摘要随着材料科学技术的进步，镁合金以其优越的力学性能和生物可降解性而逐渐成为生物医用材料领域里的研究热点。羟基磷灰石（HA）是目前研究最为广泛的生物陶瓷材料，具有良好的生物相容性和骨诱导能力，而纯的HA植入体力学性能较差，故将其以涂层形式与镁合金基体相结合是目前材料表面改性中的研究重点。基于上述认识，本课题从提高镁合金基体的耐蚀性及生物活性的角度出发，创新性地提出在微弧氧化（MAO）的基础上利用等离子喷涂法(APS)制备含HA的生物复合膜层。86870

首先，从电源控制模式考虑，采用恒压、恒流、恒压+恒流三种电源控制模式，在生物电解液体系中对ZK60Mg合金进行微弧氧化处理。综合考虑不同电源模式下膜层的表面形貌、粗糙度及孔径大小，分别选取了恒压500V、恒流1。0A、恒压400V+恒流1。5A时制备的膜层为最佳膜层，最为符合等离子制备HA涂层的要求，即膜层表面具有一定粗糙度（Rz≥20）、孔径大小（2~10μm）。继而对三种不同模式下的最佳膜层进行耐蚀性分析，选取恒流1。0A下获得的膜层为耐蚀性最佳膜层，并将其作为基底层，使用等离子喷涂技术制备含HA的生物复合膜层。

通过单变量法优化等离子喷涂制备含HA的生物复合膜层的工艺参数，主要研究了不同喷涂距离对生物复合膜层的影响。研究发现，当喷涂距离设置为100mm时，HA粉末在喷涂过程中熔化状态最佳。XRD物相分析表明，在等离子喷涂过程中，HA粉末发生了分解反应，主要物相包括HA、CaO、Ca3(PO4)2、MgO以及部分ACP。

复合膜层的耐蚀性测试表明，等离子喷涂过程中，熔化的HA粉末粒子显著地封住了微弧氧化后表面的孔洞，进而有效地抑制了腐蚀介质的进入，大幅度地提高了镁合金基体的耐蚀性。

毕业论文关键词: ZK60镁合金；MAO/APS；生物复合膜层；制备

Abstract With the development of material science, magnesium alloy has gradually become research hotspot in the field of biomedical materials for its superior mechanical properties and biodegrade ability。 Nowadays, Hydroxyapatite (HA) has been widely researched in biomedical field due to its good biological compatibility and bone induction ability。 However, the mechanical properties of pure HA implants are poor。 Therefore, the combination of coating with substrate of magnesium alloy is the focus of research in the field of material surface modification technology。 Based on the above understanding, in order to enhance corrosion resistance and biological activity of magnesium alloy, this paper creatively put forward a new method of preparing biological composite layer containing HA by Atmospheric Plasma Spraying (APS) on the basis of Micro Arc Oxidation (MAO)。

First of all, from the perspective of power control mode, the MAO coating was prepared in a basic biologic electrolyte on ZK60 magnesium using three different kinds of power control modes including constant voltage mode, constant current mode and constant voltage-constant current mode。 For sake of acquiring the best surface state which is the requirement of preparing HA coating using APS (Rz≥20 μm, the size of pore is about 2~10μm), the surface morphology, roughness and pore size of the coatings under different power control modes were analyzed。 Then on the basis of three optimized coatings with the best surface state, the coating formed under constant current 1。0A was selected to be a basal layer of preparation of composite biological layer containing HA using APS due to the results of corrosion resistance test。 

To optimize the APS process parameters of preparing composite biological coatings containing HA, this paper used single variable method which mainly researched the effect of different stand-off distance upon composite biological layer。 It was found that when the spraying distance was 100mm, the HA powder well melted during plasma spraying process。 XRD phase analysis shows that, in the process of plasma spraying, HA powder has a decomposition reaction, the main phase includes HA, CaO, Ca3 (PO4) 2, MgO and part ACP。