Preparation of calcium-doped lanthanum chromites powders by citric acid-EDTA complexometry

EDTA was used as assistant complexing agent to chelate with calcium ion solely, then mixed with citric acid, so the problem that citric acid chelated with calcium ion poorly was solved, and the three kinds of cation, La3+, Cr3+, Ca3+, were chelated in the gel uniformly and stably. The structure and decomposition of the gel and the morphology of the powder were investigated by ATR, TG, DSC, XRD and TEM. The perovskite phase La0.9Ca0.1 CrO3 was formed by decomposition of the dried gel at 500°C, 200°C lower than citric acid gel system. Our investigation also showed that calcium doping played an active role in restraining the volatilization of chromium during the gel calcination.