3D honeycomb nanostructure-encapsulated magnesium alloys with superior corrosion resistance and mechanical properties
3D honeycomb nanostructure-encapsulated magnesium alloys with superior corrosion resistance and mechanical properties
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具有优异耐腐蚀性和机械性能的3D蜂窝纳米结构封装镁合金
DOI：
10.1016/j.compositesb.2019.01.031
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发表时间：
2019-04-01
影响因子：
13.1
通讯作者：
Gao, Chengde
中科院分区：
文献类型：
--
作者：
Shuai, Cijun;Wang, Bing;Gao, Chengde
镁（Mg）合金是一种很有前途的生物可降解金属，但由于其降解速度太快而受到限制。采用选择性激光熔化技术制备了以氧化石墨烯（GO）为第二相的蜂窝状纳米结构包裹镁合金的三维蜂窝状纳米结构。结果表明，随着GO含量的增加，GO沿着晶界分布，并逐渐包裹α-Mg晶粒。值得注意的是，在一定的GO含量（在本研究中为1.0重量%）下，形成了蜂窝状纳米结构，其中α-Mg晶粒包封在蜂窝单元中。结果表明：GO的加入降低了α-Mg晶粒间的相互连接，促进了α-Mg晶粒的形核，细化了α-Mg晶粒; GO的抗渗透性使蜂窝状结构起到了阻挡腐蚀的作用; GO的加入降低了α-Mg晶粒间的相互连接，促进了α-Mg晶粒的形核;（III）氧化石墨强化了腐蚀层，阻止了腐蚀层从镁基体上脱落;（IV）氧化石墨上的含氧基团促进了类骨磷灰石的沉积，进一步阻碍了腐蚀介质的侵入。这些研究结果表明，蜂窝纳米结构封装的镁合金对腐蚀的多重防御作用和它们在生物医学应用中的巨大潜力。
Magnesium (Mg) alloys are promising biodegradable metals for biomedical applications but limited by their too fast degradation rates. In this study, selective laser melting was used to fabricate three-dimensional honeycomb nanostructure-encapsulated Mg alloys, in which the honeycomb nanostructure was constructed by graphene oxide (GO) as a second phase and the grains of Mg alloys were encapsulated in the honeycomb unit. Results showed that GO distributed along the grain boundaries and gradually wrapped alpha-Mg grains as GO content increasing. It was worth noting that a honeycomb nanostructure was formed with alpha-Mg grains encapsulated in the honeycomb unit at a certain GO content (1.0 wt% in this study). As a result, the corrosion resistance and mechanical properties were both improved, which might be ascribed to the following mechanisms: (I) alpha-Mg grains were refined due to the reduced connection and promoted nucleation by GO; (II) Benefiting from the outstanding anti-permeability of GO, the honeycomb nanostructure acted as a tight barrier to restrain the propagation of corrosion; (III) GO reinforced the corrosion layer to prevent it falling off the Mg matrix; (IV) The oxygen-containing groups on GO facilitated the deposition of bone-like apatite and further hindered the invasion of corrosive medium. These findings demonstrated the multiple defensive roles against corrosion in the honeycomb nanostructure-encapsulated Mg alloys and their great potential in biomedical applications.