Surface modification with cerium oxide of tetragonal zirconia polycrystals stabilised with 3 % molar yttria (3Y-TZP) has been investigated in order to avoid low temperature degradation. The surface modification was performed by annealing 3YTZP with surface coated CeO2 powder at temperatures of 1400 ºC and 1500 ºC for periods of time up to 10 hours. These heat-treatments diffused cerium up to about 10 mm depth. The bulk fracture toughness, Vickers hardness and Young modulus of the surface modified specimens showed no significant deviation as compared to the nontreated original material. Even the surface mechanical properties measured by penetration curves corresponding to nanoindentations of up to 2 mm depth, did not show significant differences after surface modification. All heat-treatments produced an increase in the surface grain size and a large increase in resistance to degradation.

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