Influence of Cu2+ Ions on the Corrosion Resistance of AZ31 Magnesium Alloy with Microarc Oxidation

Abstract

The objectives of this study were to reduce the corrosion rate and increase the cytocompatibility of AZ31 Mg alloy. Two coatings were considered. One coating contained MgO (MAO/AZ31). The other coating contained Cu2+ (Cu/MAO/AZ31), and it was produced on the AZ31 Mg alloy via microarc oxidation (MAO). Coating characterization was conducted using a set of methods, including scanning electron microscopy, energy-dispersive spectrometry, X-ray photoelectron spectroscopy, and X-ray diffraction. Corrosion properties were investigated through an electrochemical test, and a H2 evolution measurement. The AZ31 Mg alloy with the Cu2+-containing coating showed an improved and more stable corrosion resistance compared with the MgO-containing coating and AZ31 Mg alloy specimen. Cell morphology observation and cytotoxicity test via Cell Counting Kit-8 assay showed that the Cu2+-containing coating enhanced the proliferation of L-929 cells and did not induce a toxic effect, thus resulting in excellent cytocompatibility and biological activity. In summary, adding Cu ions to MAO coating improved the corrosion resistance and cytocompatibility of the coating.

Review of the Effect of Surface Coating Modification on Magnesium Alloy Biocompatibility

“…Li et al [43] showed that by adding rare earth elements, the corrosion resistance is improved by reducing the active area of the substrate surface. With the deepening of research, in recent years, strontium [44], gallic acid [45], and copper [46], which can enhance bone formation and antibacterial effects, have been added to electrolyte solutions.…”

Effect of Cu2+ on Corrosion Behavior of A106B Carbon Steel and 304L Stainless Steels in Seawater

“…Presently, the corrosion of steels in seawater had been widely investigated all over the world [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], and the influence of Cu 2+ on material corrosion is mainly focused on different materials in nonseawater environment, such as steel [21][22][23][24][25][26][27][28][29][30], aluminum alloy [31,32], 690 alloy [33], and copper alloy [34]. However, the works focused on the corrosion behavior of steels in seawater containing Cu 2+ and the influence of the Cu 2+ and copper oxides on the corrosion of the equipment in the secondary circuit system were little reported [35].…”