**4. Conclusions**

Performed jet-impact cavitation test of a group of ceramic materials confirmed their relatively high resistance for cavitation erosion. Test revealed differences between mechanisms of degradation of materials subjected to cavitation and differences in measured wear rates.

Oxide materials degradation consisted in the whole grains removing from the bulk. Silicon nitride material eroded by faster degradation of amorphous phase which was the remnant of sintering process. Silicon carbide destruction is run by grain cracking and fragmentation.

Degradation of all oxide materials started relatively fast and proceeded in accelerated manner during the whole test. Contrary to that, non-oxide materials had a period of stability when any measurable mass losses were detected. After this period materials eroded in a stable manner, independently on test duration.

Composites in alumina/zirconia system have much better resistance for cavitation wear than alumina or zirconia monophase materials. This improvement could be described to profitable microstructural changes (finer grain size) and the presence of residual stresses which locally interact with stresses caused by cavitation.
