Effect of CdO additive on sintering of LiNbO3

Abstract

The effect of CdO additives on the sintering of LiNbO₃ at 805–1100°C was studied and is discussed on the basis of Kingery's model of initial sintering and cubic grain growth kinetics. The sintering appears to be controlled by the volume diffusion of oxygen ion in both cases. Exaggerated grain growth in pure LiNbO₃ occurs at 1050–1100°C and hinders the attainment of sintered densities higher than 83–87%. Addition of CdO increases the diffusion coefficient of oxygen by about 500 times during initial sintering and causes rapid densification. DTA curves indicated a reaction between CdO and LiNbO₃ at 750–895°C; the second phase thus formed probably hinders exaggerated grain growth.