| Metal corrosion mainly refers to the metal itself is damaged by the role of thesurrounding environment. Every year the disaster accident caused by corrosion problemis not in the minority, it not only brings the serious economic losses, but also threatspeople’s personal safety. However, the traditional general anticorrosion technology hasits own defects, and expenses lots of resources. Therefore, to explore a kind ofenvironment-friendly new anticorrosion measures has become the key to solve theproblems.Photogenerated cathodic protection is that, under the light-on conditions, when thephoton energy is higher than that of the semiconductor band gap energy, semiconductorvalence band electrons will be excited to conduction band, and form the high activity ofphotogenerated electron hole pairs, generated electrons moving to the protected metalwhich has the low potential, and the semiconductor produce photopotential, so thepotential of the metal surface decreases. This potential negative shift is significantlylower than that of natural corrosion potential of metals, which plays the effect ofcathodic protection.TiO2is a kind of common photoelectric material, it owns the characteristics ofgood photocatalysis, photosensitization, and become a very promising material.However, due to the limit of TiO2property, especially the efficiency of solar energyconversion is low. In this paper, we will carry on modifying TiO2, to improve thephotoelectric conversion rate. Thus it can improve the photogenerated cathodicprotection performance, and own the better protection preformence of stainless steel.This article mainly contains the following aspects:(1) TiO2nanotubes are prepared by anodization method, according to the study ofthe variation potentials; it shows the best oxidation potential by observe thephotoelectric conversion performance and photogenerated cathodic protectionperformance.(2) Titanium dioxide as the substrate, CdSe is deposited on the TiO2nanotubearrays by cyclic voltammetry, it is observed the surface morphology and crystal phase of the composite characteristics through scanning electron microscopy (SEM), X raydiffraction (XRD) and other testing method, and to study the photoelectric conversionperformance and the property of304stainless steel cathodic protection through someelectrochemical methods, such as the open circuit potential (OCP), electrochemicalimpedance spectroscopy (EIS) and the tafel polarization curves. The electrochemicaltests show that open circuit potential of304stainless steel is decreased from-190mV to-500mV under the light-on, closed after the light, the electrode potential slowly rises toabout-250mV, that dark state material still could maintain the protective effect onstainless steel.(3) Titanium dioxide as the substrate, CdSe is deposited on the TiO2nanotubearrays by cyclic voltammetry, CdTe/TiO2composite which owns the best photoelectricconversion performance is obtained by changing the number of the deposition of theelectrolyte acidity. The results showed that, under visible light irradiation, cathodicprotection performance of CdTe/TiO2composite material is better significantly than thatof pure titanium dioxide, and when the light is off, it still can maintain the protection ofstainless steel;(4) Titanium dioxide as the substrate, ZnSe is deposited on the TiO2nanotubearrays by cyclic voltammetry. It is found the best photoelectric conversion performanceof CdTe/TiO2composite by changing the number of the deposition cycle circles.According to the electrochemical test, after the number of cycles reaches40laps, thecomposite material owns the best performance of the photoelectric conversion. Underthe visible light irradiation, the open circuit potential of304ss can be negative to-780mV.(5) Titanium dioxide as the substrate, MnSe/TiO2composite materials are preparedby SILAR. The electrochemical shows that the OCP of304ss coupled with MnSe/TiO2composite can be reduced to-730mV, so it achieves the protection effect of stainlesssteel. |
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