The oxidation kinetics of spherically shaped palladium powder

The oxidation kinetics of spherically shaped palladium (Pd) powders was inv estigated over the temperature range between 350 and 800 degrees C. Two typ es of Pd powders differing from each other in particle sizes were used in t his study, 0.30 and 0.85 mu m in diameter. The fraction of total oxide form ed was measured in situ by means of a thermobalance method. In this system, the volume of product palladium oxide (PdO) increases significantly vs. th e volume of reactant Pd, and consequently the experimental data were explai ned well by Valensi-Carter equation. Apparent activation energies of oxidat ion for the two types of Pd powders were both estimated to be 140 kJ/mol. ( C) 1999 Kluwer Academic Publishers.