Evaluation of Residual stresses on the Surface of 3Y-TZP Containing Monoclinic Phase

3Y-TZP materials have been prepared by cold isostatic pressing and sintering at different heating rate up to full density. Tetragonal - monoclinic phase transformation on the surface of the samples was induced by heat treatment in a powder pack of pure zirconia and up to 1400°C at different holding time. The transformation from tetragonal to monoclinic on the surface of sintered 3Y-TZP was induced as a consequence of the diffusion of yttria in the powder of pure zirconia. The transformation proceeded from the surface into the sample to different depth according to the_ different thermal treatments. In this way a functional graded surface containing compressive residual stresses was produced. Raman spectroscopy was used to determine the variation of the residual stress as a function of the depth of the transformation and of the amount of monoclinic phase.