Noise diagnostics at corrosion processes part 1: evaluation of a round robin test

摘要

The Institute of Materials Engineering and Materials Testing of the University of Magdeburg (IWW)organised a round robin test on the measurement of electrochemical noise (EN) and obtained theparticipation of 17 organisations (universities, commercial firms, R&D laboratories) from 5 countries.The experiment involved the investigation of EN signals from aluminium and stainless steel exposedunder conditions in which pitting corrosion can occur. The data provided by the participants wereanalysed at IWW according to various criteria. Evaluation methods included visual inspection of thenoise in the potential or current versus time curves, calculation of the standard deviation, counting oftransients and transformation of the measurements into the frequency domain. Almost all of theparticipants were able to detect differences in EN behaviour during different stages of the experimentqualitatively. Quantitative evaluation, however, revealed a more complex situation. At times,differences in measured EN signal intensity of two orders of magnitude were obtained as a result ofdifferent apparatus used (sensitivity, frequency range, etc.). Nevertheless, the fact that more than halfof the participants reported data within a relatively narrow scatterband is a positive result. Theexperience gained from the round robin test provides a basis for further development of EN as a toolboth for the fundamental understanding of various aspects of corrosion and for the solution ofpractical problems of corrosion protection, in particular in the area of corrosion monitoring.