Low-Temperature Phase Transformation of Lanthanum Chromites Doped withCalcium

摘要

The low-temperature phase transformation of LaCrO3 and doped-LaCrO3 was studied by DSC andXRD, and thermal expansion during phase trans formation was measured. It is found that the phase transformation of LaCrO3 begins near 240℃ and ends up to 265℃. The phase transformation temperature range obviously raises as the Ca content increases. The low temperature transformation changes the crystal structure of LaCrO3 and Ca-doped LaCrO3 from orthorhombic to rhombohedral and is a heat-absorbing reaction.There is no weight change but shrink of the sample happened during transformation.