Active protective sealing for PEO treated magnesium alloys

• Autor(a) principal: Barbosa, Luís Filipe Santos
• Data de Publicação: 2015
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/25511
• topic: “Smart” nanocontainers; Plasma electrolytic oxidation; Inhibitors; AM50; Corrosion protection

This work pretends to test active sealants for the porosity of plasma electrolytic oxidation (PEO) coatings applied in AM50 magnesium alloy. Layered double hydroxides (LDH) were chosen as active nanocontainers and were synthesized by two different methods, so called “in situ 1” and “in situ 2” on the surface of AM50 alloy. For the in situ 1 method, the alloy substrate is used as source of cations (Mg2+) to form the LDH structure, while in situ 2 is based in co-precipitation method, with the surface acting as a nucleation point for the LDH growth. The LDH nanocontainers were intercalated with 2–Mercaptobenzothiazole. PEO was used to grow a ceramic layer on AM50 surface. In situ 2 synthesis was used to grow LDH on the surface of the ceramic PEO layer to seal the porosity of the PEO coating and add “smart” self-healing ability to this layer. The LDH and PEO coatings were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) was performed in both LDH on the surface of bare AM50 and LDH on the PEO surface in order to evaluate their corrosion behavior