Atmospheric Corrosion of Copper, Interpretation and Modeling

Abstract

Atmospheric corrosion of metals is affected by many factors related to the environment, and the metal as well. Atmospheric corrosion of copper attracts a considerable attention due to the wide application of copper objects in this medium. Copper samples were exposed to the atmospheric attack in 8 testing sites in the R. N. Macedonia over a period of 13 years. The weight loss was measured in increasingly long intervals, as e.g. 3, 6, 12 etc. months. Each specimen served for only one period of exposure. Further treatment of the randomly scattered results followed. The familiar parabolic-like pattern of corrosion rate vs. time plots were registered. The corrosion process course is burdened with the impermeable properties of accumulated corrosion products on top of the copper surface. Interpretation of acquired results was not an easy task due to the intermittent course of process affected by the continuous changes of corrosion affecting parameters (wetness, pollution, sun radiation, etc.). Special attention was paid to the effects of the atmospheric conditions during primal exposure, specimen surface orientation (skyward or groundward), number of duplicated specimen, because they could affects the results. A development of model based on the premise that the atmospheric corrosion of metals is not a smooth and continuous process, but is rather sequentional was performed. Such approach gives possibility to deal with this multivariable phenomenon that ends in scattered data.