Ultra-high entropy rare earth phosphate against environmental corrosion

Environmental particulate deposits are the most severe factor causing high-temperature corrosion failure in advanced structural materials. Yet, the primary mechanisms of molten material corrosion under extreme conditions remain unclear, hindering the development and improvement of new crucial corrosion-resistant materials. “Ultra-high entropy” rare earth orthophosphates (REPOs) are one such promising class of materials. Here, we investigate the high-temperature structural state and properties of a wide range of substitutions involving 15 (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) rare earth elements in phosphates. Using stepwise stoichiometric compositional design, we aim to systematize our understanding of the corrosion resistance behavior of these complexes RE phosphates. We observe that rare earth elements with larger radii yield materials with greater chemical inertness and single-phase materials exhibit the best corrosion resistance. We infer that 1) the proportions of rare earth elements and 2) the phase state of solid solution stoichiometries are the key factors in determining the corrosion resistance of these complex phosphate materials. Corresponding to the results in this study, this dataset contains specific data points corresponding to all graphs. All data have been labeled with the unit of measure and information about the samples to which they belong.