TY - CONF A1 - Bender, S. A1 - Heyn, Andreas T1 - Evaluation and Screening of the pre-treatment states of Mg-alloys using Electrochemical Noise T2 - EUROCORR 2009 - Corrosion from the nanoscale to the plant N2 - A successful application of magnesium alloys as light structural materials and for special applications, such as in the medical sector, depends significantly on their corrosion properties. Since the use of well-chosen surface coating systems can optimize these properties, many efforts are going in this direction. In general, any coating process must be seen in a close connection to the pre-treatment of the alloy surface, particularly for magnesium alloys. The pre-treatment is required to prepare the optimal surface for a coating system, in which adhesion and dissolution behaviour are the central properties. In the case of magnesium alloys this means a well-controlled removal of the casting or rolling skin, which would be prone to corrosion and poor adhesion. Additionally, in most cases the surface morphology should be smooth. An investigation of different pickling solutions and pickling parameters showed a wide range of effectiveness (i.e., the resulting mass loss and surface morphology). Another important and often underestimated fact is the comparatively strong tendency of magnesium to react with the atmosphere. For that reason, after a completed pickling and cleaning treatment the condition of the surrounding atmosphere and the time prior to coating of the surface should be taken into account because of the formation of different reaction layers. These layers have an effect on adhesion and the corrosion properties of the coating system as a whole. For a documentation of the influence of different atmospheres and the timedependence of the surface activity the measurement of the electrochemical noise is the preferred technique. This is because it shows instantaneously the actual activity, even in the absence of external excitation. The influence of different pre-treatments as well as exposure conditions and duration was investigated using electrochemical noise measurements as a screening method. As a result the pretreatment which is an important part of the coating process could be considerably improved. T2 - EUROCORR 2009 CY - Nice, France DA - 2009-09-06 KW - Magnesium KW - Pre-treatment KW - Pickling KW - Electrochemical noise PY - 2009 IS - Paper 8080 SP - 1 EP - 8 AN - OPUS4-20064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -