Effect of heat treatment of magnesium alloy substrates on corrosion resistance of a hybrid organic-inorganic sol-gel film
| Autor: | Antonia Jiménez-Morales, Irene Llorente, L. Diaz, Federico R. García-Galván, Juan Carlos Galván, Sebastián Feliu |
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| Rok vydání: | 2015 |
| Předmět: |
Aqueous solution
Materials science Magnesium Scanning electron microscope General Chemical Engineering Metallurgy chemistry.chemical_element General Chemistry Sol Gel film engineering.material Dielectric spectroscopy Corrosion AZ32 chemistry Chemical engineering Coating engineering Magnesium alloy Sol-gel |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | The influence of heat treatment of magnesium alloy substrates on corrosion resistance of a sol¿gel coating has been assessed during immersion tests in 0.6 M NaCl aqueous solution. Relative differences in the chemical nature of the layers were quantified by scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX). Corrosion behaviour was evaluated by Electrochemical Impedance Spectroscopy (EIS) and hydrogen evolution measurement. Long-term immersion testing show that the sol¿gel/heat treated AZ61 substrate exhibits a superior anti-corrosion property in comparison with the sol¿gel/non-heated substrate. In contrast, no significant changes have been observed between the heated and non-heated samples in the case of the sol¿gel coated AZ31 substrates. A link was found between lower O/Si atomic ratios observed by EDX analysis on the sol¿gel coatings after the preparation process and reduced corrosion upon the coated substrates. Heat-treatment increased the protective properties of the passive film on the surface of the AZ61 substrate and hence inhibited magnesium dissolution and hydrophilic group formation during coating preparation. |
| Databáze: | OpenAIRE |
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