Abstract
Yttria-rare earth co-doped tetragonal zirconias were prepared by high temperature hydrolysis of at 200°C for 1 h. Different contents of Sm2O3, Gd2O3 and Nd2O3 were separately used as co-dopants. The obtained powders were tested for their stability as a function of heat treatment up to 1200°C. The powders were investigated by DTA, XRD, IR, BET surface area and TEM techniques. Amorphous-like zirconia powders having noticeably high BET surface areas, around 300 m2/gm, were obtained. IR investigations showed metastable tetragonal spectra for all the samples. Semi-rounded and rod-like nanosized particles were observed by TEM for most of the as-prepared powders. The calcined powders displayed patterns and spectra of the stabilized tetragonal phase. 100% stable tetragonal zirconias are obtained for Gd-Y and Nd-Y co-dopings, while about 98% of the tetragonal phase is obtained for the Sm-Y co-doping. The relationship between the conditions of preparation and the obtained results are briefly discussed.
