The differnt roles of substoichiometry and transient liquid phase on sintering of ZrO2/TiC with TiH2

Sintering of tetragonal ZrO2 with 35 vol-% TiC is activated by the use of substoichiometric TiC(1-x), but the effect is not sufficiently strong to enable pressureless sintering to high densities. The latter becomes possible by a transient liquid phase generated by a TiH2 additive which enhances the densification in a similar way as MgO/Y2O3. Oxide doping, however, increases the number and the size of amorphous triple junctions, favours the formation of transformation resis- tant t'-ZrO2 and deteriorates strength and toughness.