Study on Sintering Kinetics of (Th_xCe_1-x)O₂ Ceramic Pellets Prepared via Sol-Gel Method

Abstract

(Th_xCe_1-x)O₂ microspheres (x = 0.50, 0.75, and 0.95) prepared by sol-gel microsphere technique were compacted to pellets. The sintering kinetics, diffusion mechanism, and activation energy of the (Th_xCe_1-x)O₂ pellets were investigated by dilatometry for 1100°C, 1200°C, and 1300°C. The rate controlling sintering method, one of the most sensitive methods, was chosen to investigate the sintering kinetics. The pellets were heated with a rate of 10°C/min and were held for 10 h at the above mentioned temperatures under isothermal conditions.

The activation energies for the (Th_0.50Ce_0.50)O₂, (Th_0.75Ce_0.25)O₂, and (Th_0.95Ce_0.05)O₂ pellets were calculated as 305, 315, and 419 kJ·mol⁻¹, respectively. In the experiments, green densities of the mixed-oxide pellets were determined as 45% to 47% of the theoretical density for all of the studied ratios. Sintering densities reached up to 94% of theoretical density after sintering at 1300°C. Scanning electron microscopy images of the pellets were taken.

Keywords:

• Thorium
• cerium
• mixed-oxide fuel

Acknowledgments

We are grateful to the Material Technology Unit of the Çekmece Nuclear Research and Training Center of the Turkish Atomic Energy Authority for their helpful discussion and valuable contribution. This research was supported by the Ege University Research Foundation (grant number 2008 NBE 001).