Fault-tolerant hybrid epoxy-silane coating for corrosion protection of magnesium alloy AZ31
authors Lamaka, SV; Xue, HS; Meis, NNAH; Esteves, ACC; Ferreira, MGS
nationality International
journal PROGRESS IN ORGANIC COATINGS
author keywords Magnesium alloy; AZ31; Epoxy-silane coating; Corrosion; EIS; Inhibitor
keywords SOL-GEL COATINGS; ORGANIC COATINGS; IONIC CURRENTS; SILICA HYBRIDS; PH
abstract In this work, a hybrid epoxy-silane coating was developed for corrosion protection of magnesium alloy AZ31. The average thickness of the film produced by dip-coating procedure was 14 mu m. The adhesion strength of the epoxy-silane coating to the Mg substrate was evaluated by pull-off tests and was found to be higher than 16 MPa both in dry and wet conditions. The hybrid epoxy-silane coating showed high corrosion resistance both when intact and when punched through by a needle. The low frequency impedance of intact coating was higher than 1 G Omega cm(2) after one month of immersion in 3.5% NaCl solution. Both, artificially induced defects and corrosion sites that appeared on the metal surface did not propagate. Their passivation behavior, that we call fault-tolerance, was observed by EIS, SVET-SIET and SEM-EDS. It was ascribed to the good adhesion, high coating integrity and corrosion inhibiting effect provided by diethylenetriamine used as epoxy hardener. (C) 2014 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE SA
issn 0300-9440
year published 2015
volume 80
beginning page 98
ending page 105
digital object identifier (doi) 10.1016/j.porgcoat.2014.11.024
web of science category Chemistry, Applied; Materials Science, Coatings & Films
subject category Chemistry; Materials Science
unique article identifier WOS:000349511900013

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