【作者】 葛振东；

【导师】 赵红；

【作者基本信息】 大连理工大学 ， 材料学， 2009， 硕士

【摘要】 钛及镍钛（NiTi）合金由于具有良好的生物相容性、力学性能等而被广泛应用于人体硬组织替代材料,NiTi还应用于血管支架材料。但是,钛及镍钛合金表面不能直接与人体骨组织形成化学键合,且NiTi合金存在Ni²⁺离子毒性、表面血栓等问题。在植入体材料表面制备羟基磷灰石（HA）类骨成分涂层已表明具有良好的生物相容性及骨引导性。但是HA的脆性大,涂层结合力弱,易于脱落。微弧氧化（MAO）是一种制备金属氧化物微孔涂层的方法,制备的涂层具有耐蚀性好,结合强度高等特点。本文为了提高钛及镍钛合金的生物相容性,利用微弧氧化法在钛及镍钛合金表面制备含HA（或钙磷成分）和二氧化钛（TiO₂）的微孔涂层。选择醋酸钙（（CH₃COO）₂Ca·H₂O）和磷酸二氢钠（NaH₂PO₄·2H₂O）混合溶液作为电解液,通过控制微弧氧化电解液浓度、电参数,在钛合金表面制备HA/TiO₂复合多孔涂层;并将微弧氧化法与热处理、离子镀钛工艺相结合在NiTi表面制备微孔活性涂层。利用扫描电子显微镜（SEM）、电子探针（EPMA）、X射线衍射（XRD）、Raman光谱、表面能测试、电化学腐蚀测试等分析方法对涂层进行了结构及性能表征研究,并通过生物矿化试验对涂层的骨矿化能力进行了考察,通过血小板黏附实验考察了涂层的血液相容性。研究了电解液浓度及电参数对微弧氧化涂层组织结构的影响及不同电解液浓度下涂层的生物学性能。研究结果表明,涂层孔径与厚度随电解液浓度增大而增大,孔径的增大导致涂层表面能增大;当混合电解液中Ca/P比接近1.67,涂层中形成含HA的TiO₂相,涂层在Tris模拟体液中具有较好矿化能力与耐蚀性,涂层血小板黏附变形较小;随电参数的增大,涂层的孔径与厚度增大,涂层中锐钛矿相减少,金红石相增多,并且涂层中HA、Ca₃（PO₄）₂成分增多。研究了微弧氧化法与热处理、离子镀钛复合工艺在NiTi表面制备微孔涂层。结果表明:NiTi丝经500℃热处理后通过微弧氧化法可在表面形成含Ca、P的均匀微孔涂层,随微弧氧化时间延长,氧化层中Ti/Ni提高,Ca、P含量增大。电压550V,占空比15%,微弧氧化20s时,微孔均匀分布,孔径1μm左右,涂层有较好的血液相容性;NiTi经离子镀-微弧氧化处理在其表面形成以TiO₂为主的多孔涂层,涂层表面Ni含量保持在1%以内,表面的大颗粒随占空比的增大及时间的延长明显降低。电压520V,占空比15%,微弧氧化40s,表面微孔均匀,微孔尺寸1～2μm。涂层有较好的血液相容性。更多还原

【Abstract】 Titanium and Nitinol（NiTi） have been widely used as orthopedic implants because of their excellent mechanical properties and biocompatibility,NiTi also applies to vascular stent materials.However,the surface of titanium alloy can not be directly related to human bone tissue to form chemical bonding,and NiTi have issues of Ni²⁺ ion toxicity,thrombosis,and so on.The coating of hydroxyapatite（HA） on the implant surface has been suggested as the most effective way to provide biocompatibility and Osseo conductivity.But HA has shortcomings of brittleness,weak combination and easy off.Micro-arc oxidation（MAO） is a method to prepare metallic oxide-based micro porous coating with good corrosion resistance,high bond strength.In this paper,In order to improve the biocompatibility of titanium and nickel-titanium alloy,TiO₂ porous coatings with HA（or Ca,P component） were prepared on medical titanium and NiTi alloy by Micro-arc oxidation.The electrolyte solution of calcium acetate（（CH₃COO）₂Ca·H₂O） with sodium dihydrogen phosphate（NaH₂PO₄·2H₂O） was used to micro-arc oxidation.By controlling the electrolyte concentration,electrical parameters,HA/TiO₂ biocompatible porous coatings were prepared on the surface of titanium;and heat treatment,ion plating combination with micro-arc oxidation were used to prepare micro porous biological activity coatings on the surface of NiTi.Structure and Properties of coatings were characterized using SEM,EPMA, XRD,Raman spectroscopy techniques,as well as surface energy testing,electrochemical corrosion testing.Mineralization ability of coatings was studied by in vitro Mineralization test and blood compatibility of coatings was characterized by platelet adhesion test.The impact of the electrolyte concentration and electrical parameters to the structure of MAO coating and biological properties of different electrolyte concentrations were studied. The results show that pore size and thickness of coating increased with the augment of electrolyte concentration,and the augment of pore size could raise the surface energy.When the mole ratio of calcium to phosphate was controlled at 1.67 respectively,TiO₂ with HA formed in the surface of titanium.Coating has good corrosion resistance and mineralization ability in the Tris’ simulation body fluid.Platelets on the surface of the sample are neither distorted nor congregated,which shows superior blood compatibility.And the increasing of electrical parameters will make the pore size and thickness of coating increase,the anatase phase reduce,the rutile phase raise,as well as the increase of HA,Ca₃（PO₄）₂ components.The preparation of porous coatings on the surface of NiTi by heat treatment,ion plating combination with micro-arc oxidation was studied.The results show that uniform micro porous coating with Ca,P component formed on the surface of NiTi wires by MAO after heat treatment at 500℃.And the ratio of Ti/Ni and Ca,P content in coatings increased with the prolonged oxidation time.When voltage is 550V,duty cycle is 15%,well-distributed micro porous coatings were acquired by MAO treated for 20 seconds.The average pore size of micro porous on surface was about 1μm,and the platelet adhesion test showed superior blood compatibility of the coatings.A porous TiO₂-based coating formed on the surface of NiTi by micro-arc oxidation after ion plating,The Ni content of coating remained less than 1%,large particles in the surface significantly reduced with the increasing of duty cycle and extension of time.When voltage is 520V,duty cycle is 15%,uniform micro porous coating was formed after MAO treated for 40 seconds and pore size of surface was about 1～2μm,and the platelet adhesion test showed superior blood compatibility of the coatings.更多还原