ABSTRACT

Magnesium alloys have received increasing consideration as biodegradable implants owing to their high specific strength, excellent biocompatibility and non-toxicity but their biomedical applications are limited due to low corrosion resistance which can be improved by surface modification and alloying with suitable elements. Various surface modifications of Mg alloys by deposition of different coatings are used to prevent untimely dissolution. This study presents the corrosion behaviour of a thin ZnO coating deposited on a Mg–Zn–Zr alloy by electrophoretic deposition in the Ringer’s solution at 37°C. It was found that the ZnO coating is compact, homogeneous and significantly enhanced its corrosion resistance according to electrochemical test. The polarisation test showed a two orders of magnitude lower current density than that of the bare alloy, while EIS study found a two orders of magnitude greater ZnO coating impedance increasing in bioactivity. The bare specimens showed the development of cracks on the surface whereas the ZnO coated alloy showed no signs of pitting.

摘要

镁合金由于其高比强度、优异的生物相容性和无毒性而越来越多地被认为是可生物降解的植入物，但由于耐腐蚀性低，其生物医学应用受到限制，而耐腐蚀性可以通过表面改性和与适当元素合金化来改善。通过沉积不同涂层对镁合金进行各种表面改性，以防止过早溶解。本研究展示了在 37°C 的林格氏溶液中通过电泳沉积在 Mg-Zn-Zr 合金上沉积的薄 ZnO 涂层的腐蚀行为。电化学测试发现ZnO镀层致密、均匀，耐腐蚀性能显着增强。极化测试显示电流密度比裸合金低两个数量级，而 EIS 研究发现，ZnO 涂层的生物活性阻抗增加了两个数量级。裸露的样品表面出现裂纹，而氧化锌涂层合金没有出现点蚀迹象。