Revealing the early electrochemical corrosion behavior of Mg–Zn–Zr-Nd alloys in a simulated orthopedic environment

At early stages, the corrosion behavior of Mg alloys used as implant materials plays a key role to ensure a safe implantation process. Therefore, the early electrochemical corrosion behavior of Mg–2Zn-0.6Zr-xNd alloys in a simulating orthopedic environment is investigated. Results show that the T 2 and T 3 phases have lower electronic work function (2.93–3.48 eV) compared to α-Mg, therefore they are more prone to lose electrons and act as anodes during micro-galvanic corrosion. The priority dissolution of secondary phases is conducive to the uniform degradation, and the corrosion activity is reduced under the synergy of protective corrosion product film. However, the film cannot provide a stable protection in the initial stage: its destruction and reconstruction are monitored at around 12 and 20 h, while corrosion current densities are gradually reduced and eventually fluctuate at about 5 μA cm −2 . The microstructure, corrosion products, and corrosion activity evolution are interrelated and jointly affect the early electrochemical corrosion behavior of Mg–2Zn-0.6Zr-xNd alloy in a simulated orthopedic environment, among which the Mg–2Zn-0.6Zr-1.0Nd alloy exhibit better performance for the proposed application.