The effect of microstructure on the doped lanthanum zirconates transport properties

Abstract

In this work, materials based on lanthanum zirconates with a pyrochlore structure were prepared by a deposition with ultrasonic spraying. This method combines good variability and scalability. Various approaches to modernize the microstructure of samples and to reduce sintering temperature were applied. For instance, the use of small amounts of sintering additive 0.5 wt.%Co₃O₄ showed an excellent result. In this case, the optimal combination ratio of density and the lowest possible sintering temperature of ceramics has been achieved. The effect of density changes of 3% and 5% on the La_1.95Ca_0.05Zr₂O_7-δ ion transport has been established. The Ca²⁺ segregation reproduced for all samples has confirmed the predominant disordering at grain boundaries in lanthanum zirconates. The proposed synthesis option ensures the specified distribution of elements, claimed dopant solubility and does not transform the defect formation of La_1.95Ca_0.05Zr₂O_7-δ. Hence, the proposed synthesis method can be successfully recommended for the synthesis of ion-conducting rare earth elements zirconates.