Soluble salts and the durability of paint coatings: A new laboratory method for dosing chlorides and sulphates over steel surfaces

摘要

The presence of soluble salts, especially chlorides and sulphates, at the metal/paint interface usually causes premature deterioration of the paint system. In practice, soluble salts are found heterogeneously distributed in the steel corrosion products layer and are frequently located at the base steel/rust layer interface. However, in most of the research studies carried out with the aim of establishing critical concentration levels for different paint systems, panels have been prepared by dosing the saline contaminant in an uniform way across flat and unrusted steel surfaces. In order to resolve this problem, an attempt has been made to reproduce the atmospheric corrosion process of steel in environments contaminated with SO2 and Cl-, using a salt fog cabinet for the case of chlorides, and a Kesternich type cabinet for sulphates.