Abstract: A ceramic cutting tool of a TiC-based sintered body containing 40 wt % or more of TiC, and 5 to 40 wt % of SiC whisker uniformly dispersed in the sintered body, said SiC whisker having a diameter of 0.2-1.5 .mu.m and a length of 1-20 .mu.m. The sintered body may include up to 40 wt % of Al.sub.2 O.sub.3, and may further contain sintering aid.Up to 40% by weight of TiC may be substituted with at least one of Ti, nitrides, oxides and borides of Ti, and solid-solution of said nitrides, oxides and borides of Ti to form a TiC-base composition.The TiC-base composition may be represented by (Ti.sub.a M.sub.b) (C.sub.c N.sub.d O.sub.e B.sub.f).sub.g where: M denotes at least one of transition metal elements of Groups IVa, Va and VIa, except Ti, according to the International Periodic Table; and a+b=1, 0<b.ltoreq.0.5, c+d+e+f=1, 0.5 .ltoreq.c.ltoreq.1.0, 0.ltoreq.d.ltoreq.0.5, 0.ltoreq.e.ltoreq.0.3, 0.ltoreq.f.ltoreq.0.5, 0.6.ltoreq.g.ltoreq.1.1.

Abstract: A ceramic cutting tool formed of a TiC-based sintered body contains 40 wt % or more of TiC, and 5 to 40 wt % of SiC whisker uniformly dispersed in the sintered body. The SiC whisker has a diameter of 0.2-1.5 .mu.m and a length of 1-20 .mu.m. The sintered body may contain up to 40 wt % of Al.sub.2 O.sub.3, and further sintering aids. Up to 40% by weight of the TiC may be substituted with at least one of Ti, nitrides, oxides and borides of Ti, and solid-solutions of these nitrides, oxides and borides of Ti to form a TiC-base composition. The TiC base composition may be represented by the formula (Ti.sub.a M.sub.b) (C.sub.c N.sub.d O.sub.e B.sub.f).sub.g, in which M denotes at least one transition metal element of Groups IVa, Va and VIa according to the International Periodic Table, except Ti; and a+b=1, 0<b.ltoreq.0.5, c+d+e+f=1; 0.5 c.ltoreq.1.0; 0.ltoreq.d.ltoreq.0.5; 0.ltoreq.e.ltoreq.0.3; 0.ltoreq.f.ltoreq.0.5; and 0.6.ltoreq.g.ltoreq.1.1.

Abstract: Highly tough ceramics are produced by:providing a formulation comprised of 20 to 50% by weight of titanium carbide expressed in terms of the general formula TiCx wherein x is 0.65 to 0.93, 0.1 to 2% by weight of one or more sintering aids, and 48-79.9% by weight of Al.sub.2 O.sub.3, andsintering said formulation by the press-sintering process.Alternatively highly tough ceramics are produced by:providing a formulation comprised of 20 to 50% by weight of titanium carbide expressed in terms of the general formula TiCx wherein x is 0.65 to 0.93, 0.05 to 3.0% by weight of one or more rare earth oxides, and 47 tto 79.95% by weight of Al.sub.2 O.sub.3 ;subjecting the formulation to primary sintering in an inert gas until relative theoretical density of 95-99% is achieved, andsintering the resultant mass by the hot isostatic pressing process.