Observation of micro-droplets on metal surface in early atmospheric corrosion

Atmospheric corrosion of metals is mainly controlled by the surface water film. Due to the function such as capillary cohesion, chemistry absorption, physical absorption and so on, moisture condensation still occurs on the metal surface even when relative humidity of air is not saturated. In this work, the formation of micro-droplets for different metals and environments was investigated and the influent factors were also discussed. According to the statistical measurements, changes of the covering range of micro-droplets in different conditions were studied quantitatively. It proved that the relationship between size and corresponding number of droplets generally followed the basic fractal law, and the fractal dimension kept constant.