Self-healing plasma electrolytic oxidation coatings doped with benzotriazole loaded halloysite nanotubes on AM50 magnesium alloy

• DOI: 10.1016/j.corsci.2016.06.016
• Publication Date: 2016-06-16T06:20:23Z
• Authors: M. Sun; A. Yerokhin; M.Ya. Bychkova; D.V. Shtansky; E.A. Levashov; A. Matthews
• Keywords: Halloysite; Benzotriazole; Plasma electrolytic oxidation

Abstract Halloysite nanotubes (HNT) and benzotriazole (BTA) loaded HNT were added to a silicate-based electrolyte to produce PEO coatings on AM50 alloy. The coatings were characterised by SEM, EDX and XRD methods. Corrosion behaviour in 3.5 wt.% NaCl was studied by EIS and PDP scans. The HNT increased coating scratch resistance greater than BTA-HNT, although the latter enhanced corrosion resistance due to a self-healing effect. This was triggered by a dense Mg(OH)2 film being formed on corrosion sites following partial coating degradation, preventing pitting corrosion. The single-step process for producing self-healing PEO coatings has good potential in corrosion protection of Mg.