Phase transformation and subsurface damage in 3Y-TZP after sandblasting

Objective. The goal of this work is to investigate t-m phase transformation, and subsurface damage in 3Y-TZP after sandblasting. Methods. Commercial grade 3Y-TZP powder was conventionally sintered and fully dense specimens were obtained. Specimens were sandblasted using different particle sizes (110 and 250 mu m) and pressures (2 and 4 bar) for 10s. Phase transformation was measured on the surface and in the cross-section using X-ray diffraction and micro Raman spectroscopy, respectively. Subsurface damage was investigated on cross-sections using SEM and in shallow cross-sections machined by focused ion beam. Results. Sandblasting induced monoclinic volume fraction is in the range of 12-15% on the surface. In the cross-section, a non-homogeneous phase transformation gradient is found up to the depth of 12 +/- 1 mu m. The subsurface damage observed was plastic deformation in grains with the presence of martensite plates, and this effect is found to be larger in specimens sandblasted with large particles. Significance. The extent of subsurface tetragonal-monoclinic transformation and damage induced by sandblasting are reported for different sandblasting conditions. This knowledge is critical in order to understand the effect of sandblasting on mechanical properties of zirconia used to fabricate dental crowns and frameworks. (C) 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.