Liu Wei, Yan Zhijie, Ma Xiaolu, Geng Tie, Wu Haihong, Li Zhongyue
School of Mechanical & Electrical Engineering, Henan University of Technology, Zhengzhou 450001, China.
School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China.
Materials (Basel). 2018 Mar 7;11(3):396. doi: 10.3390/ma11030396.
Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal-organic framework/MgF₂ (Mg-MOF-74/MgF₂) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF₂ composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF₂ composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF₂ anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface.
镁合金的表面改性在骨修复领域的应用前景广阔。在本研究中，通过氢氟酸预处理和原位水热合成法在AZ31B镁合金表面制备了一种新型金属有机框架/MgF₂（Mg-MOF-74/MgF₂）复合涂层。复合涂层的表面形貌致密且均匀，Mg-MOF-74具有良好的结晶度。通过Tafel极化试验和在37℃模拟体液中的浸泡试验研究了该复合涂层的耐腐蚀性。结果发现，Mg-MOF-74/MgF₂复合涂层显著减缓了镁合金的腐蚀速率。此外，Mg-MOF-74/MgF₂复合涂层表现出超亲水性，水接触角接近0°。总之，在MgF₂防腐涂层的基础上，引入Mg-MOF-74进一步改善了镁合金的生物学性能。最后，我们认为复合涂层的亲水性主要归因于大量的羟基、Mg-MOF-74的高比表面积以及Mg-MOF-74颗粒产生的粗糙涂层。因此，Mg-MOF-74在增强镁合金表面亲水性方面具有很大优势。
