Breakdown of Passivity of Nickel by Fluoride: II . Surface Analytical Studies

Passive layers on nickel and their change by the action of fluoride have been studied by surface analyses such as x‐ray photoelectron spectroscopy (XPS) and low energy ion scattering (ISS). The thickness of the layers is deduced from the height of the XPS signals , O1s, and F1s and their attenuation by covering layers. Argon sputtering gives information on the in‐depth structure of the passivating films in combination with XPS and the higher depth resolution of ISS. Their thickness and chemical composition change with the electrode potential and the time of exposure to . A multilayer structure is found with an inner oxide and outer hydroxide film and, in a higher potential range, a fluoride layer in between. The layer structure shows a close correspondence to the results of the electrochemical examination.