TY - JOUR A1 - Babutzka, Martin A1 - Müller, Thoralf A1 - Mietz, Jürgen A1 - Burkert, Andreas T1 - Investigation of the influence of iron‐containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4 JF - Materials and Corrosion N2 - The corrosion resistance of aluminium surfaces is closely linked to the surfacecstate after a grinding process. For years, iron‐containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary. For the current investigation, specimens of a technical Al‐Si alloy from the same batch were used. The test specimens were mechanically ground with various resin‐bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron‐containing abrasives on the corrosion behaviour of the Al–Si alloy. However, the most sensitive measuring method (electrochemical noise) showed differences in the surface activity depending on the type of abrasive. KW - Aluminium KW - Corrosion KW - Corrosion testing KW - Grinding PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506762 DO - https://doi.org/10.1002/maco.202011657 SN - 0947-5117 SN - 1521-4176 VL - 71 IS - 10 SP - 1667 EP - 1679 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gluth, Gregor A1 - Ebell, Gino A1 - Hlavacek, Petr A1 - Mietz, Jürgen T1 - Chloride‐induced steel corrosion in alkali‐activated fly ash mortar: Increased propensity for corrosion initiation at defects JF - Materials and Corrosion N2 - Chloride contents at the steel–mortar interface that initiate steel corrosion were determined for carbon steel in alkali‐activated fly ash mortar for three different exposure conditions: exposure to 1 M NaCl solution; leaching in deionized water and then exposure to 1 M NaCl solution; and leaching in deionized water, aging in air at 20°C and natural CO2 concentration, and then exposure to 1 M NaCl solution. For comparison, a Portland cement mortar, exposed to 1 M NaCl solution, was studied. The median values of the corrosion‐initiating chloride contents (average over the full length of the rebar) in the alkali‐activated fly ash mortar varied between 0.35 and 1.05 wt% Cl with respect to binder, consistently lower than what was obtained for the Portland cement mortar, but with no clear trend regarding the exposure conditions. For most of the alkali‐activated fly ash mortar specimens, preferential corrosion at the connection between the working electrode and the external measurement setup was observed, while preferential corrosion did not occur for the Portland cement mortar. Scanning electron microscopy and auxiliary experiments in synthetic solutions indicated that this behavior was caused by inhomogeneities at the steel–mortar interface in the alkali‐activated mortar, likely due to its peculiar rheological properties in the fresh state. KW - Alkali-activated materials KW - Steel corrosion KW - Critical chloride content KW - Steel-concrete interface PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507268 DO - https://doi.org/10.1002/maco.202011541 VL - 71 IS - 5 SP - 749 EP - 758 PB - Wiley-VCH AN - OPUS4-50726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burkert, Andreas A1 - Müller, Thoralf A1 - Lehmann, Jens A1 - Mietz, Jürgen T1 - Long-term corrosion behaviour of stainless steels in marine atmosphere JF - Materials and Corrosion N2 - Nine different stainless steel alloys were exposed for 5 years under marine environment and their corrosion behaviour was compared and assessed. The investigation of four different surface finishes for all alloys tested further enabled to consider industry-specific features of the surface finish for the material comparison. The results of the exposure tests yield conclusions regarding the influence of alloy composition, surface finish and exposure duration under marine environment. The three duplex stainless steels revealed excellent corrosion resistance even in case of crevices during the 5 years of exposure under the given exposure conditions. Also the molybdenum-alloyed ferritic steel 1.4521 showed good corrosion resistance comparable to the classical austenitic materials 1.4301 and 1.4404. KW - Corrosion KW - Free weathering KW - Marine atmosphere KW - Stainless steels PY - 2018 DO - https://doi.org/10.1002/maco.201709636 SN - 0947-5117 SN - 1521-4176 VL - 69 IS - 1 SP - 20 EP - 28 PB - Wiley-VCH Verlag GmbH & Co KGaA CY - Weinheim AN - OPUS4-43625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lehmann, Jens A1 - Burkert, Andreas A1 - Mietz, Jürgen T1 - Investigations proofing the passive layer stability of stainless steels JF - Materials and Corrosion N2 - The presented investigations have proved the principal suitability of the KorroPad method to assess the passive layer stability of stainless steels. The electrochemical mode of action could be described in detail and limitations of the applicability have been demonstrated. The influence of different surface finishes has been investigated and verified by known methods for describing corrosion resistances. As a result, the increased corrosion susceptibility of two ground surfaces has been detected, but also the corrosion resistance of further surface finishes could be confirmed. KW - Stainless steel KW - KorroPad KW - Passive layer PY - 2016 DO - https://doi.org/10.1002/maco.201408202 VL - 1 IS - 67 SP - 84 EP - 91 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-35545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -