Preparation of YZT a mixed conductor by microwave processing: A different mechanism in the solid state thermochemical reaction

The addition of TiO2 to the 8YSZ system causes the formation of titania-doped YSZ, i.e., YZT and titania-doped YTZP also. The formation of cubic YZT and YTZP depends upon the concentration of TiO2 added to the 8YSZ system. Also, the addition of TiO2 after a critical concentration to 8YSZ system leads to the precipitation of ZrTiO4 as an impure phase in YZT. In the present work, conventional and microwave sintering of YZT of composition [(ZrO2)0.92(Y2O3)0.08](1-x) (TiO2)x where x = 0.00, 0.03, 0.06, 0.09, 0.12 and 0.15, have been prepared. The products were characterized by XRD, SEM and micro Vickers indentation to examine phase composition, surface morphology and mechanical properties respectively. It was observed that during microwave processing stabilization of YSZ occurred after addition of 3% of TiO2 at 1400 °C within 30 min while during conventional processing the stabilization of YSZ occurred after addition of 9% of TiO2 at the same temperature in 10 h. Further, ZrTiO4 an impurity precipitates during conventional processing while ZrTiO4 does not precipitate in the YZT prepared by microwave processing.