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.