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在室温下,将Mg-0.5Ca合金在不同浓度的氢氧化钠和HF溶液浸渍不同的时间,研究HF处理对合金腐蚀行为的影响。采用原子力显微镜、X射线衍射、场发射扫描电子显微镜表征样品的微观组织变化。通过动电位极化和Kokubo溶液浸泡试验测试样品的耐腐蚀性。结果表明,与35%HF处理的样品相比,经40%HF溶液处理的Mg-0.5Ca合金具有更均匀、更致密、更薄的涂层(12.6μm)。电化学测试表明,在Kokubo溶液中,经氟化物处理的Mg-0.5Ca合金样品的耐腐蚀性比未处理样品的高35倍;前者的体外降解速率远远低于后者的。在40%HF溶液处理过的样品表面只出现了一些腐蚀点,而未经处理的样品完全被腐蚀产物覆盖且出现了分层现象。40%HF处理的Mg-0.5Ca合金,具有低的降解速率和良好的生物相容性,是一种有潜力的植入材料。
At room temperature, Mg-0.5Ca alloy was immersed in different concentrations of sodium hydroxide and HF solution for different time to study the effect of HF treatment on the corrosion behavior of the alloy. The microstructural changes of the samples were characterized by atomic force microscopy, X-ray diffraction and field emission scanning electron microscopy. The corrosion resistance of the samples was tested by potentiodynamic polarization and Kokubo solution soak test. The results show that the Mg-0.5Ca alloy treated with the 40% HF solution has a more uniform, denser, thinner coating (12.6 μm) than the 35% HF treated sample. Electrochemical tests showed that corrosion resistance of the fluoride-treated Mg-0.5Ca alloy samples in the Kokubo solution was 35 times higher than that of the untreated sample; the degradation rate of the former in vitro was much lower than that of the latter. Only a few corrosion spots appeared on the surface of the 40% HF solution-treated sample, whereas the untreated sample was completely covered with the corrosion product and delaminated. The 40% HF-treated Mg-0.5Ca alloy is a promising implant material with low degradation rate and good biocompatibility.