An X-ray photoelectron spectroscopy study of the stability of ZrO films on Pd 110/

Thermal stability of ZrO2 overlayers on a Pd 110.substrate is studied using X-ray photoelectron spectroscopy XPS.. The stoichiometric ZrO films, produced in situ by oxidation of physical vapour deposited Zr metal, are stable in 1=10y6 2 Torr of oxygen up to 1000 K. Under vacuum conditions, the oxide films are found to decompose at temperatures above 840 K, resulting in the formation of Zr–Pd alloy. The decomposition of ZrO2 is found to take place at the oxide-Pd interface and the rate limiting step is the release of oxygen through the boundaries between small oxide crystallites. q1999 Elsevier Science B.V. All rights reserved.