Effect of citric acid on the synthesis of nano-crystalline yttria stabilized zirconia powders by nitrate–citrate process

The role of citric acid on the preparation of nano-crystalline cubic YSZ powder using a citrate–nitrate solution combustion technique is reported. Thermo-gravimetric analyses reveal that the exothermic peak of nitrate–citrate redox reaction disappears with the increase in citric acid content. The crystallite size of the cubic YSZ powder initially increases with the increase in citric acid content and then decreases upon further addition of citric acid. Particle coarsening has been found to significantly increase upon increase in calcination temperature from 650 °C (11.1 nm) to 800 °C (65.3 nm). Transmission electron microscopic studies in conjunction with XRD analyses indicate a low degree of agglomeration in the synthesized powder. Microwave heating of the solution can control the particle size and yield c-YSZ powder having sizes ∼15 nm.