钛及钛合金本身具有比强度高、生物相容性和耐腐蚀性优良的性能，是迄今为止骨骼及牙齿等硬组织最好的替代材料，具有广阔的应用前景。但它与骨之间只是一种机械嵌合的骨结合，耐磨性较差，易向肌体释放金属离子，因而对钛合金表面改性以完善其生物学性能引起了人们的日益重视。钛及钛合金微弧氧化(micro-arc oxidation，简记为MAO)可在钛及钛合金表面产生一种多孔的、与基质结合牢固的、具有陶瓷特性的氧化物，这层氧化物与钛合金基体相比，其耐磨、耐蚀、电绝缘等性能得到明显的改善。 本论文论述了通过改变微弧氧化顺序在钦合金表面制备含钙磷生物陶瓷膜及通过微弧氧化直接合成羟基磷灰石生物陶瓷的方法，并研究了Ti-6Al-4V微弧氧化顺序、微弧氧化电流密度和微弧氧化时间等参数对涂层形貌、元素和相组成的影响，给出了两种试验条件下的最佳氧化顺序、电解液成分和工艺参数。在此基础上，采用扫描电镜(SEM)、X射线衍射仪(XRD)和能谱仪分析了涂层的形貌、相及元素组成。采用显微硬度计、MM-200型摩擦磨损试验机和LK9805电化学分析仪研究了涂层的硬度、摩擦磨损和腐蚀等性能。 采用体内急性全身毒性实验、溶血实验、口腔粘膜实验、MTT细胞毒性实验、体外溶解实验对钛合金表面生物涂层的生物安全性进行了评价。结果表明： Ti-6Al-4V经微弧氧化形成的致密层未见任何急性毒性反应；溶血程度为0.918%～0.938%，有良好的血液相容性；细胞毒性实验评价级别为0级，无明显的细胞毒性作用；口腔粘膜实验，未发现异常。由以上结果可以初步认为Ti-6Al-4V经两种方法生成的生物陶瓷膜是理想的生物材料。 论文对两种方法制备的生物陶瓷膜的合成机理进行了探讨，认为改变微弧氧化顺序生成的生物陶瓷膜的主要机理是电泳方式；通过微弧氧化直接合成羟基磷灰石的机理是：在初始阶段钙离子向阳极运动采用的是扩散的方式，当电流逐渐增大后，钙离子向阳极运动采用的是电泳方式。 关键词：钛合金，微弧氧化，生物陶瓷涂层，磨损，腐蚀，生物相容性

 Titanium and titanium alloy have the excellent properties of high strength, biocompatibility and corrosion resistance. So far, they have become the best substituting materials of hard organizations, such as bone and tooth. However, because of their poor binding capacity with bone and wear resistance, it has aroused people's attention day by day that the surface modification of titanium alloys is carried out in order to improve their biological properties. Micro-arc oxidation of titanium and titanium alloy can synthesize a porous oxide layer on their surfaces, which bonds strongly with the substrate and has ceramic properties. Compared with the substrate, the wear resistance and corrosion resistance of this oxide layer have been obviously improved. Bioceramic coating by micro-arc oxidation regards the coating containing Ca and P as a typical representative, especially, the hydroxyapatite coating has more excellent biocompatibility. Therefore, the synthesis of bioceramic coating on titanium alloy by micro-arc oxidation has theoretical significance and practical value. In this paper, the bioceramic coatings were prepared using micro-arc oxidation method with two different ways, i.e., the bioceramic coating containing Ca and P was synthesized by changing the order of micro-arc oxidation, and the bioceramic coating containing hydroxyapatite was directly synthesized by micro-arc oxidation. The following aspects were systematically studied: First of all, it was found that the order of micro-arc oxidation can influence the surface morphologies of bioceramic coating on titanium alloy for the first time. The bioceramic coating containing Ca and P element were obtained by changing the order of micro-arc oxidation for the first time. The coating containing α-Ca(PO₃)₂ and CaTiO₃ phase which possess better biocompatibility were successfully synthesized. The influence of the order of micro-arc oxidation on bioceramic coating on titanium alloy was studied. The influences of the parameters such as the order of micro-arc oxidation, the composition of electrolyte, time, and current density on the morphology, phase structure, and elemental composition of the coating surface were synthetically analysized. The synthesis mechanism that the bioceramic coating on titanium alloy was prepared by changing the order of micro-arc oxidation was studied. The results showed: 1.In 4 groups of different electrolytic solutions of C₄H₆O₄Ca, Ca(NO₃)₂, (NaPO₃)₆, Na₃PO₄, 8 groups of micro-arc oxidation coating with different morphologies were obtained by changing the order of micro-arc oxidation. Through analyzing the uniformity degree, pore size and pore connectivity of the coating, it can be concluded that the coating surface quality on titanium alloy prepared by the sequence of sodium hexametaphosphate-calcium acetate was better than other coatings. 2.8 groups of Ca(NO₃)₂-(NaPO₃)₆, (NaPO₃)₆-Ca(NO₃)₂, Ca(NO₃)₂-Na₃PO₄, Na₃PO₄-Ca(NO₃)₂, C₄H₆O₄Ca-(NaPO₃)₆, (NaPO₃)₆-C₄H₆O₄Ca, C₄H₆O₄Ca-Na₃PO₄, and Na₃PO₄-C₄H₆O₄Ca of coatings contained Ca and P element, and contained electrolyte elements (such as W, Al and Ti, etc) and matrix elements at the same time. But the difference between every element contents was relatively large. The coating contained mainly TiO₂ phase. Among them, the coating prepared by the sequence of sodium hexametaphosphate-calcium acetate contained α-Ca(PO₃)₂ and CaTiO₃ phases, and their biological activities were better. 