Corrosion monitoring technique and surface observation method in atmospheric corrosion evaluation

Although it is the problem which makes atmospheric corrosion familiar and has many subjects on the occasion of practical use of materials, conventional electrochemical measurement is difficult to apply to the evaluation. Many measurements have been tried to evaluation of the atmospheric corrosion. In this description, the monitoring technology and the surface observing method in evaluation of atmospheric corrosion was introduced mainly. The effectivity and application limits of exposure tests, ACM sensor method, AC impedance method and QCM were explained as the monitoring technique. The ion penetration resistance measurement and the ion selective permeability evaluation of the rust film on the steel used for atmospheric corrosion evaluation of steel materials was introduced from sample fabrications as experimental method to the analysis. The importance of characteristic of a corrosion product was also explained. Furthermore, the development of surface visualization technology and expectation of application to evaluation of the atmospheric corrosion were indicated by explaining the effectivity of the surface potential measurement using the Kelvin probe method and the AFM as a surface observing method, and the surface pH distribution measurement.