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Modeling barrier film growth and dissolution on titanium based on EIS, XPS and photocurrent data
Electrochimica Acta ( IF 5.5 ) Pub Date : 2020-04-01 , DOI: 10.1016/j.electacta.2020.136137
Martin Bojinov , Iva Betova , Vasil Karastoyanov

The relatively large number of adjustable parameters often precludes the unambiguous interpretation of electrochemical impedance spectroscopic (EIS) measurements in terms of a unique kinetic model. An approach to overcome this ambiguity by parameterization of a model of barrier film growth and dissolution on Ti in fluoride-containing solutions using a combination of in-situ EIS and photocurrent measurements, combined with ex-situ characterization of the oxides by X-ray photoelectron spectroscopy (XPS) is presented. The kinetic model features barrier layer growth via inward transport of oxygen and fluoride mediated by anion vacancies. Dissolution of titanium through the oxide proceeds via two parallel pathways mediated by interstitial cations and cation vacancies, respectively. Outer layer growth is assumed to be limited by the transport of interstitial cations through the barrier layer. Ways to extract information on the rate-limiting steps of the process of passive film formation, growth and restructuring are described and the significance of the obtained parameters for the kinetics of barrier film growth and dissolution is outlined.



中文翻译:

基于EIS,XPS和光电流数据,模拟在钛上阻挡膜的生长和溶解

相对大量的可调整参数通常排除了根据唯一的动力学模型对电化学阻抗谱(EIS)测量的明确解释。通过结合使用原位EIS和光电流测量以及X射线光电子对氧化物的原位表征,结合参数化阻挡膜生长和在含氟溶液中的Ti在Ti上的溶解模型,克服了这种歧义光谱(XPS)被提出。动力学模型的特征是通过阴离子空位介导的氧气和氟化物的向内传输,使阻挡层生长。钛通过氧化物的溶解分别通过间隙阳离子和阳离子空位介导的两个平行途径进行。假定外层生长受间隙阳离子穿过阻挡层的传输的限制。描述了提取有关被动膜形成,生长和重组过程的限速步骤的信息的方法,并概述了所获得的参数对阻隔膜生长和溶解动力学的意义。

更新日期:2020-04-01
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