【作者】 赵萱；

【导师】 蔡启舟；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2010， 硕士

【摘要】 硬骨替代产品的研发是组织工程领域的一个重要分支,钛作为综合性能良好的医用金属材料,是硬骨替代材料开发的一个重要产品。然而,医用钛无生物活性,在体内与组织形成的只是不牢固的机械嵌合。微弧氧化是一项可以在医用钛表面造孔、成膜的电化学技术,可增加其生物活性,使钛表面与组织形成牢固的化学结合,因而在医用钛表面改性方面具有良好的应用前景。本文在乙酸钙-磷酸二氢钙电解液体系中,分别采用微弧氧化-水热处理和微弧氧化-煅烧处理的工艺,在纯钛表面制备含有羟基磷灰石（Hydroxyapatite, HA）仿生陶瓷膜。利用SEM、EDX、XRD、厚度测量仪、划痕试验仪、恒电位测量仪、细胞接种等手段研究了膜层的形貌及元素组成、膜层物相组成、厚度、结合强度、耐蚀性和细胞相容性。比较了两种工艺条件下制备的仿生膜层的综合性能,并探讨了羟基磷灰石的形成机理,取得了如下结果。在乙酸钙-磷酸二氢钙电解液体系中,纯钛表面经过微弧氧化后形成了以TiO2为主的粗糙多孔的氧化物膜层。使用含有氨水的介质对该膜层进行水热处理后,膜层中出现了鳞状、层片状以及针棒状的HA,膜层厚度增加,且变得更为致密,膜层中Ca/P为1.68。HA的形成机制是微弧氧化膜为HA的形核提供了活性位点,而高压釜中的水热环境为HA的形核、生长提供了有利的环境。在乙酸钙-磷酸二氢钙电解液体系中添加硝酸镧后,微弧氧化膜层粗糙多孔,但出现了少量的细小裂纹。膜层主要由锐钛矿和金红石组成,并含有非晶相,经煅烧处理后证实为羟基磷灰石和磷酸钙陶瓷。煅烧处理后膜层厚度增加,裂纹加深,膜层中的Ca/P大于天然HA的Ca/P。在电解液中添加La,通过引起电荷的不平衡而促使碱性的TiO₂水凝胶层的形成,进而促进HA的形成。膜层结合力的测试结果表明:经过水热处理后,膜层结合强度优于水热处理前膜层的结合强度;在含镧电解液中得到的膜层结合强度优于不含镧电解液中得到的膜层,但煅烧处理使膜层的结合强度降低。膜层耐蚀性的试验结果表明,经过微弧氧化及后续处理所得的膜层表面耐蚀性均优于纯钛。微弧氧化膜层经水热处理后,其耐腐蚀性能有所降低,而煅烧处理后膜层的耐蚀性能有所提高。以细胞接种方式比较四种膜层和纯钛的细胞相容性,结果表明,经过微弧氧化及后续处理所得的膜层表面的细胞相容性均优于纯钛表面。水热处理可以提高膜层的细胞相容性,而煅烧处理则一定程度地降低了膜层表面的细胞相容性。更多还原

【Abstract】 The development of hard bone tissue is one major focus of tissue engineering. Medical titanium and its alloys are useful products in this field due to their excellent performance. However, the combination of titanium and the bone tissue is just a pure mechanical way within human body, which is rather unstable. Micro-arc oxidation （MAO） is a kind of electrochemical technique that can make the surface of titanium have a kind of porous coating and can improve the bio-activity of titanium. This technique has a bright future in the application of surface processing on titanium and its alloys because it can make a chemical connection between the surface of titanium and the bone tissues.In this paper, by using of Ca（CH3COO）2·H2O-Ca（H2PO4）2·H2O electrolyte, the bio-ceramic coatings with hydroxyapatite（HA） were prepared on pure titanium from two different technical routines: one is MAO and hydrothermal treatment routine and the other is MAO and calcination treatment routine. The surface/cross-sectional morphology, elemental composition, phase composition, thickness, adhesion, corrosion resistance and cyto-compatibility were investigated by using SEM, EDX, XRD, film thickness meter, film adhesion meter, CS300 constant potential rectifier, and cell culture method, respectively. Meanwhile, the comprehensive performance of the coatings formed by the two technical routines was compared, and HA forming mechanism was discussed, as well. The results are as following:Within the Ca（CH₃COO）₂·H₂O-Ca（H₂PO₄）2·H₂O electrolyte system, a kind of coarse and porous coating mainly with titania phase was gained on the surface of pure titanium after the MAO treatment. After hydrothermal treatment, it appeared scale, flaky or needle structures within the coating, which was thicker and denser than before. The ratio of Ca/P of this coating then is 1.68. The autoclave environment on the one hand provides nucleation sites for HA and on the other hand provides a promising environment for HA to nucleate.Within the Ca（CH₃COO）2·H2O-Ca（H₂PO₄）2·H₂O-La（NO₃）3·6H₂O electrolyte system, amorphous phases were gained within the coarse and porous coating after the MAO treatment. And it appeared some heat cracks within such coating. After the calcination treatment, the amorphous phases were tested to be HA and calcium phosphate ceramics. Calcination treatment has made the coating thicker and made the heat cracks deeper and wider. The ratio of Ca/P of this coating then is bigger than that same ratio of natural HA. Although the element of La did not form any new phase within the film, it played an important role in facilitating the formation of HA: it caused unbalanced electron charge, which led the TiO2 water gel to form and later prompted the formation of HA.According to the results of adhesion test, the adhesion of coatings performs better after the hydrothermal treatment; the adhesion of coatings gained from electrolyte with La performs better than that from electrolyte without La, but the calcination treatment makes the adhesion poorer. According to the results of corrosion resistance, all the coatings gained from MAO treatment with or without later treatment have better corrosion resistance performance than pure titanium. After the hydrothermal treatment, the MAO coating performs poorer corrosion resistance; while the calcination treatment, the coating gained from electrolyte with La exhibits better corrosion resistance.Cell-culture is used to compare the cyto-compatibility of four kinds of coatings prepared in this paper as well as pure titanium. The results show that all the coatings have better cyto-compatibility than pure titanium. Hydrothermal treatment can improve the cyto-compatibility performance of coatings, while calcination treatment to some degree lower the cyto-compatibility performance of coatings.更多还原