The amount of water sorption of an epoxy coating can be determined approximately by measuring the electrochemical impedance spectra of both an Al electrode coated with the epoxy film and a preliminary wetted Al electrode covered tightly with the epoxy film. By comparing the double layer capacity of these two electrodes, the amount of water sorption can be estiinated. The resistivity of the electrolytic solution in the film may by thousands times larger than that of the bulk solution. This is due to the fact that the cross-section area of the water passages in the film is of molecular size. The short-distance interaction between the ions and the wall of the water passage retards the transport of the ions seriously. The structure of the water passages is discussed.
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机译:通过椭圆光度法和电化学阻抗谱表征铁铬合金上的被动膜(Karakterisering van de passieve Film op Ijzerchroom Legeringen遇到了Behulp van Ellipsometrie en Elektrochemische Impedantie-spectroscopie)