound in specific proportions, is molded and sintered to obtain a sintered product having from 70 to 95% of the theoretical density; anda secondary sintering wherein the sintered product obtained in the primary sintering is further sintered at each temperature from 1,600.degree. C. to 2,200.degree. C. to obtain a sintered product having a density of at least 80% of the theoretical density and a specific resistivity of not more than 1.0 .OMEGA.-cm.