Sikora-Jasinska M, Chevallier P, Turgeon S, Paternoster C, Mostaed E, Vedani M, Mantovani D
Lab. for Biomaterials & Bioengineering (CRC-I), Dept. Min-Met-Materials Engineering & Research Center CHU de Québec, Laval University Pouliot Building 1745G Québec City Canada
Department of Mechanical Engineering, Politecnico di Milano Milan Italy.
RSC Adv. 2018 Mar 6;8(18):9627-9639. doi: 10.1039/c8ra00404h. eCollection 2018 Mar 5.
The major drawback of Fe-based materials for biodegradable implant applications is their slow degradation rate. Addition of second phase particles into the Fe matrix can increase the degradation rate at the beginning of the corrosion process. However, so far, there is neither quantitative data on degradation nor direct experimental evidence for long-term dissolution of Fe-based biodegradable composites. Here, a series of immersion tests at different exposure intervals (20, 50 and 100 days) to modified Hanks' solution were performed to study the degradation behavior of Fe and Fe/MgSi composites prepared by different powder metallurgy techniques. The results revealed the role of MgSi in the composition and stability of the protective films formed during the static corrosion experiments. Fe/MgSi composites showed higher degradation rates than those of pure Fe at all stages of immersion. Degradation rates at distinct exposure intervals strongly depended on the composition and stability of formed oxide, hydroxide, carbonate and phosphate protective films on the degraded surfaces. The release of Fe ions into the solution at later stages of the experiment was limited due to the barrier effect of the insoluble deposit. This fundamental study provided a basis for the processes of protective film formation in modified Hanks' solution, which enables a detailed identification of its characteristic features.
铁基材料用于可生物降解植入物时的主要缺点是其降解速率缓慢。在铁基体中添加第二相颗粒可以在腐蚀过程开始时提高降解速率。然而，到目前为止，既没有关于降解的定量数据，也没有铁基可生物降解复合材料长期溶解的直接实验证据。在此，进行了一系列在不同暴露时间间隔（20天、50天和100天）下于改性汉克斯溶液中的浸泡试验，以研究通过不同粉末冶金技术制备的铁及铁/镁硅复合材料的降解行为。结果揭示了镁硅在静态腐蚀实验过程中形成的保护膜的组成和稳定性方面所起的作用。在浸泡的各个阶段，铁/镁硅复合材料的降解速率均高于纯铁。不同暴露时间间隔下的降解速率强烈依赖于降解表面上形成的氧化物、氢氧化物、碳酸盐和磷酸盐保护膜的组成和稳定性。由于不溶性沉积物的阻挡作用，在实验后期铁离子向溶液中的释放受到限制。这项基础研究为在改性汉克斯溶液中形成保护膜的过程提供了依据，从而能够详细识别其特征。
