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

(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.