Oxidation of Pd and Pd-RE Alloys

The oxidation of Pd and Pd-RE alloys were studied by recording weight changes as a function of temperature by thermogravimetric analyzer. The alloys studied include PdLa sub 0.58 , PdEu sub 0.3 , and PdGd sub 0.48 . The oxidation process was isothermic in flowing oxygen of 50-60 ml/min. A series of thermal phenomenon such as the formation, decomposition, and evaporation of PdO were observed at 348, 750 and 877 deg C respectively. The oxidation of Pd was found to be a weight-gain process at low temperature, and a weight-loss process at high temperature. The weight gain of PdO was detectable at 348 deg C. The RE additions made the temperatures above characteristic points shift to lower or higher side because of the formation of RE oxides. This reduced the internal oxidation of Pd matrix at high temperature.