Abstract One of the promising applications of magnesium and magnesium alloys is their use as biodegradable implants in biomedical applications. The pH around an orthopedic implant greatly affects the degradation kinetics of biodegradable Mg–Ca alloys. At the location of a fracture, local pH changes, and this has to be considered in the optimization of implant materials. In this study, the effect of the pH of a physiological buffer on degradation of a Mg–0.8Ca alloy was studied. The pH of Hank’s balanced salt solution (HBSS) was adjusted to 1.8, 5.3 and 8.1. Degradation of a Mg–0.8Ca implant was tested using immersion test and electrochemical techniques. Immersion tests revealed an initial weight gain for all samples followed by weight loss at extended immersion time. Weight gain was highest at acidic pH (1.8) and lowest at alkaline pH (8.1). This was in agreement with results from electrochemical polarization tests where the degradation rate was highest (7.29 ± 2.2 mm/year) at pH 1.8 and lowest (0.31 ± 0.06 mm/year) in alkaline medium of pH 8.1. The pH of all HBSS buffers except the most acidic (pH 1.8) reached a steady state of ∼pH 10 at the end of the two-month immersion period, independent of the initial pH of the solution. Corrosion products formed on the sample surfaces were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and X-ray diffractometry (XRD), revealing the formation of magnesium and calcium phosphates with distinct morphologies that were different for each of the pH conditions. Thus, pH of physiological buffers has a significant effect on the degradation and corrosion of Mg–Ca alloys used for biomedical applications.

中文翻译：

---

pH 值对用于骨科植入物的 Mg-0.8Ca 合金降解动力学的影响

摘要 镁和镁合金有前景的应用之一是它们在生物医学应用中作为可生物降解的植入物的用途。骨科植入物周围的 pH 值极大地影响了可生物降解的 Mg-Ca 合金的降解动力学。在骨折位置，局部 pH 值发生变化，在优化植入材料时必须考虑到这一点。在本研究中，研究了生理缓冲液的 pH 值对 Mg-0.8Ca 合金降解的影响。Hank 平衡盐溶液 (HBSS) 的 pH 值调整为 1.8、5.3 和 8.1。使用浸入测试和电化学技术测试了 Mg-0.8Ca 植入物的降解。浸泡测试显示所有样品的初始重量增加，然后在延长浸泡时间后重量减少。体重增加在酸性 pH (1.8) 时最高，在碱性 pH (8.1) 时最低。这与电化学极化测试的结果一致，其中降解率在 pH 1.8 时最高 (7.29 ± 2.2 毫米/年)，在 pH 8.1 的碱性介质中最低 (0.31 ± 0.06 毫米/年)。除了最酸性的（pH 1.8）外，所有 HBSS 缓冲液的 pH 在两个月的浸泡期结束时都达到了 ～pH 10 的稳定状态，与溶液的初始 pH 无关。通过扫描电子显微镜 (SEM)、能量色散谱 (EDX) 和 X 射线衍射仪 (XRD) 研究了在样品表面形成的腐蚀产物，揭示了磷酸镁和磷酸钙的形成，这些磷酸镁和钙具有不同的形态，每种形态都不同。 pH条件。因此，生理缓冲液的 pH 值对用于生物医学应用的 Mg-Ca 合金的降解和腐蚀具有显着影响。