Contact electroresistance method for in situ investigation of metal surface in electrolytes

A new contact electroresistance (CER) method is developed for studying in s itu the electroresistance of films on metals and its dependence upon the el ectrolyte composition and potential, The method consists of measuring the C ER between two identical metallic specimens, periodically contacted in elec trolyte under potentiostatic control, in particular, between the walls of a fatigue crack in a sample cyclically loaded below the corrosion fatigue cr ack growth threshold. The sensitivity of the method is 10(-9) Omega and its measuring capability comprises CER values from 10(-9) to 10(5) Omega. The CER method can be used for all conducting materials in any electrolyte at a mbient and high temperatures and pressures in a wide region of potentials i ncluding the potentials of intensive evolution of hydrogen or oxygen. The m ethod allows one to determine the electroresistance of films on metals at v ery early stages of water and anion adsorption, formation and destruction o f hydride and oxide films, electrochemical incorporation of cations, electr odeposition of metals and, also to study the kinetics of these processes. A pplication of the CER method for investigating some current problems of the surface electrochemistry (hydrophilicity of metals, hydroxide ion adsorpti on, connection of the latter with electrocatalysis, charge transfer during anion adsorption and others) are discussed with reference to current litera ture. (C) 2001 Elsevier Science B.V All rights reserved.