Stability of rare earth oxides in a moist environment at elevated temperatures—Experimental and thermodynamic studies: Part II: Comparison of the rare earth oxides

Volatilisation tests enabled to quantify the stability of different rare earth sesquioxides, RE2O3 (where RE = Sc, Dy, Er, Yb) and to understand the corrosion process. These tests were carried out at temperatures ranging from 1000 to 1400 °C in moist air with 50 kPa of water at atmospheric pressure, under a flowing gas velocity of 5 cm s−1. Besides the volatilisation rate, the nature of the volatile gaseous species was determined. The proposed experimental method allowed too to assess the Gibbs free energy of formation of these gaseous volatile species. Finally, the stability of each rare earth oxide under a moist environment at high temperature was compared.