Densification strain rate in sintering of Tho2 and ThO2-0.25% Nb2O5 pellets

The densification behavior of ThO2 and ThO2 containing 0.25%Nb2O5 powder compacts was studied with the help of a high temperature push-rod type dilatometer. From the temperature versus density plots, densification strain rate, (1/?)(d?/dt), were calculated. It was observed that the addition of Nb2O5 to ThO2 has caused a drastic increase in densification strain rate in the density range of 76 to 82% of T.D. A five-fold increase in the values of strain rate for ThO2-0.25%Nb2O5 in comparison to pure ThO2 was observed in the temperature range of 1300 to 1350oC. The decrease in the densification strain rate for ThO2- 0.25% Nb2O5 (composition in wt%) at high densities may be attributed to the grain size effect.