Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy were applied to the study of thin films formed by transpassive dissolution of nickel in a nitrate electrolyte and by exposure of mechanically polished nickel to air. Variation of take-off angle and sputter profiling were used to determine the thickness and chemical composition of these films. Transpassive films are found to be thicker and different in composition than air formed films. Nitrogen present in the metal-oxide interface of the transpassive film is in a reduced state.
Dr. Madhav Datta, Mathieu, H. J., and Landolt, D., “Characterization of transpassive films on nickel by sputter profiling and angle resolved AES/XPS”, Applications of Surface Science, vol. 18, pp. 299–314, 1984.