Eutectoid decompositions in Ce‐containing ABO₃ perovskites: Part II, the case of divorced growth in CeCrO₃

AbstractA eutectoid phase transformation was exhibited by the perovskite CeCrO3 when heated in air. The kinetics of the reaction, microstructure of the product, and mechanisms of the transformation were studied using thermogravimetric analysis, X‐ray and Raman spectroscopy, X‐ray diffraction, and electron microscopy. Fluorite CeO2 and corundum Cr2O3 were formed from the decomposition of CeCrO3. The CeO2 particles were porous and polycrystalline, a consequence of nucleation, growth, and impingent of CeO2 domains on the CeCrO3 particles. Anisotropic growth is indicated by the morphology of the CeO2 grains, while the Cr2O3 particles were single crystals without any crystallographic orientation relationship to the parent phase. Unlike the CeAlO3 eutectoid, the microstructure comprised of CeO2 and Cr2O3 show no characteristics of a microstructure formed by cooperative growth. The disparity between the eutectoid reactions in CeCrO3 and CeAlO3 is attributed to a difference in interfacial energy between the fluorite and sesquioxide phases (i.e., CeO2/Al2O3 versus CeO2/Cr2O3).