The assessment of natural atmosphere corrosivity by the use of electrochemical noise analysis

Abstract

PurposeThe aim of this work is to evaluate the electrochemical noise (EN) method as a way of evaluating quickly the aggressiveness of natural atmospheres.Design/methodology/approachWire‐on‐bolt tests were used, which implies an exposure of at least three months of bimetallic specimens such as aluminium wire/steel bolt and aluminium wire/copper bolt (CLIMAT units). Electrochemical noise measurements (ENM) also were used.FindingsEN is a powerful tool in the assessing of aggressiveness of atmospheres in short time exposure. Statistical analyses of EN were carried out and provided clear differences between atmospheres depending on pollutants. Results of noise resistance (Rn), root mean square of current (Irms) and localization index are discussed.Research limitations/implicationsThe possible application of ENM to atmospheric corrosion is interesting from a practical point of view. However, more experiments are necessary in order to test a wide range of atmospheres.Practical implicationsEN has proved to be a useful tool when localised corrosion is detected and the presence of chlorides in atmospheres, due to sea fog, results in pitting on the metallic samples.Originality/valueIllustrates that electrochemical noise can be a powerful tool for assessing the aggressiveness of natural atmospheres.