Influence of Thermal Treatment on Zirconia Powder

Résumé

Zirconia powder in amorphous state was prepared by electrolytic deposition method (ELD) and then it was subjected to a thermal treatment according to a typical diagram. The structural changes in zirconia powder induced by thermal treatment have been pointed out by X-Ray diffraction (XRD), thermogravimetric analysis (TGA) and differential thermoanalysis (DTA) techniques. During thermal treatment, XRD patterns and DTA curves showed the presence of a mixture of two crystalline phases well-formed at approximately 400 ^oC and a transformation of the type tetragonal-monoclinic (t→m) at approximately 600 ^oC. In situ XRD study allowed establishing the growth kinetics of crystalline phases. Using experimental maximum intensities, H_(hkl) and integral intensities, I_(hkl), of XRD peaks, the volume fractions, V_m, and V_t, of m and t phases, respectively, present in a polymorphic mixture were calculated.