纳米羟基磷灰石对血管内支架用可降解Mg-Zn-Zr 合金性能的影响

Effects of Nanohydroxyapatite Addition on Properties of Mg-Zn-Zr Alloy for Biodegradable Intravascular Stents

摘要:

作为可降解血管内支架材料的探索，制备了Mg-3Zn-0.8Zr合金(质量分数，%,下同)及Mg-3Zn-0.8Zr-1HA复合材料，研究了纳米羟基磷灰石(n-HA)对合金力学性能和生物腐蚀降解性能的影响。n-HA均匀分布于镁合金基体中，使晶粒细化，抗拉强度和延伸率均高于未添加n-HA合金。模拟体液(SBF)浸泡实验表明：随着浸泡时间延长，两种材料表面形貌差异明显。浸泡20 d后，含n-HA的复合材料表面完整，有Ca、P沉积层形成，电化学测试计算的电流密度为0.701×10-5A·cm-2；而不含HA的合金表面严重脱落形成凹坑，对应腐蚀电流密度为1.034×10-5A·cm-2，显示n-HA显著增加了镁合金的耐腐蚀能力

Abstract:

To explore biodegradable intravascular stents, Mg-3Zn-0.8Zr-1HA composite (mass fraction, similarly hereinafter) and Mg-3Zn-0.8Zr alloy were prepared to investigate the effects of nanohydroxyapatite (n-HA) on the mechanical and biodegradable properties of Mg-3Zn-0.8Zr alloy. Results indicate that the n-HA particles are distributed uniformly in the matrix, so the grains of the matrix are refined, and the ultimate tensile strength and elongation are increased. The immersion tests in the simulated body fluid (SBF) show that the surface morphologies of the two kinds of materials are quite different as the immersion time is prolonged. After immersion for 20 d, the surface of the composite with n-HA is still perfect and covered with Ca and P, while a lot of pitting occurs on the surface of Mg-3Zn-0.8Zr alloy. The electrical current densities of the composite and the alloy are 0.701×10-5 A·cm-2 and 1.034×10-5 A·cm-2 respectively, which demonstrates that the corrosion resistance of the Mg alloy is significantly improved by the addition of nanohydroxyapatite powders.