Corrosion issues of powder coated AA6060 aluminium proﬁles Rameez Ud Din a,⇑ , Smári Valgarðsson b , Morten Stendahl Jellesen a , Hans Jørgen Eriksen b , Ulrik Praastrup b , Per Møller a , Rajan Ambat a a Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark b dan-color a/s, Salten Skovvej 8, Them 8653, Denmark article info Article history: Received 30 June 2014 Received in revised form 1 October 2014 Accepted 2 October 2014 Keywords: Defects Pitting corrosion Intergranular corrosion abstract In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows proﬁles has been performed. The results from this study reveals that the failure of the window proﬁles was originated from the surface defects present on the extruded AA6060 aluminium proﬁle after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the ﬂow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium proﬁles in service is explained. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction This paper summarizes the detailed analysis of quality issues found on powder coated window and door proﬁles at random locations during service, which are attributed to localise corrosion issues resulting from the micron scale defects found on extruded proﬁles. The powder coated aluminium proﬁle frames were installed in the years 2006– 2007 in Denmark and Iceland, and have been exposed to marine environmental conditions for 5–6 years due to the proximity of the installed locations to the sea. Localised corrosion, appeared as blistering of the paint, was found at random locations on the proﬁles, which was attributed to the surface features present on the extruded proﬁles prior to powder coating. Aluminium alloy used for the proﬁle was AA6060, and the studies presented in this paper elaborate the analysis of the failed part, reasons for corrosion and mechanisms. 2. Experimental and methods 2.1. Materials A series of samples (2.5 Â 2.5 cm) were prepared by cutting 1 m long AA6060 extruded and powder coated proﬁle which showed corrosion attacks. The samples were cleaned individually with ethanol in ultrasonic bath for 5 min. All samples were dried in air at room temperature for 15 min after the cleaning. http://dx.doi.org/10.1016/j.engfailanal.2014.10.001 1350-6307/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: rudin@mek.dtu.dk (R.U. Din). Engineering Failure Analysis 47 (2015) 16–24 Contents lists available at ScienceDirect Engineering Failure Analysis journal homepage: www.elsevier.com/locate/engfailanal