Abstract: The invention relates to a sintered body of a ceramic composite material based on alumina, refractory hard phases and ZrO.sub.2, HfO.sub.2 and/or partially stabilized ZrO.sub.2 with a relative density of more than 98%. The sintered body according to the invention has chromium integrated in amounts corresponding to in all 1-20 weight % and ZrO.sub.2, HfO.sub.2 and/or partially stabilized ZrO.sub.2 present as 2-16 weight % with these latter phases present to more than 70% in the tetragonal crystal modification. Furthermore, the refractory hard constituents are present as particles with a grain size of less than 10 .mu.m and/or as whiskers or fibers with a diameter of less than 5 .mu.m and a length/diameter ratio of >10.