【作者】 李鹏；

【导师】 张雅静；

【作者基本信息】 东北大学 ， 材料加工工程， 2014， 硕士

【摘要】 镁及镁合金材料具有良好的生物相容性,具有与人骨非常匹配的力学性能,且可以在人体内降解,是一种很有潜力的医用植入材料。但是,镁合金能否成为医用可降解材料的关键在于控制材料降解速度与组织新生或者愈合速度之间的匹配,故镁基材料在生理环境下的腐蚀降解过程和机制、过程控制方法等问题还有待进一步研究。本实验采用铸造、热处理和热挤压技术,制备了Mg-3.0wt%Zn-0.5wt%Sr合金与Mg-3.0wt%Zn-1.5wt%Sr合金,研究了合金元素Sr对合金显微组织以及合金的力学性能的影响。采用仿生法在Mg-Zn-Sr合金表面制备羟基磷灰石(HA)涂层,研究了合金有无涂层试样在人体模拟液(SBF)中的电化学性能以及浸泡腐蚀降解行为,结果表明：(1)制备的Mg-3.0wt%Zn-0.5wt%Sr和Mg-3.Owt%Zn-1.5wt%Sr合金的密度分别为1.760g·cm-3、1.771g·cm-3,屈服强度分别是250MPa、198MPa,弹性模量分别为47.41GPa、49.79GPa,延伸率分别为9.68%、13.12%,抗拉强度分别是295MPa、275MPa,抗压强度分别是450.34MPa、447.07MPa。(2)利用仿生沉积法在Mg-Zn-Sr合金表面成功制备均匀致密的HA涂层。(3)Mg-3.0wt%Zn-0.5wt%Sr合金有无涂层试样的电化学腐蚀电位分别为-1.528V,-1.637V,电流密度分别为2.73×10-5A·cm-2,2.75×10-4A·cm-2,极化电阻分别为225Ω,55Ω; Mg-3.0wt%Zn-1.5wt%Sr合金有无涂层试样的电化学腐蚀电位分别为-1.634V,-1.719V,电流密度分别为2.94×10-5A·cm-2,4.33×10-4A·cm-2,极化电阻分别为170Q,40Ω; Mg-3.0wt%Zn-0.5wt%Sr合金耐腐蚀性较Mg-3.0wt%Zn-1.5wt%Sr合金好；涂层有效的提高了合金的耐腐蚀性能。(4) Mg-Zn-Sr合金有无涂层试样在SBF中析氢量随着时间的增加而增加,析氢速率随着时间的增加而降低,有涂层试样的析氢速率远低于无涂层试样的析氢速率,涂层降低了合金的腐蚀速率。(5) Mg-Zn-Sr合金有无涂层试样在SBF中浸泡时间越长,失重率越大,但有涂层试样的失重率远小于无涂层试样的失重率,有涂层试样的耐蚀性比无涂层试样的耐蚀性强。(6)HA涂层降低了Mg-Zn-Sr合金在SBF中的降解速率。(7) Mg-3.0wt%Zn-0.5wt%Sr合金的综合性能好于Mg-3.Owt%Zn-1.5wt%Sr合金。更多还原

【Abstract】 Magnesium and magnesium alloys have good biocompatibility, mechanical properties of matching human bone and degradation in vivo, therefore they are potential medical implant materials. However, The key magnesium alloy can become a medical degradable material is to control the degradation and tissue of newborn or matching healing, so the problem of Mg based materials corrosion degradation process and mechanism, in the physiological environment of the process control methods have yet to be further studied.Mg-3.0wt%Zn-0.5wt%Sr alloy and Mg-3.0wt%Zn-1.5wt%Sr alloy were prepared by casting and hot extrusion technology, studied the effect of two kinds of the mechanical properties of alloys and alloying elements on Microstructure of Sr alloy. HA coating on the surface of Mg-Zn-Sr alloy was prepared by biomimetic method, studied the alloy bare and coated specimen in the simulated body liquid (SBF) in the electrochemical performance and corrosion behavior, results show that:(1) The density of Mg-3.Owt%Zn-0.5wt%Sr alloy and Mg-3.0wt%Zn-1.5wt%Sr alloy is1.760g.cm-31.771g.cm-3, yield strength is250MPa,198MPa, the elastic modulus is47.41GPa,49.79GPa, the elongation is9.68%、13.12%, the tensile strength is295MPa,275MPa, the compressive strength is450.34MPa、447.07MPa.(2)The uniform and dense HA coating is successful prepared on the surface of Mg-Zn-Sr alloy by using biomimetic method.(3) Electrochemical corrosion potential of Mg-3.0wt%Zn-0.5wt%Sr alloy with and without coating is-1.528V,-1.673V, current density is2.73×10-5A.cm-2,2.75×10-4A.cm-2, corrosion resistance is225ohm,55ohm; Electrochemical corrosion potential of Mg-3.0wt%Zn-1.5wt%Sr alloy with and without coating is-1.634V,-1.719V, the current density is2.94×10-5A·cm-2,4.33×10-4A·cm-2, corrosion resistance is170ohm,40ohm; The coating can improve the corrosion resistance of alloy and the corrosion resistance of Mg-3.0wt%Zn-0.5wt%Sr alloy is better than that of Mg-3.0wt%Zn-1.5wt%Sr alloy.(4) Mg-Zn-Sr alloy with and without coating specimens in SBF hydrogen amount increased with the increase of time, the hydrogen evolution rate decreases with the increase of time, the hydrogen evolution rate of coating specimens is far lower than the hydrogen evolution rate of uncoated specimens, the coating reduces the corrosion rate of the alloy.(5) Mg-Zn-Sr alloy with and without coating specimens in SBF immersion time is longer, the greater weight loss rate, but the rate of weight loss rate of coating specimens is far less than the uncoated samples, the corrosion resistance of coated specimen than the uncoated specimen corrosion resistance.(6) The HA coating decreased the corrosion rate of Mg-Zn-Sr alloy in SBF.(7) The comprehensive properties of Mg-3.0wt%Zn-0.5wt%Sr alloy is better than Mg-3.0wt%Zn-1.5wt%Sr alloy.更多还原