Micro-arc oxidation (MAO) enhances the corrosion resistance of magnesium alloys, but the resulting porous property of the MAO layer facilitates the ingress of corrosive media. This study presents a synergistic sealing treatment using cerium nitrate and stearic acid under ambient conditions to improve MAO-treated magnesium alloy's corrosion resistance, durability, and hydrophobicity. The impact of varying immersion times in cerium nitrate solution on sealing morphologies was also assessed. Results indicate that the specimen with a two-hour immersion shows the fewest micrometer-sized pores, smallest pore sizes, and minimal microcracks. Further sealing treatment with stearic acid, the charge transfer resistance of composite coating ( R ct ) was 186 times greater than the unsealed MAO coating, reaching 24.6 MΩ cm 2 . Additionally, the corrosion current density j corr after 15 days of immersion was three orders of magnitude lower than that of the unsealed coating, down to 1.88 nA cm −2 . These findings introduce a novel strategy for sealing micro-arc oxidized magnesium alloys, highlighting a promising approach to enhance their corrosion resistance, durability, and hydrophobicity, expanding their potential applications.
Ye Tian,Haijun Zhang,Xiuyong Chen,André McDonald,Shuangjie Wu,Tonghu Xiao,Hua Li
This study aims to further improve the cavitation-corrosion performances of high-velocity oxygen-fuel (HVOF) sprayed WC-10Co4Cr coatings by post-sealing treatment with epoxy resin using a vacuum impregnation method. Compared with the as-sprayed coatings with a porosity of 2.52%, the sealed WC-10Co4Cr coatings with a much lower porosity of 0.78% were successfully fabricated. The sealed coatings showed significantly enhanced corrosion and cavitation resistance tested in artificial seawater compared to those of the as-sprayed coatings. Further cavitation-corrosion testing under cavitation and quiescence conditions showed that the corrosion rate of both the as-sprayed coating and sealed coating was reduced under cavitation condition. Furthermore, a mechanism was suggested to illustrate the effect of cavitation on corrosion behavior of the coatings. The sealing treated WC-10Co4Cr coatings show encouraging promises as cavitation-corrosion resistance layers for marine structures.
危险品化学品经营许可证（带存储）