Characterization of Compactness of Rust Layers on Weathering Steels by an Adsorption/Dehydration Test of Ethanol

A new method for evaluating the compactness of rust layers on steels has been proposed in the present study. The method includes adsorption and dehydration process of anhydrous ethanol. The protective ability of rust layers can be qualitatively reflected by the adsorption/dehydration rates. The specific surface area and porosity of rust layers can be calculated by a quantitative model. The results from the present method are consistent with electrochemical tests, N 2 adsorption and X-ray diffraction analysis. The method characterizes the compactness of rust layers rather than that of corrosion products removed from the metal surfaces, which is generally practiced in classic N 2 adsorption method. Furthermore, the method can reflect the compactness of inner rust layers, to which N 2 adsorption is unavailable. The method provides a new approach for the study of rust layers.