Abstract: The present invention is concerned with a ceramic formed body comprising a ceramic matrix and at least one phase of ceramic incorporation material dispersed therein, characterized by a dense, microcrack-free ceramic base matrix and compressive zones incorporated therein which consist of a mixture of the base matrix material with unstabilized zirconium dioxide particles which are predominantly monoclinic at ambient temperature.The present invention is also concerned with a process for the production of such ceramic formed bodies and with the use thereof as constructional elements in the hot region of heat engines.