Kinetics of phase formation in the Ln–O–S (Ln=La,Gd, Y) systems during oxide sulfidation in ammonium thiocyanate vapor

Kinetics and mechanism of phase formation in the Ln–O–S (Ln=La, Gd, Y) systems during Ln₂O₃ sulfidation in ammonium thiocyanate vapor and the identified sequence of transformations of obtained phases in the temperature range 873‐1273 K have been studied. The kinetic dependencies for the reactions involved were fitted by the Jander equation for topochemical heterogeneous reactions with a squared correlation coefficient R²=.99. The reaction rate constants, pre‐exponential factors, and effective activation energies for the reaction formation of compounds have been calculated, and approximate times and low temperatures for the formation of particular phases have been found.