PEO coating on Mg-Ag alloy: The incorporation and release of Ag species
Xinxin Zhang, Yupeng Zhang, You Lv, Zehua Dong, Lei Yang, Erlin Zhang, Teruo Hashimoto, Xiaorong Zhou
Abstract
In the present study, the distribution of Ag in the coating formed on Mg-Ag alloy by plasma electrolytic oxidation (PEO) and its ionic release kinetics when exposed to a 0.9 wt.% NaCl solution at 37 °C have been investigated. Both metallic Ag and Ag oxide particles with ∼5 to ∼40 nm in diameters were observed in the PEO coating. Further, an Ag-enriched layer of ∼20 nm in thickness at the substrate/coating interface was also observed. The PEO coating on the Mg-Ag alloy not only increases its corrosion resistance with the corrosion current density decreasing by up to 3 orders of magnitude from 8.04 × 10−3 to 4.03 × 10−6 A/cm2, but also controls the release of Ag+ to the level that is sufficient for anti-infective efficacy without causing cytotoxicity to mammal cells.