摘要:随着科学技术的进步和现代医疗领域的拓展，传统的医用生物材料已经不能满足人们的需要，新型复合生物材料受到越来越多的重视。镁合金具有优良的生物相容性和在人体环境下的可降解性，并且具有与人骨匹配的力学性能（密度和弹性模量与人骨接近，比强度和比刚度较高），近年来在医学领域受到了广泛的关注。但镁合金在人体环境中耐蚀性差，降解速度快，在生物受损组织愈合之前就失去了其原来的力学性能，因此不能满足生物植入材料的要求，使其在临床医学方向应用受到一定程度的限制。本文着重研究在镁合金表面制备微弧氧化和电泳沉积复合膜层，与单一的微弧氧化膜层对比，通过一系列的微观结构观察和膜层性能测试分析，比较两种膜层的组织和性能特点，为镁合金在生物医学领域的临床应用做拓展性研究。

本文采用ZK60镁合金为研究对象，通过水磨对镁基体表面进行预处理，通过优化后的工艺参数，制备微弧氧化膜层。微弧氧化工艺采用恒流模式，电流密度为10A/dm2，处理时间13min。为了进一步提升微弧氧化膜层的生物活性和耐蚀性，采用电泳沉积(ED)法在MAO膜层上沉积纳米级羟基磷灰石(HA)制备微弧氧化一电泳沉积(MAO-ED)复合膜层。电泳沉积阴极为微弧氧化试样，阳极为薄不锈钢片，电泳液为10g/L羟基磷灰石的悬浮液，将阴极和阳极置于电泳液进行电泳，完成后进行250°C的烧结固化处理。通过SEM、XRD等仪器对MAO和MAO-ED膜层的微观形貌、物相、孔隙率、耐蚀性等性能进行分析。将两种膜层进行为期20天的模拟体液(SBF)浸泡实验，选取5天、10天、15天、20天四个时间点，进行膜层微观形貌观察、溶液pH变化、试样失重测试、物相和元素含量变化等研究，进一步对膜层在生物环境下的耐蚀性与生物活性做系统性研究分析。

通过实验发现微弧氧化膜层对基体镁合金具有保护作用，但其表面疏松多孔的特性为Cl-等介质提供了大量腐蚀通道，腐蚀介质可以通过微孔腐蚀基体，降低了其耐蚀性。通过电泳沉积封堵微弧氧化膜层的放电孔洞，使HA在放电通道中沉积，改善了微弧氧化膜层的致密性和耐蚀性。通过浸泡实验发现，复合膜层在浸泡初期表面快速形成诱导产物(碳酸盐、磷酸盐等)，且含量逐渐增加。HA膜层稳定性较好，在为期20天的浸泡实验中膜层未发生破裂。

关键词：镁合金；电泳沉积；耐蚀性；生物活性；

Abstract:With the development of science and technology and modern medical technology, the traditional medical biomaterials can no longer meet people's needs, so the new composite material has been paid more and more attention. Magnesium alloys have excellent biocompatibility and biodegradability in the human environment, and have a mechanical properties (human and bone close to the human body, the specific strength and specific rigidity), in recent years In the field of medicine has been widespread concern. However, the corrosion resistance of magnesium alloy in the human body is poor, the  degradation rate is fast, and its original mechanical properties are lost before the damaged tissue is damaged. Therefore, it can not meet the service requirements and make its application to be limited to a certain extent. In this paper, we focus on the preparation of micro-arc oxidation and electropHoretic deposition on the surface of magnesium alloy, and  compare it with a single micro-arc oxidation film. Through a series of performance tests, we can compare the microstructure and performance characteristics of the two films Research on Improving Corrosion Resistance and Bioactivity of Magnesium Alloy in Biological Environment.

In this paper, ZK60 magnesium alloy was used as the research object, and the micro-arc oxidation was carried out after removing the surface oxide by water mill. The micro-arc oxidation coating was prepared by optimizing the process parameters. In the process of micro-arc oxidation, the constant current mode of 1.2A current was used, the treatment time was 13min, and the surface change of magnesium alloy was observed during micro-arc oxidation and analyzed. In addition, in order to further enhance the bioactivity and corrosion resistance of the micro-arc oxidation film layer, nano-sized hydroxyapatite (HA) can be deposited on the MAO coating by electropHoretic deposition (ED) to prepare micro-arc oxidation An electropHoretic deposition (MAO-ED) composite coating. ElectropHoresis solution electropHoresis solution for the concentration of 10g / L hydroxyapatite plus ethanol (dispersant), then the cathode and anode placed in the electropHoresis solution for electropHoresis. The surface morpHology and pHase of MAO and MAO-ED films were analyzed by SEM and XRD. The corrosion resistance and bioactivity of the films were compared.