Sintering and densification behavior of pure and alkaline earth (Ba2+, Sr2+ and Ca2+) substituted La2Mo2O9

The present work studies densification and grain growth of fast oxide ion conductor, lanthanum molybdenum oxide (La2Mo2O9). Sintering variables are experimentally analyzed using sintering laws. This paper investigates sintering of pure as well as Ca2+, Sr2+ and Ba2+ doped compositions by linear shrinkage measurement using dilatometer, relative theoretical density calculation and microstructural analysis using scanning electron microscope. In this work fine powder prepared by citrate–nitrate auto-combustion synthesis is used as source of powders for different compositions. The investigations indicate that sintering is enhanced in compare to the powders prepared by the other synthesis routes reported earlier. The evaluation of activation enthalpy of pure La2Mo2O9 and its dependence with dopant addition are also studied with the help of sintering models and equations. The sintering mechanism is found to be dominated by grain boundary diffusion. The sintering inhibition is observed for the substituted compositions.