abstract
This work aims at developing anew complex anticorrosion protection system for ZK30 magnesium alloy. This protective coating is based on an anodic oxide layer loaded with corrosion inhibitors in its pores, which is then sealed with a sol-gel hybrid polymer. The porous oxide layer is produced by spark anodizing. The sol-gel film shows good adhesion to the oxide layer as it penetrates through the pores of the anodized layer forming an additional transient oxide-sol-gel interlayer. The thickness of this complex protective coating is about 3.7-7.0 mu m. A blank oxide-sol-gel coating system or one doped with Ce3+ ions proved to be effective corrosion protection for the magnesium alloy preventing corrosion attack after exposure for a relatively long duration in an aggressive NaCl solution. The structure and the thickness of the anodized layer and the sol-gel film were characterized by scanning electron microscopy (SEM). The corrosion behaviour of the ZK30 substrates pre-treated with the complex coating was tested by electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET). and scanning ion-selective electrode techniques (SIET). (C) 2009 Elsevier Ltd. All rights reserved.
keywords
SOL-GEL COATINGS; CORROSION PROTECTION; ALUMINUM-ALLOYS; MG-ALLOY; AA2024; PERFORMANCE; CONVERSION; MECHANISM; METALS
subject category
Electrochemistry
authors
Lamaka, SV; Knornschild, G; Snihirova, DV; Taryba, MG; Zheludkevich, ML; Ferreira, MGS
our authors
Mário Guerreiro Silva Ferreira
Retired Professor
Mikhail Zheludkevich
Invited Principal Researcheracknowledgements
The financial support of FCT-Fundacao para a Ciencia e a Tecnologia, through project REDE/1509/RME/2005 and GRICES/CAPES is gratefully acknowledged.