| Carbon steel is widely used in engineering machinery and construction projects and various field because of its good machinability and low price. But it must be given appropriate suface treatment so as to prolong its working life on account of the poor corrosion resistance of carbon steel itself. Amang the traditional treatment, chromizing and phosphating present good properties of unticorrosion. However, chromizing and phosphating will be banned in the near future due to their uphold hazard to environment and carcinogenic to humans. So, it has truly significant and have been popular in home and abroad to study on the new suface treatment which have properties of efficient performance of unticorrosion and environment-friendly and low price.In order to prepare a kind of hybrid membrane, which was taken silane as the backbone,cerous nitrate and tetraethyl orthosilicate as additives. In this article, the optimum technics of the film prepared with bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTESPT,oil-base silane) and vinyltrimethoxysilane (VTOS,water-base silane)on the carbon steel surface was studied first. The formation and surface structure of the film were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results indicate that two kinds of silane can form uniform and compact film on the Q235 carbon steel surface. The corrosion behaviour of the two silane films in the artificial simulated seawater was evaluated by potential dynamic polarization and electrochemical impedance spectroscopy (EIS). The results indicate, twe silane films both have better protect for carbon steel in short time. BTESPT film has better effect than VTOS film. As other organic films, the deficiency of the single silane film is that they haven't corrosion resisting property, they can't play the role of anti-corrosion for long term.The strcture of silane film on the carbon steel surface is net type which provide some packing space for nano inorgannic particles. That is to say the hybrid membrane can be much compact and integrated through silane coorprate with inorgannic or oxide nano particles. In addition, the film will take on a function of self-repairing by the addition of variant valene metal. Cerium is a kind of variant valene metal. cerium nitrate can soluble both in water and ethanol absolute, it is asepsis and low-priced. Furthermore, tetraethyl orthosilicate (TEOS) has good compatibility with silane. These provide us a well platform for further experiment.Aim at the above-mentioned shortage and superiority, we employ vinyltrimetho- xysilane (VTOS ) and bis-(γ-triethoxysilylpropyl)-tetrasulfide(BTESPT) respectively coorperated with ceric ammonium nitrate. The results of potential dynamic polariza- tion and electrochemical impedance spectroscopy (EIS) show the nano particles in the hybrid membrane prepared with VTOS coorperated ceric ammonium nitrate is about 90 nm; the nano particles in the hybrid membrane prepared with BTESPT cerium nitrate is about 30nm. EDS show cerium is an element of the film-foming. The results of both potential dynamic polarization and electrochemical impedance spectro- scopy (EIS) indicate the effect unticorrosion for carbon of the hybrid membrane is better than single silane film,but not great obvious.Compared with VTOS, BTESPT is better fit for carbon systerm.In order to improve the antiseptic property of the hybrid membrane, the technics of hybrid membrane prepared with BTESPT/ Cerous nitrate/ TEOS mixing together through one step is initially explored. The outcome of potential dynamic polarization combined with EIS and 3% copper sulphate spot testing show, the addition of the TEOS indeed improve the protect property for carbon steel. |
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