Fault-tolerant hybrid epoxy-silane coating for corrosion protection of magnesium alloy AZ31

作者：Lamaka S V^*; Xue H S; Meis N N A H; Esteves A C C; Ferreira M G S

来源：Progress in Organic Coatings, 2015, 80: 98-105.

DOI：10.1016/j.porgcoat.2014.11.024

• Magnesium alloy
• AZ31
• Epoxy-silane coating
• Corrosion
• EIS
• Inhibitor

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.

• 出版日期2015-3