TY - JOUR A1 - Heyn, Andreas A1 - Schilling, K. A1 - Boese, E. A1 - Spieler, S. A1 - Altendorf, S. A1 - Burkert, Andreas A1 - Schultze, S. T1 - Lochkorrosionsverhalten von Auftragschweißungen - Schweißlagen- und Oberflächeneffekte N2 - Zur vergleichenden Einschätzung der Lochkorrosionsbeständigkeit von verschiedenen, mehrlagigen MAGp-auftraggeschweißten Nickelbasis-Schweißgütern auf einem Superduplexstahl wurden kritische Lochkorrosionstemperaturen (critical pitting temperature, CPT) nach ASTM G 48 C ermittelt. Es zeigte sich eine unerwartet niedrige Beständigkeit der Auftragschweißungen, als dessen Ursache ein ungünstiger Oberflächenzustand angenommen wurde. Da die CPT-Bestimmung nach ASTM keine Aussage über den Korrosionsverlauf gestattet und Untersuchungen über einen weiten Temperaturbereich damit sehr aufwendig sind, wurde eine neue Prüfmethode angewandt. Diese ermittelt die CPT mit Hilfe des elektrochemischen Stromrauschens zwischen zwei gleichartigen Proben in der nach ASTM G 48 C geforderten Prüflösung bei kontinuierlicher Temperaturerhöhung. Dadurch war es möglich, den Einfluss des Oberflächenzustandes auf das Lochkorrosionsverhalten der untersuchten Proben schnell nachzuweisen und geeignete Maßnahmen zu ergreifen. Der beim MAGp-Schweißen entstehende oxidische Oberflächenbelag beeinflusst die Lochkorrosionsbeständigkeit negativ. Nach der mechanischen Beseitigung der Beläge durch Strahlen oder Schleifen weisen die Proben eine wesentlich höhere Lochkorrosionsbeständigkeit auf, und es konnte die Abhängigkeit von der Anzahl der Schweißlagen ermittelt werden. Translated Abstract Pitting corrosion behaviour of built-up welds - Effects of welding layers and tarnish - The pitting corrosion resistance of nickel based deposition welds on a superduplex steel made by active-gas metal pulsed-arc welding was studied. Therefore the determination of the CPT (Critical Pitting Temperature) should be carried out corresponding to ASTM G 48 C. However an unexpectedly low resistance of the built-up welds also at multilayer order was noticed. After visual assessment of the examined specimens a significant effect of the surface condition was assumed. Because the CPT determination according to ASTM does not allow any statement about the corrosion process, this method was not suitable to characterize the corrosion system. For this reason a new method was applied to clarify the causes of the low corrosion resistance. This method determines the CPT with the help of the electrochemical current noise under the same conditions demanded in ASTM G 48 C. The temperature is increased continuously and the characteristic parameters of the system are recorded and evaluated objectively within short time. So it was possible to see the influence of the surface condition on the pitting corrosion behaviour of the examined specimens. The required parameters to the post-processing of the deposition welds were determined. The comparison of the results show that the surface tarnish formed after the shielded arc welding process influences the pitting corrosion resistance negatively. After its elimination the CPT could be determined in dependence of the welding layers. PY - 2003 DO - https://doi.org/10.1002/maco.200303758 SN - 0947-5117 SN - 1521-4176 VL - 54 IS - 12 SP - 947 EP - 952 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2774 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturgeon, R. E. A1 - Wahlen, R. A1 - Brandsch, T. A1 - Fairman, B. A1 - Wolf-Briche, C. A1 - Alonso, J. I. G. A1 - González, P. R. A1 - Encinar, J. R. A1 - Sanz-Medel, A. A1 - Inagaki, K. A1 - Takatsu, A. A1 - Lalere, B. A1 - Monperrus, M. A1 - Zuloaga, O. A1 - Krupp, E. A1 - Amouroux, D. A1 - Donard, O. F. X. A1 - Schimmel, H. A1 - Sejeroe-Olsen, B. A1 - Konieczka, P. A1 - Schultze, P. A1 - Taylor, P. A1 - Hearn, R. A1 - Mackay, L. A1 - Myors, R. A1 - Win, Tin A1 - Liebich, Almuth A1 - Philipp, Rosemarie A1 - Yang, L. A1 - Willie, S. T1 - Determination of tributyltin in marine sediment: Comité Consultatif pour la Quantité de Matière (CCQM) pilot study P-18 international intercomparison N2 - The capabilities of National Metrology Institutes (NMIs—those which are members of the Comité Consultatif pour la Quantité de Matière (CCQM)of the CIPM) and selected outside "expert" laboratories to quantitate (C4H9)3Sn+ (TBT) in a prepared marine sediment were assessed. This exercise was sanctioned by the 7th CCQM meeting, April 4–6, 2001, as an activity of the Inorganic Analysis Working Group and was jointly piloted by the Institute for National Measurement Standards of the National Research Council of Canada (NRC) and the Laboratory of the Government Chemist (LGC), UK. A total of 11 laboratories submitted results (7 NMIs, and 4 external labs). Two external laboratories utilized a standard calibration approach based on a natural abundance TBT standard, whereas all NMIs relied upon isotope dilution mass spectrometry for quantitation. For this purpose, a species specific 117Sn-enriched TBT standard was supplied by the LGC. No sample preparation methodology was prescribed by the piloting laboratories and, by consequence, a variety of approaches was adopted by the participants, including mechanical shaking, sonication, accelerated solvent extraction, microwave assisted extraction and heating in combination with Grignard derivatization, ethylation and direct sampling. Detection techniques included ICP–MS (with GC and HPLC sample introduction), GC–MS, GC–AED and GC–FPD. Recovery of TBT from a control standard (NRCC CRM PACS-2 marine sediment) averaged 93.5±2.4% (n=14). Results for the pilot material averaged 0.680±0.015 µmol kg–1 (n=14; 80.7±1.8 µg kg–1) with a median value of 0.676 µmol kg–1. Overall, performance was substantially better than state-of-the-art expectations and the satisfactory agreement amongst participants permitted scheduling of a follow-up Key comparison for TBT (K-28), a Pilot intercomparison for DBT (P-43), and certification of the test sediment for TBT content and its release as a new Certified Reference Material (HIPA-1) with a TBT content of 0.679±0.089 µmol kg–1 (expanded uncertainty, k=2, as Sn) (80.5±10.6 µg kg–1). Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00216-003-2016-9. KW - Tributyltin KW - Marine sediment KW - International intercomparison PY - 2003 DO - https://doi.org/10.1007/s00216-003-2016-9 SN - 1618-2642 SN - 1618-2650 VL - 376 IS - 6 SP - 780 EP - 787 PB - Springer CY - Berlin AN - OPUS4-10905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -