TY - JOUR A1 - Mundhenk, N. A1 - Huttenloch, P. A1 - Bäßler, Ralph A1 - Kohl, T. A1 - Steger, H. A1 - Zorn, R. T1 - Electrochemical study of the corrosion of different alloys exposed to deaerated 80 °C geothermal brines containing CO2 JF - Corrosion science N2 - Corrosion of metallic engineering materials accounts for problems during geothermal operation in the Upper Rhine Graben (URG). Herein, we study the electrochemical behaviour of various metal alloys in an 80 °C simulated geothermal environment by using potentiodynamic polarisation and open-circuit potential measurements. Two different natural geothermal waters from URG geothermal sites were used for the experiments. The measurements reveal spontaneous passivation to be a key process for all alloys. This ennoblement protects more noble alloys from significant corrosion (e.g. titanium gr. 2, alloy 625) and brings less noble alloys to failure, mostly due to pitting corrosion (e.g. 316L). KW - A. Alloy KW - B. Polarization KW - C. Passivity KW - C. Pitting corrosion KW - C. Repassivation KW - C. Thermodynamic diagrams PY - 2014 DO - https://doi.org/10.1016/j.corsci.2014.03.027 SN - 0010-938X VL - 84 SP - 180 EP - 188 PB - Elsevier Ltd. CY - Orlando, Fla. AN - OPUS4-30634 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sarmiento Klapper, Helmuth A1 - Goellner, J. A1 - Burkert, Andreas A1 - Heyn, Andreas T1 - Environmental factors affecting pitting corrosion of type 304 stainless steel investigated by electrochemical noise measurements under potentiostatic control JF - Corrosion science N2 - Electrochemical noise measurements on anodically polarised type 304 stainless steel surfaces in contact with buffer solutions of neutral pH were performed to study the effect of chloride ions in the nucleation of pitting corrosion. Passive layer stability and susceptibility to pitting corrosion after pickling and passivation at different environmental conditions were also investigated by means of electrochemical current noise measurements under cathodic and anodic polarisation. According to the obtained experimental results pits nucleate independently on the presence of chloride ions. It has been also shown that protectiveness of stainless steel surfaces after pickling strongly depends on the relative humidity of the environment in which the surface is subsequently passivated. KW - A. Stainless steel KW - C. Pitting corrosion KW - C. Passivity KW - B. Potentiostatic PY - 2013 DO - https://doi.org/10.1016/j.corsci.2013.06.005 SN - 0010-938X VL - 75 SP - 239 EP - 247 PB - Elsevier Ltd. CY - Orlando, Fla. AN - OPUS4-29662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -