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Nanoparticle-based impregnation of chromate-free anodizing layers for corrosion protection and adhesive bonding

 
: Anthes, Adrian; Weidmann, Stefanie; Fürbeth, Wolfram; Kremmer, Kerstin; Schneider, Michael

:

Surface and coatings technology 348 (2018), pp.121-129
ISSN: 0257-8972
Bundesministerium für Wirtschaft und Technologie BMWi

Optimierung der Modifizierung von Anodisierschichten auf Aluminiumwerkstoffen durch chemische Nanotechnologie und industrielle Anpassung des Verfahrens
English
Journal Article
Fraunhofer IKTS ()
anodizing; AA 1050; SiO2-nanoparticle; MPAA; adhesive bonding; chemical nanotechnology

Abstract
The present work suggests a new approach of chromate-free surface pretreatment of aluminum alloy AA 1050 by using a modified phosphoric acid anodizing process, followed by an impregnation with a commercial SiO2-nanoparticle dispersion (Levasil® 300/30%) by dip-coating technique. The nanoparticles constitute an additional barrier layer against corrosion without closing the pores completely. The open porous oxide layer is a suitable promoter of adhesive bonding. The influence of withdrawing speed, the dipping time, solid content, temperature and pH-value in respect to the filling height in the pores of the anodized oxide layer were investigated. Surface morphology of the impregnated anodic oxide layers as well as their cross-section microstructure were investigated by scanning electron microscopy (SEM). Corrosion properties were investigated by electrochemical impedance spectroscopy (EIS) and adhesion was evaluated by single lap shear tests.

: http://publica.fraunhofer.de/documents/N-503889.html