Weight Change Mechanism of Lanthanum Strontium Manganite (LSM) During Thermal Cycles

In the current work, the weight change behavior of (La 0.8 Sr 0.2 ) 0.98 MnO 3 ± δ (LSM-20) from room temperature to 1100°C during the thermal cycle experiments in dry air and Ar was comprehensively investigated with SDT, XRD analysis, and CALPHAD. Especially the quantitative Brouwer diagrams help in understanding the defect reactions inside LSM-20. The weight change was attributed mainly to the Schottky defect reaction. The relationship among weight change, molar change, defect reactions, chemical expansion, and phase transformation is discussed in detail. It is proposed that two very close rhombohedral LT and HT perovskites coexist in our thermal cycle temperature range. Also, the role of P(O 2 ) in the thermal cycle shrinkage is discussed.