摘要
Rare earth （RE） metals are widely used as the alloying implants. However, corrosion behavior of pure RE elements in biodegradable magnesium alloys as medical metals not only in physiological media but also in chlorinated saline environment is not well understood. In the present work, the RE metals Y, Nd, Gd and Dy are selected to investigate their corrosion behavior in 0.1 mol/L NaCI solution with immersion and electrochemistry techniques. As indicated, corrosion of the currently investigated RE metals is promoted in the order of Dy, Y, Gd and Nd. In terms of electrochemical response, such a sequence correlates with the increased impedance and the decreased corrosion rate （CR）. These RE metals manifest weak ability for passivation in the native surface. Then, reaction with aqueous solution easily happens through the anodic dissolution and cathodic hydrogen evolution. The corrosion products, RE（OH）3, adhered on the surface of RE metals, do not have an appreciable power to resist the reaction proceeding with corrosive chloride ions. In contrast to pure Mg, the RE metals, including Y, Nd, Gd and Dy, exhibit significantly fragile corrosion resistance in saline media. Therefore, with the curr correlation of corrosion resistance between RE-contain ent findings, it is impossible to reveal a well-defined ng Mg alloy and RE metal itself
Rare earth （RE） metals are widely used as the alloying implants. However, corrosion behavior of pure RE elements in biodegradable magnesium alloys as medical metals not only in physiological media but also in chlorinated saline environment is not well understood. In the present work, the RE metals Y, Nd, Gd and Dy are selected to investigate their corrosion behavior in 0.1 mol/L NaCI solution with immersion and electrochemistry techniques. As indicated, corrosion of the currently investigated RE metals is promoted in the order of Dy, Y, Gd and Nd. In terms of electrochemical response, such a sequence correlates with the increased impedance and the decreased corrosion rate （CR）. These RE metals manifest weak ability for passivation in the native surface. Then, reaction with aqueous solution easily happens through the anodic dissolution and cathodic hydrogen evolution. The corrosion products, RE（OH）3, adhered on the surface of RE metals, do not have an appreciable power to resist the reaction proceeding with corrosive chloride ions. In contrast to pure Mg, the RE metals, including Y, Nd, Gd and Dy, exhibit significantly fragile corrosion resistance in saline media. Therefore, with the curr correlation of corrosion resistance between RE-contain ent findings, it is impossible to reveal a well-defined ng Mg alloy and RE metal itself
基金
supported by the National Natural Science Foundation of China under grant No. 51001099
