Features of the synthesis of magnesium praseodymium hexaaluminate PrMgAl<sub>11</sub>O<sub>19</sub> with a magnetoplumbite structure

RE magnesium hexaaluminates with magnetoplumbite structure are considered as potential candidates for thermal barrier coatings. However, the synthesis of single-phase samples is associated with certain difficulties. In this work, the features of PrMgAl11O19 preparation by reverse precipitation and citrate sol-gel synthesis are compared. Based on the results of thermal analysis of precursors, stepwise annealing of the samples was carried out, followed by X-ray phase analysis of the product. It is shown that the optimal condition for producing single-phase hexaaluminate PrMgAl11O19 is long-term annealing of tableted precursors obtained by the sol-gel method at a temperature of 1600°C. Thermodynamic assessment of possible reactions of praseodymium magnesium hexaaluminate formation from oxides confirmed the decomposition of PrMgAl11O19 at temperatures above 1700°C.