Deposition of layered bioceramic hydroxyapatite/TiO2 coatings on titanium alloys using a hybrid technique of micro-arc oxidation and electrophoresis
Deposition of layered bioceramic hydroxyapatite/TiO2 coatings on titanium alloys using a hybrid technique of micro-arc oxidation and electrophoresis
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DOI：
10.1016/s0257-8972(99)00612-x
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发表时间：
2000-03-01
影响因子：
5.4
通讯作者：
Matthews, A
中科院分区：
文献类型：
--
作者：
Nie, X;Leyland, A;Matthews, A
钛合金在几种生物植入物应用中取得了一些成功。然而，它们也有一定的缺点，比如较差的骨诱导性能和较低的耐腐蚀性。克服第一个缺点的尝试包括用生物陶瓷材料羟基磷灰石（HA）涂覆金属，羟基磷灰石是骨的主要成分，也是一种非常好的骨诱导剂。由于TiO2涂层也被认为是有效的化学屏障，可以阻止金属离子从植入物中释放出来，因此在钛合金上涂上双层HA-TiO2涂层，以HA为顶层，致密的TiO2膜为内层，应该具有很好的生物活性、化学稳定性和机械完整性的组合。本文介绍了应用微放电氧化（MDO）和电泳沉积混合处理提高种植体生物相容性和耐久性的努力。衬底材料采用最常见的结构钛合金（Ti-6Al-4V）。采用磷酸盐溶液和透明质酸粉末水悬浮液分别作为微弧氧化电解质和透明质酸电泳沉积溶液。结果表明，通过对钛进行阳极微氧化，可以得到较厚、较硬的TiO2涂层；通过等离子体电解和电泳相结合，可以同时在TiO2层的顶部形成HA涂层，悬浮体保持在较高的ph值。利用扫描电镜（SEM）和傅里叶变换红外光谱（FTIR）研究了涂层的微观结构和形貌。涂层与基材之间的粘接强度用划痕粘接试验进行了评估。在缓冲的生理溶液中使用电位试验来检测样品的耐腐蚀性。结果表明，微氧化和电泳混合沉积可以提供相纯的HA顶层和防腐的TiO2中间层，在人体腐蚀环境中应具有良好的机械和生化稳定性。(C) 2000 Elsevier Science S.A.版权所有
Titanium alloys have been used with some success in several bioimplant applications. However, they can suffer certain disadvantages, such as poor osteoinductive properties and low corrosive-wear resistance. Attempts to overcome the first of these drawbacks have involved coating the metal with the bioceramic material hydroxyapatite (HA), a primary component of bone and a very good osteoinductor. Since TiO2 coatings are also known to be effective as chemical barriers against the in-vivo release of metal ions from the implants, a double layer HA-TiO2 coating on titanium alloys with HA as the top layer and a dense TiO2 film as the inner layer should possess a very good combination of bioactivity, chemical stability and mechanical integrity.This paper describes efforts to improve implant biocompatibility and durability by applying a hybrid treatment of micro-are discharge oxidation (MDO) and electrophoretic deposition. The most common structural titanium alloy (Ti-6Al-4V) was used as the substrate material. A phosphate salt solution and an HA powder aqueous suspension were used as the electrolyte for micro-arc oxidation and the solution for HA electrophoretic deposition, respectively. It is shown that a relatively thick and hard TiO2 coating can be produced by anodic micro-are oxidation of titanium, and an HA coating incorporated on top of the TiO2 layer can simultaneously be formed using a combination of plasma electrolysis and electrophoresis, with the suspension held at high values of pH.X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) have been used to investigate the microstructure and morphology of the coatings. The adhesive strength between the coating and substrate has been assessed using scratch adhesion testing. The corrosion resistance of the specimens was examined using potentiodynamic tests in a buffered physiological solution. The results indicate that a hybrid combination of micro-are oxidation and electrophoretic deposition can provide a phase-pure HA top layer and anticorrosive TiO2 interlayer, which should show good mechanical and biochemical stability in the corrosive environment of the human body. (C) 2000 Elsevier Science S.A. All rights reserved.