The simultaneous TG-DTG-DTA thermoanalytical curves of 13 rare earth (4f) element oxides, namely, CeO2, Dy2O3, Er2O3, Gd2O3, HfO2, Ho2O3, Nd2O3, Pr6O11, Sm2O3, Tb4O7, Tm2O3, Yb2O3 and Y2O3, were recorded with a MOM derivatograph under static air atmosphere over the temperature range from ambient to 1050°C. Only
HfO2, Nd2O3, Pr6O11, Sm2O3 and Tb4O7 showed appreciable weight losses due to the liberation of small amounts of oxygen. X-ray diffractometry was used to identify
the thermal degradation products and their precursors.