Auger electron, electron energy loss and secondary electron emission spectroscopic studies on the oxidation of zirconium at high temperatures and room temperature

Abstract

Auger electron (AES), electron energy loss (EELS) and secondary electron emission spectroscopy (SES) have been used to investigate the surface oxidation of zirconium at room temperature and high temperatures, 773–973 K, under low oxygen pressures 1.3 × 10^–5–1.3 × 10^–3 Pa. The kinetic energies of the Auger and the secondary electrons and the electron energy losses by single electron excitations are explained by the electronic structure in the core and the valence states of the metal and the oxide of zirconium. The energy loss by the collective excitation of plasmon is also observed in the EELS measurement for the metal and the oxide surface. The increase in the relative peak-to-peak height of the oxygen Auger transition and of the zirconium Auger transition by oxidation at high temperatures does not depend simply on the oxygen exposure represented by the product of oxygen pressure and exposure time, i.e. exposure in Langmuir, because of the dynamic competition between surface processes and the diffusion process of oxygen into the bulk. The rate of oxide growth is found to be parabolic at high temperature (773 K) and at 1.3 × 10^–5 Pa.