Low temperature synthesis of Yb doped SrCeO3 powders by gel combustion process

In this work, SrCe0.9Yb0.1O3−δ powders were synthesized by a gel combustion method which combined gel process and combustion process. The effect of ratio of citric acid to metal cations (C/M), oxidizer and calcination temperature on the properties of powders was investigated in detail. It was found that the extra oxidizer NH4NO3 increased the flame temperature of combustion and thus promoted the formation of SrCeO3. The relative amount of SrCeO3 in powder increased as the C/M ratio increased. The as-ignited powder at 250 °C mainly consisted of the perovskite SrCeO3, i.e. relative amount of 95.2 wt%. The adiabatic flame temperature of the combustion reaction was calculated to be 1903.1 °C, higher than the required formation temperature of 787.2 °C for SrCeO3. Furthermore, the pure perovskite phase powder with agglomerated microstructure and average grain size of 2 μm was obtained after calcination at 1200 °C for 5 h. This heat-treatment temperature is 200 °C lower than the conventional solid state reaction method for SrCe0.9Yb0.1O3−δ preparation.