Electrochemical Evaluation of TiO2, Cerium and Iron TiO2 Based Nanofibers Coatings in Copper and Copper Alloys Substrates

Nanofibers have very well known applications in several fields like medicine, textile industry and energy systems. They can be produced by different techniques including electrospinning. In this work, a process for obtaining TiO₂ cerium and iron TiO₂ nanofibers with a mesoporous structure was performed in order to produce coatings and evaluate their properties. The formation of porous structures using titania, mixed titania/ceria and mixed titania/iron oxides precursor solutions was achieved with a polymer gel templating technique. The nanofibers were prepared with a sol–gel solution containing a mixture of poly (vinyl pyrrolidone) [PVP, Mw 1 300 000], titanium tetraisopropoxide [Ti(O-i-Pr)₄], a triblock copolymer Pluronic F127, cerium(III) nitrate hexahydrate [Ce(NO₃)₃∙6H₂O] and iron oxides using the electrospinning technique. The synthesis process was carried out afterward to promote the crystallization and phase transformation to anatase, as well as to remove the polymer via calcination in air at 500 °C. Scanning electron microscopy (SEM) revealed the average diameters of the resulting nanofibers were in the 70 nm to 200 nm range, depending on the preparation conditions. The aim of this work was to evaluate the electrochemical behavior of TiO₂, cerium and iron TiO₂ based nanofibers coatings applied to copper and copper alloys surfaces. In order to achieve this goal, an experimental procedure was designed which allowed to simulate the degradation of the coatings in corrosive environments. The techniques used included electrochemical noise measurement, electrochemical impedance spectroscopy and potentiodynamic polarization.