Impact of sandblasting on the mechanical properties and aging resistance of alumina and zirconia based ceramics

Bioinert zirconia and alumina ceramic devices are widely used, both in orthopaedics and in dentistry. In order to improve their bonding with bone tissues or dental resin cements, their surfaces are often roughened at different scales. In this work, we have investigated the effects of the same sandblasting treatment on alumina, zirconia and a zirconia-toughened alumina, focusing on their mechanical performance and the interplay between surface defects and residual stresses. Additionally, we explored the impact of the treatment on the hydrothermal aging of the two zirconia-containing materials. Residual stresses generated during sandblasting were always predominant over surface defects but their effect varied with the material: while they had a weakening effect on alumina, they reinforced both zirconia-containing materials. Finally, we found that the monoclinic grains at the surface of sandblasted zirconia recrystallized into tetragonal nanograins after annealing and this led to an increased resistance to aging.