3.With the increase of the micro-arc oxidation time and current density, the microporous quantity of the coating surface became more, and then became less again; the pore size changed from small to big, and the porosity became great. P content in the coating reduced gradually, Ca content increased gradually, and Ca/P increased. The largest thickness of the coating reached 70-80μm in this study. 4.The microhardness of the coating containing Ca and P was relatively large, and its biggest value reached 800HV〓, which was well more than the microhardness (200-300HV〓) of matrix. With the increase of the current density, the microhardness of the coating increased constantly, and then reduced gradually. 5.The wear resistance of the coating containing Ca and P by hexametaphosphate-calcium acetate technics was better than that of matrix alloy. With the increase of the current density, the wear resistance of the coating was strengthened gradually. 6.The corrosion resistance of the coating containing Ca and P in the simulated body fluid and simulated saliva was superior to that of matrix. With the increase of the current density, the corrosion potential of the coating increased gradually, and the corrosion current of the coating reduced firstly, and then increased. The complete dipping test revealed that the corrosion rate of the coating was wholly lower than that of titanium alloy. Secondly, the new breakthrough on the technology utilizing micro-arc oxidation to directly synthesize bioceramic coating containing hydroxyapatite was obtained. The stabilization of pH value of micro-arc oxidation electrolyte was successfully achived utilizing additive, the technique for directly preparing HA utilizing micro-arc oxidation was developed, and the influences of the adding sequence of solution on the bioceramic coating was also discussed. Through studying the influences of electrolyte composition, pH value of the solution, additives, electric parameters, and oxidation time on the coating surface morphology, phase structure and elemental composition, the mechanism utilizing micro-arc oxidation to directly synthesize bioceramic coating containing hydroxyapatite was revealed. The friction and wear properties of the coating containing hydroxyapatite were studied. The results showed that: 1.In the course of the micro-arc oxidation, the pH value, additive, electric parameters, oxidation time of the solution have important influence on the synthesis of hydroxyapatite. The pH value and additive of the solution determined the stability of the electrolyte; the electric parameters and oxidation time determined the ratio of Ca and P of the coating. Only when the ratio of Ca and P reached 2, is there the emergence of hydroxyapatite, and simultaneously Ca₃(PO₄)₂ generated. With the increases of the oxidation time and current density, Ca₃(PO₄)₂ became gradually amorphous phase. 2.The friction coefficient of coating containing hydroxyapatite was first increased and then decreased with friction time; and the friction coefficient was first decreased and then increased when electricity density. Finally, the biological properties of the biological coatings prepared using two different methods were studied. The acute toxicity test, hemolysis experiment, oral mucosa stimulation experiment, cell toxicity test, and coating dissolution experiment were carried out, respectively. The results showed: 1.The bioceramic coatings prepared by the two different methods had no acute toxicity reaction, the hemolysis rate was all less than one, the cell toxicity was all 0, and the coatings had no stimulating effects. From the point of view of the biocompatibility, the bioceramic coatings prepared by the two different methods were ideal biological materials. 2.When the coating containing Ca and P prepared by hexametaphosphate -calcium acetate technics and the coating containing HA were dissolved in distilled water, The overall changing trend of Ca²⁺ concentration in the distilled water was first rising and then descending. When the dissolved time in the distilled water was beyond 110 hours, the Ca²⁺ concentration of the coating containing HA was obviously higher than that containing Ca and P. The coating containing Ca and P in distilled water grew mainly in sheet materials, while the coating containing hydroxyapatite grew mainly in granular materials. Keywords: Titanium alloy, Micro-arc oxidation, Bioceramic coating, Wear, Corrosion, Biocompatibility