Experimental studies of salts removal from metal surfaces by wind and rain

This paper outlines an experimental programme aimed at determining the mechanisms of salt removal from metallic surfaces by wind and rain. The paper provides data and process understanding that will be integrated into a holistic model of atmospheric corrosion. Experiments are reported in which fine salt crystals were deposited either wet (as fine droplets of seawater) or dry onto a surface. The surfaces were then placed in a wind tunnel and salt loss was determined as a function of wind speed. In another experiment, the motion of simulated raindrops falling onto metal plates was determined. Finally, in a third series of experiments, video footage of simulated rain on metal surfaces was studied in order to determine both the subsequent motion of rain and its cleaning efficiency. The efficiency of surface cleaning by wind and rain, as determined by these experiments, was then related to Australian climatic conditions. A future paper will present mathematical models of the processes defined in this paper.