An AES study of the oxidation of polycrystalline zirconium at room temperature and low oxygen pressures

Auger electron spectroscopy has been used to characterize the oxidation of polycrystalline zirconium in an oxygen atmosphere at low pressures (10 −8 ≤ P   o   2≤ 10 −5 Torr) and room temperature after cleaning the surface by Ar + ‐ion bombardment. Quantitative analysis of the oxidation process was performed by using the intensity of the Zr(M 45 N 23 N 45 ) line which is characteristic of the metallic zirconium. It is concluded from this work that oxidation proceeds as follows: (i) dissociative chemisorption for oxygen exposures lower than 2 L; (ii) formation of nuclei of oxide which grow until coalescence for exposures between 2 and 60 L; (iii) thickening of the oxide film grown in the previous stage. A limiting thickness of 1.5–2 nm is estimated.