Roles of the micro‐arc oxidation coating on the corrosion resistance and mechanical properties of extruded Mg–2Zn–0.5Zr–1.5Dy (mass%) alloy. Issue 3 (18th October 2021)

• Record Type: Journal Article
• Authors: Li, Huan; Wen, Jiuba; Jin, Jie; Liu, Ya; He, Junguang
• Is Part Of: Materials and corrosion. Volume 73:Issue 3(2022)
• Page Start: 414
• Page End: 426
• Publication Date: 2021-10-18
• Subjects: biodegradable magnesium alloy -- corrosion resistance -- mechanical properties -- micro‐arc oxidation; Materials -- Periodicals; Metals -- Periodicals; Corrosion and anti-corrosives -- Periodicals; 620.1122305
• DOI: 10.1002/maco.202112762
• Languages: English
• ISSNs: 0947-5117

Abstract

Abstract: Aiming to enhance the biodegradable magnesium alloys' poor mechanical properties and corrosion resistance in aggressive chloride mediums, micro‐arc oxidation coatings with oxidation times range from 3 to 15 min were prepared on the surface of extruded Mg–2Zn–0.5Zr–1.5Dy (mass%) alloy. Assessments were carried out using electrochemical experiments, hydrogen evolution experiments, and tensile tests, respectively. The results show that the micro‐arc oxidation coating is porous and mainly consists of the MgO phase. When the oxidation time increases from 3 to 15 min, the thickness and the pore size of the coating increase, while the coating's porosity decreases. The coating with the oxidation time of 15 min can effectively prevent the formation of pitting holes on the surface of the alloy, which remarkably reduces the decay rate of ultimate tensile strength, yield strength, and elongation of the alloy after immersion in simulated body fluid for 0–28 days, and keep the alloy with higher and more stable corrosion resistance. This increases the application possibility of extruded Mg–2Zn–0.5Zr–1.5Dy alloy as a biodegradable material. Abstract : Micro‐arc oxidation (MAO) coating can effectively improve the corrosion resistance and reduce the decay rate of the mechanical properties of magnesium alloy, but the protective effect of MAO coating on the alloy is temporary. The destruction of MAO coating promotes the formation of pitting holes and significantly deteriorates the mechanical properties of the alloy.