The outdoor performance of printed-circuit iron cells in self-driven operation: Electrochemical and environmental features

Abstract

This paper addresses some aspects of surface wetness, which is a most relevant issue for the decay of materials in the open. The performance of printed-circuit iron cells in self-driven operation under range-simulated saltfall (25 and 400mgm −2 day −1 Cl −) was assessed outdoors by means of zero-resistance ammetry. A 96-hour term at the beginning of each experiment was taken as the test interval for evaluation and comparison purposes. Nonparametric statistics evidence that, despite its magnitude, the output of either cell closely follows the relative humidity and could be of use for searching into temperature effects as well. Statistical significance appears unimpaired by transient (atmospheric) behaviour or by experimental (simulation) procedures. Considering the reliability of electrochemical variates, the ISO-standard TOW (time-of-wetness) looks too conservative, whereas cells almost coincide in both the start-up and duration of surface wetness for corrosion to occur. Galvanic data was found to underestimate true dissolution rates, as expected. However, cell efficiency seems unrelated to the extent of surface contamination and cell rate responds to salinity in a ratio that agrees with previous indoor (R P) measurements.