Application of a Kelvin Microprobe to the Corrosion of Metals in Humid Atmospheres

The principle of operation and the design of a scanning Kelvin microprobe for the determination of corrosion potential profiles are described. The profiles of Volta potentials on galvanically coupled metals under humidity films were determined and are compared to profiles for the same metals under dry nitrogen. The relation between the Volta potential and the corrosion potential and some of the difficulties involved in studying corrosion under humidity films are discussed