| Failure of railway is mainly caused by combinative effect of stress damage and atmospheric corrosion. Humid air, rain, polluted air and difference in temperature are considered to induce electro-chemical corrosion. The corrosion of railway takes place more easily when stress frequently acts on it. As a result, distortion and cracks occurred to accelerate the railway’s corrosion. At the same time, the current from the train’s signal circuit are partly leaked as the insulation between the railway and the earth is limited which would worsen the corrosion of the railway. And all these factors synthesize the mechanism of railway’s corrosion.With regard to a worse air condition results from the overwhelming popularity of vehicles in the future, all the steel products’corrosion could be aggravated. Thus, the atmospheric corrosion will become a key factor to shorten the railway service life which immediately asks for efficient and costly maintenance as soon as possible. Organic-inorganic composite coating turns out to be a promising anti-corrosion material as it combines the outstanding properties of organic and inorganic including low cost, simple technology, environmentally friendly and designable.In this work, the corrosion factors has been studied according to the damages caused by corrosion from DaoYaoShan Tunnel, ZhuZhou north station and etc., all affiliated to Guangzhou Railway (Group) company. TEOS-KH570composite coating was prepared by sol-gel to discuss its property and possibility of application.Firstly, the corrosion mechanism has been studied by calculation of corrosion rates, detection of hardness, X-ray diffraction analysis and morphology image observation by SEM respectively. The result indicated that there are mainly two forms of railway corrosion. One is the uniform corrosion of faces and waists as well as fix parts. The other one is the regional corrosion results from mechanical and fatigue damages. The former shares the same atmospheric corrosion mechanism with other steel products. The latter has a more complicated one that is related with environmental factors (including damp air, temperature and its range, rainfall, atmospheric pollution and stray current) and the mechanical and fatigue damages of the rail.Secondly, the property of the composite coating including anti-corrosive, electro-chemical, chemistry components, structure and morphology has been tested by salt spray, polarized curves, infrared spectrum, energy spectrum and SEM. The result showed that1) The anti-corrosion property of the metal sample has been improved by one to two magnitude since the polarized current of the coated ones are reduced compared with those of the naked ones.2) The composite coating is anti-corrosive when prepared in acid environment with maximum at pH3～4.3) The property of anti-corrosion performs best when the ratio of TEOS:KH570is4.4) The anti-corrosion is decreasing while the proportion of water is increasing from1to5. |
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