纯镁在不同腐蚀体系中的降解行为研究

目的: 观察纯镁在不同体系中的降解行为,研究其在不同介质中不同的降解机制。 方法: 利用模拟体液(SBF)和细胞培养基(DMEM)分别作为纯镁的腐蚀介质,参照ASTM-G31-72标准选择相应体积的溶液进行浸泡,测量1 d、2 d、4 d、8 d和16 d各体系中钙镁离子浓度、pH改变,并通过扫描电镜、EDS和XRD等对材料表面形貌及物相进行分析。 结果: 在SBF模拟体液中浸泡的样品在第8 d已经成分散的颗粒状,看不到完整的样品。而DMEM中样品却仍然可以保持完整形貌。SBF溶液中镁离子的释放量及钙离子消耗量明显高于DMEM溶液。2种腐蚀介质中pH变化没有太大的差异,最终的pH都维持在10.0左右。纯镁在2种腐蚀介质中生成的产物有很大的差别。在SBF 体系中,样品腐蚀产物主要是氢氧化镁,并出现了少量镁的磷酸盐沉淀。而在 DMEM 中,腐蚀产生了大量的磷酸一氢镁和磷酸镁,同时有少量的氢氧化镁结晶。 结论: 纯镁在2种体系中腐蚀速度差别很大,在SBF体系腐蚀速度明显大于DMEM体系中。纯镁在SBF体系和DMEM中不同时间点产生的腐蚀产物不同。

Objective: To observe the corrosion behavior of pure magnesium in different corrosive media,and explore the possible degradation mechanism. Methods: According to ASTM-G31-72 standard used simulated body fluid(SBF) and Dulbecco’s modify Eagle medium(DMEM)for immersion media to immerse pure magnesium. Measured calcium,magnesium ion concentration and system pH changes in the different time point. The changes of material surface morphology were investigated by scanning electron microscopy ,EDS and XRD. Results: After immersing 8 days,the samples in SBF could not observe the complete shape,while the samples’ shape were completed in DMEM.The magnesium ion release quantity and calcium consumption in SBF solution are obviously higher than that of the DMEM solution.The changes of pH in two kinds of corrosion medium did not present too big difference,and the pH was maintained at about 10.0 finally.The product of pure magnesium which soaked in the two kinds of corrosion medium presented big difference. Samples’ surface in the SBF system generated magnesium hydroxide,and emerged a small amount of magnesium phosphate precipitation. While in DMEM,there has been a lot of magnesium monohydrogen phosphate,magnesium phosphate ,and a small amount of magnesium hydroxide crystals. Conclusion: The SBF system of the corrosion rate was significantly higher than DMEM.Pure magnesium corrosion products generated differently at different time points in the SBF system and DMEM.

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