Role of electrolyte chemistry on electronic and in vitro electrochemical properties of micro-arc oxidized titania films on Cp Ti
Role of electrolyte chemistry on electronic and in vitro electrochemical properties of micro-arc oxidized titania films on Cp Ti
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DOI：
10.1016/j.electacta.2013.05.032
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发表时间：
2013-08
影响因子：
6.6
通讯作者：
K. Venkateswarlu;N. Rameshbabu;D. Sreekanth;M. Sandhyarani;A. C. Bose;Muthupandi;S. Subramanian
中科院分区：
文献类型：
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作者：
K. Venkateswarlu;N. Rameshbabu;D. Sreekanth;M. Sandhyarani;A. C. Bose;Muthupandi;S. Subramanian
本工作的主要目的是研究微弧氧化二氧化钛膜的电子和体外电化学性能的Cp Ti，独立制作的各种电解质溶液中的阴离子，如磷酸盐（PO 43-），硼酸盐（B4 O 72-），柠檬酸盐（C6 H5 O 73-）和硅酸盐（SiO 32-）。进一步研究了阴离子对薄膜结构、形貌和组成的影响。采用微弧氧化技术，在恒电流模式下处理8 min。通过扫描电子显微镜（SEM）、能谱仪（EDS）和X射线衍射仪（XRD）对薄膜的表面形貌、元素分布、组成和结构特征进行了分析。在模拟体液（SBF）条件下（pH 7.4和37°C），通过计时电位和动电位极化测试研究了膜的热力学和动力学腐蚀性能。电化学阻抗谱（EIS）耦合等效电路建模进行分析的频率响应和莫特-肖特基分析进行研究的半导体（电子）性能的薄膜。根据ASTM B117标准进行盐雾加速腐蚀试验168 h，以基于目视检查证实样品的腐蚀和半导体性能。XRD结果表明，阴离子的加入强烈地影响了亚稳相向晶型稳定的金红石相的转变以及各相的晶体生长。SEM-EDS结果表明，薄膜中的磷含量在2.4at%~ 5.0at%之间，表明通过添加适当的电解质添加剂可以改变薄膜中的磷含量。电化学腐蚀测试结果表明，在含有柠檬酸盐（C6 H5 O 73 −）的电解液中制备的膜与所有其他电解液相比在化学和动力学上更稳定。Mott-Schottky分析结果表明，所有制备的薄膜都表现出n型半导体行为，并且在含有柠檬酸盐（C6 H5 O 73-）的电解液中形成的薄膜表现出最低的施主浓度和最负的平带电位，这有助于其在SBF溶液中的最高耐腐蚀性。盐雾加速腐蚀试验的结果与电化学和Mott-Schottky分析的结果一致。
The primary objective of the present work was to study the electronic and in vitro electrochemical properties of micro-arc oxidized titania films on Cp Ti, fabricated independently in various electrolyte solutions consisting of anions such as phosphate (PO43−), borate (B4O72−), citrate (C6H5O73−) and silicate (SiO32−). Further the role of anions on the structural, morphological and compositional properties of the fabricated films was studied. All the titania films were developed by micro-arc oxidation (MAO) technique for a fixed treatment time of 8min under constant current mode. The surface morphology, elemental distribution, composition and structural characteristics of the films were assessed by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The thermodynamic and kinetic corrosion properties of the films were studied under simulated body fluid (SBF) conditions (pH 7.4 and 37°C) by conducting chronopotentiometric and potentiodynamic polarization tests. Electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit modelling was carried out to analyse the frequency response and Mott–Schottky analysis was performed to study the semiconducting (electronic) properties of the films. Salt spray fog accelerated corrosion test was conducted for 168h as per ASTM B117 standard to corroborate the corrosion and semiconducting properties of the samples based on the visual examination. The XRD results showed that the transformation from the metastable anatase phase to the thermodynamically stable rutile phase and the crystalline growth of the respective phases were strongly influenced by the addition of anions. The SEM-EDS results demonstrated that the phosphorous (P) content in the films varied from 2.4at% to 5.0at% indicating that the amount of P in the films could be modified by adding an appropriate electrolyte additive. The electrochemical corrosion test results showed that the film fabricated in citrate (C6H5O73−) containing electrolyte is thermodynamically and kinetically more stable compared to that of all the others. The results of the Mott–Schottky analysis indicated that all the fabricated films showed an n-type semiconducting behaviour and the film developed in citrate (C6H5O73−) containing electrolyte exhibited the lowest donor concentration and the most negative flat band potential that contributed to its highest corrosion resistance in SBF solution. The results of the salt spray accelerated corrosion tests were in agreement with those obtained from the electrochemical and Mott–Schottky analysis.