Effects of inorganic ions, organic particles, blood cells, and cyclic loading on in vitro corrosion of Mg Al alloys
Effects of inorganic ions, organic particles, blood cells, and cyclic loading on in vitro corrosion of Mg Al alloys
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DOI：
10.1016/j.jma.2021.08.034
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发表时间：
2021-11
影响因子：
17.6
通讯作者：
Guanqi Liu;Jianmin Han;Ying Li;Yuzhu Guo;Xiao-dong Yu;S. Yuan;Z. Nie;C. Tan;Chuanbin Guo
中科院分区：
文献类型：
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作者：
Guanqi Liu;Jianmin Han;Ying Li;Yuzhu Guo;Xiao-dong Yu;S. Yuan;Z. Nie;C. Tan;Chuanbin Guo
近年来，镁合金作为可生物降解的植入材料引起了广泛的关注。然而，循环载荷和腐蚀环境的身体是重大的挑战，实际使用的合金，并有很少的研究，这方面的问题。在这项研究中，我们进行了一个四点弯曲疲劳试验86,400个周期（12小时）在模拟体液（SBF），血浆和全血中的AZ系列合金Mg-9Al-0.5Zn-0.27Mn-0.12Ag，以检查无机离子，有机颗粒，血细胞和循环载荷对镁合金腐蚀的影响。通过测量实验前后的Mg 2+浓度和溶液pH值，并利用三维数字显微镜、扫描电子显微镜（SEM）、能谱仪（EDS）、傅里叶变换红外光谱（FTIR）、拉曼光谱（Raman）和X射线光电子能谱（XPS）等对样品表面进行表征。浸泡在模拟体液中的镁合金试样表面形成了一层疏松的无机产物层（主要是Mg/Ca磷酸盐和碳酸盐），对镁合金的腐蚀几乎没有保护作用。对于浸泡在等离子体中的样品，有机颗粒促进了有机和更致密的产物层的形成，这保护了镁合金免受严重的腐蚀。对于浸泡在全血中的样品，血细胞影响产物层上的有机颗粒沉积，从而干扰有机致密产物层的形成，这略微加速了腐蚀过程。此外，循环加载破坏了层的完整性，并显着增加了所有的研究材料的腐蚀速率相比，不进行循环加载的样品。在循环载荷作用下，血细胞吸附在镁合金表面形成膜，保护了镁合金基体，延缓了镁合金的腐蚀。
Recently, magnesium (Mg) alloys have attracted extensive attention as biodegradable implant materials. However, cyclic loading and the corrosive environment of the body are significant challenges for the practical use of alloys, and there are few studies on this topic. In this study, we conducted a four-point bending fatigue test for 86,400 cycles (12 h) in simulated body fluid (SBF), plasma, and whole blood with an AZ series alloy Mg-9Al-0.5Zn-0.27Mn-0.12Ag, to examine the effects of inorganic ions, organic particles, blood cells, and cyclic loading on Mg alloy corrosion. The Mg2+concentration and solution pH were measured before and after experimentation, and the sample surfaces were characterized by 3D digital microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS).Our results showed that in the non-loading condition, a porous and weak inorganic product layer (mainly Mg/Ca phosphate and carbonate) formed on the surface of the Mg alloy sample immersed in SBF, which hardly had a protective effect on Mg alloy corrosion. For the samples immersed in plasma, the organic particles promoted the formation of an organic and more compact product layer, which protected the Mg alloy from severe corrosion. For the sample immersed in whole blood, the blood cells affected organic particle deposition on the product layer and thus interfered with the formation of an organic compact product layer, which slightly accelerated the corrosion process. Furthermore, cyclic loading damaged the layer integrity and significantly increased the corrosion rates of all the studied materials compared to the samples not subjected to cyclic loading. Nonetheless, under cyclic loading, blood cells adsorbed on the Mg alloy surfaces, and formed films, which protected the Mg alloy substrate and delayed Mg alloy corrosion.