Characteristics of YSZ synthesized with a glycine-nitrate process

The amount of glycine addition was optimized for synthesizing (Y2O3)0.08(ZrO2)0.92 (YSZ) powders with a glycine-nitrate process. The effect of glycine quantity was investigated on the phase structure, sintering behavior, electrical performance and microstructure of the resulted YSZ powders. With the increase of glycine addition, the crystallite size of the YSZ powder increased, the specific surface area decreased, and the density of the sintered YSZ pellets decreased when they were fired at the same temperature. Thermodynamic calculation showed that the flame temperature of the glycine-nitrate combustion reaction was much higher when more glycine was used. A highly loose powder was thus obtained with low quantity of glycine addition. When 70% of stoichiometric amount of glycine was used, YSZ powder had the highest densification rate. AC impedance spectroscopy showed that the amount of glycine had effects not only on total conductivity, but also on grain boundary and bulk contributions. The highest conductivity attained a value of 0.027 S cm−1 at 800 °C for YSZ prepared with 80% of stoichiometric amount of glycine.