Improved Corrosion Resistance of Magnesium Alloy in SimulatedConcrete Pore Solution by Hydrothermal Treatment

Magnesium alloys are considered for building materials in this study due to their natural immunity to corrosion in alkaline concretepore solution. But, chloride ions attack often hinders the application of most metals. Therefore, it is necessary to conduct apreliminary corrosion evaluation and attempt tofind an effective way to resist the attack of chloride ions in concrete poresolution. In our study, hydrothermal treatment is carried out to modify Mg-9.3 wt. % Al alloy. After the treatment in NaOHsolution for 10 h, scanning electron microscopy (SEM) reveals that a layer of dense coating with a thickness of about 5μmisformed on Mg alloy. Energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-rayDiffraction (XRD) are combined to analyze the coating, and it is thereby confirmed that the coating is mainly composed ofMg(OH)2. As expected, both immersion test and electrochemical corrosion test show that the coated magnesium alloy has abetter corrosion resistance than the uncoated one in simulated concrete pore solution with and without chloride ions. Insummary, it indicates that hydrothermal treatment is a feasible method to improve the corrosion resistance of Mg alloys usedfor building engineering from the perspective of corrosion science.