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

Abstract

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

Electrochemical Behavior of AZ31 Mg Alloy in Neutral Aqueous Solutions Containing Various Anions

“…OHions can lead to the passivation of Mg alloys by the formation of protective surface films of Mg(OH) 2 or complex hydroxide compounds. This layer acts as a barrier against diffusion of aggressive ions, thereby protecting the Mg alloy surface from corrosion to some extent in corrosive environment [28][29][30].…”

Preparation and properties of Mg-Nd binary alloy MAO/SiO2@α-Fe2O3 organic composite coating

“…In order to improve the wave absorption and corrosion resistance of magnesium alloys, Ni, barium ferrite (BF) and carbonyl iron (CI) powders were coated on the magnesium matrix in the form of microwave absorbing coatings to improve the wave absorption properties 20,21 . Microarc oxidation coating (MAO) [22][23][24][25] sol-gel coating 26,27 chemical conversion coating 28,29 , hydrothermal treatment 30,31 and other surface treatment methods can improve the corrosion resistance to a certain extent. The coating prepared by the micro-arc oxidation process has good hardness, adhesion and corrosion resistance, and the process is simple, clean and environmentally friendly.…”

A Cost-Effective Method for Preparing Robust and Conductive Superhydrophobic Coatings Based on Asphalt

“…However, most steel is prone to be corroded, which results in massive economic losses. Many methods have been developed to prohibit the corrosion [ 4 – 7 ]. Particularly, superhydrophobic materials, which can be fabricated by the combination of micro/nanostructure and low surface energy, are attracting more and more attention because the water droplets can maintain nearly spherical shape on them and roll off easily [ 8 – 11 ].…”