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An automated method for corrosion testing of coating systems on magnesium alloys

Ein automatisiertes Verfahren zur Korrosionsprüfung von Beschichtungssystemen auf Magnesiumlegierungen
Carsten Blawert, Wolfgang Dietzel and Volker Heitmann
From the journal Materials Testing

Abstract

The present work introduces an automated corrosion test for coating systems on magnesium alloys, which is based on the titration method introduced by General Motors [1], in which the dissolution rate of magnesium is determined from the amount of HCl added to a sodium chloride solution required to maintain a constant pH value. It is demonstrated that this technique allows a screening of various types of coatings on magnesium alloys yielding much more information than a standard salt spray test or a simple standard immersion test. The main advantage lies in the continuous measurement of the corrosion rate without disturbing the corrosion system and without the need for cleaning the specimens from corrosion products in order to measure weight changes.

Kurzfassung

Der vorliegende Beitrag stellt ein automatisiertes Prüfverfahren zur Korrosionsprüfung von Beschichtungssystemen auf Magnesiumlegierungen vor. Es beruht auf dem von General Motors eingeführten Titrationsverfahren, in dem die Auflösungsrate von Magnesium anhand des Anteiles von Salzsäure bestimmt wird, die einer Natriumchloridlösung zugegeben werden muss, um den pH-Wert konstant zu halten. Es wird gezeigt, dass diese Methode eine Prüfung von verschiedenen Beschichtungstypen auf Magnesiumlegierungen erlaubt und viel mehr Informationen zur Verfügung stellt als ein standardisierter Salzsprühtest oder Eintauchversuch. Der Hauptvorteil des Verfahrens liegt in der kontinuierlichen Messung der Abtragsrate, ohne das Korrosionssystem an sich zu stören und ohne die sonst notwendige Reinigung der Probe zur Messung von Gewichtsveränderungen vornehmen zu müssen.


Dr.-Ing. Carsten Blawert, born 1966, has studied Materials Science at the Technical University of Clausthal, where he also finished his PhD in the field of surface modification of steels. After several years of working experience at the TU Clausthal and the Zentrum für Funktionswerkstoffe gGmbH, he joined GKSS-Forschungszentrum Geesthacht GmbH in 2002. He works for the corrosion section of the Center for Magnesium Technology at the Institute for Materials Research. His main interest is in the corrosion and corrosion protection of magnesium alloys.

Wolfgang Dietzel, born 1946, holds an M. Sc. in solid state physics from the Technical University Clausthal and a PhD. in Engineering Sciences from the Technical University Hamburg-Harburg. After working as a patent engineer in ordnance and aerospace industry companies, he joined in 1986 the GKSS-Forschungszentrum Geesthacht GmbH to establish a laboratory for stress corrosion cracking testing. Since 1995, he is head of the Corrosion Section of the Institute for Materials Research of the GKSS Research Center. Focus of his work is on the fracture mechanics approach to environment-assisted cracking and, more recently, on the corrosion and corrosion protection of magnesium alloys. Wolfgang Dietzel is Chairman of the Technical Committee 10, Environmentally Assisted Cracking, of the European Structural Integrity Society, ESIS, and member of ISO TC 156, Corrosion of Metals and Alloys.

Volker Heitmann, born 1964, has studied mechanical engineering at the FH Hamburg. After getting the certificate of the european welding engineer he worked as an assessor. He joined GKSS in 1999. First he worked in the area of fracture mechanics, and since 2003 in the corrosion section of the Center for Magnesium Technology.


Literatur

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8 Song, G., Atrens, A.: Understanding magnesium corrosion, Adv. Eng. Mater., 5 (2003), No. 12, pp. 837858 The authors Dr.-Ing. Carsten Blawert, born 1966, has studied Materials Science at the Technical University of Clausthal, where he also finished his PhD in the field of surface modification of steels. After several years of working experience at the TU Clausthal and the Zentrum für Funktionswerkstoffe gGmbH, he joined GKSS-Forschungszentrum Geesthacht GmbH in 2002. He works for the corrosion section of the Center for Magnesium Technology at the Institute for Materials Research. His main interest is in the corrosion and corrosion protection of magnesium alloys. Wolfgang Dietzel, born 1946, holds an M. Sc. in solid state physics from the Technical University Clausthal and a PhD. in Engineering Sciences from the Technical University Hamburg-Harburg. After working as a patent engineer in ordnance and aerospace industry companies, he joined in 1986 the GKSS-Forschungszentrum Geesthacht GmbH to establish a laboratory for stress corrosion cracking testing. Since 1995, he is head of the Corrosion Section of the Institute for Materials Research of the GKSS Research Center. Focus of his work is on the fracture mechanics approach to environment-assisted cracking and, more recently, on the corrosion and corrosion protection of magnesium alloys. Wolfgang Dietzel is Chairman of the Technical Committee 10, Environmentally Assisted Cracking, of the European Structural Integrity Society, ESIS, and member of ISO TC 156, Corrosion of Metals and Alloys. Volker Heitmann, born 1964, has studied mechanical engineering at the FH Hamburg. After getting the certificate of the european welding engineer he worked as an assessor. He joined GKSS in 1999. First he worked in the area of fracture mechanics, and since 2003 in the corrosion section of the Center for Magnesium Technology.Search in Google Scholar

Published Online: 2013-05-26
Published in Print: 2005-06-01

© 2005, Carl Hanser Verlag, München

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