A NOVEL METHOD FOR THE STUDY OF THE EFFECTS OF CL- IONS ON PASSIVATION USING THE CL-36 STAR RADIOISOTOPE - APPLICATION TO THE PASSIVATION OF NICKEL

A novel method has been developed for the in situ investigation of the interactions of Cl−with metal surfaces. The amount of chlorides at the surface is measured by a radiotracer method, using Cl36 radioisotope. The principle of the method is to detect, at the back of the electrode, the electrons which are emitted by adsorbed Cl− or Cl− incorporated in a surface film. The experimental setup allows simultaneous radiochemical and electrochemical measurements to be performed on polycrystal or single-crystal materials. Surface concentrations of chlorides in the range of the submonolayer up to chloride films can be quantitatively measured. The power of this novel method is illustrated by a study of the surface concentration of Cl− on nickel in the active and passive regions in 0.05M H2SO4 + 5 × 10−3M (Cl−). © 1990, The Electrochemical Society, Inc. All rights reserved.