Permanganate-Fluorozirconate conversion coating as precursor for Flash-PEO on AZ31B magnesium alloy
The corrosion resistance of AZ31B magnesium alloy was evaluated after a two-step surface treatment consisting of a permanganate–fluorozirconate conversion layer followed by Flash-PEO in a silicate–fluoride (SiF) electrolyte. Electrochemical tests after 24 hours immersion in 0.5 wt.% NaCl demonstrate...
| Autores: | , , , |
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| Tipo de recurso: | conjunto de datos |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/125555 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/125555 |
| Access Level: | acceso abierto |
| Palabra clave: | 620 AZ31B Mg alloy Permanganate Fluorizirconate Conversion Coating Flash-PEO XPS EIS Corrosion Precursor Ingeniería química Materiales 3312 Tecnología de Materiales |
| Sumario: | The corrosion resistance of AZ31B magnesium alloy was evaluated after a two-step surface treatment consisting of a permanganate–fluorozirconate conversion layer followed by Flash-PEO in a silicate–fluoride (SiF) electrolyte. Electrochemical tests after 24 hours immersion in 0.5 wt.% NaCl demonstrated that the structured coating reduced the corrosion rate when compared to the reference Flash-PEO SiF coating ((3.4 ±1.0)x10-6 mm·yr-1 versus (1.3±0.8)x10-5 mm·yr-1). After 72 hours, this trend persisted, with impedance values at low frequency one order of magnitude higher than its counterpart without precursor layer ((1.4±1.0)x107 Ω·cm2 versus (2.6±1.0)x106 Ω·cm2). Notably, Flash-PEO coatings in both cases preserved electrochemical integrity even in the presence of pre-existing surface defects. The permanganate–fluorozirconate precursor layer promoted, after Flash-PEO processing, a distinctive “coral reef-like” morphology with reduced interconnected porosity, thereby enhancing barrier properties by limiting substrate exposure to the corrosive environment. Complementary characterization confirmed the incorporation of zirconium and manganese species, along with compounds typically derived from the Flash-PEO SiF electrolyte. |
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