Phase Transformations in Calcium-Substituted Lanthanum Ferrite
Phase equilibria in the La1−xCaxFeO3−δ (LCF) system were assessed at temperatures below 1350°C in both simulated air and argon atmospheres using a combination of differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and high-temperature X-ray diffraction. The solubility limit of Ca in the perovskite structure was determined to be 38% A-site substitution. A high-temperature orthorhombic to rhombohedral transition was identified and the dependence on oxygen partial pressure and effect on thermal expansion were characterized. A partial, pseudobinary LaFeO3–CaFeO2.5 phase diagram is presented that is based on these analyses combined with data available in the open literature.
Price, Patrick M.; Rabenberg, Ellen; Thomsen, David; Misture, Scott; and Butt, Darryl P.. (2014). "Phase Transformations in Calcium-Substituted Lanthanum Ferrite". Journal of the American Ceramic Society, 97(7), 2241-2248. http://dx.doi.org/10.1111/jace.12891