Corrosivity of environment and the current state of the steel elements at the former Auschwitz concentration camp

Abstract

The objective of this study was to assess corrosivity of the atmospheric environment in the former Auschwitz I and Auschwitz II-Birkenau concentration and extermination camp, and to identify the protective properties of existing corrosion products in order to estimate the actual corrosion rate of original steel elements located there. The current atmospheric corrosivity of the former Auschwitz camp, specified during one year of exposure of steel samples according to the EN ISO 12944-2 (1998) standard, was determined and it can be described as a boundary between the low C2 and medium C3. The steel corrosion rate in these conditions was in the range of 14–34 µm/year with the average rate of 27 µm/year. A layer of corrosion products formed on uncovered original reinforcement steel rods during ca. 70 years of atmospheric exposure was examined in terms of their protective properties with respect to steel. The microstructure, chemical composition, and elemental chemical state were analyzed by means of scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Potentiodynamic polarization and electrochemical impedance spectroscopy methods were employed to investigate the corrosion resistance of the carbon steel covered with a layer of corrosion products. It has been estimated that this layer slows down the corrosion rate of steel by about five times. Hence, it can be concluded that the corrosion rate of the original steel parts under the layer of corrosion products should not exceed 7 µm/year.