| Metal corrosion causes serious harm to the lives and environment of contemporary people.Among various anti-corrosion technologies,coating protection is the simplest and most effective method.Epoxy resin coatings are widely used in the field of anti-corrosion because of their advantages such as high bonding strength,strong corrosion resistance and excellent mechanical properties.Nevertheless,the cured epoxy resin has some weaknesses including low shrinkage and high brittleness.Besides,its corrosion period is short.The application of functional inorganic nanofiller in epoxy resin coatings is one of the effective ways to enhance the anti-corrosion performance of coatings.Sepiolite?SEP?,as a new inorganic nanofiller,which has abundant reserves,excellent performance and good corrosion resistance.However,the hydrophilic surface of natural SEP has many impurities,which is not is not conducive to its application in epoxy resin coatings.Nano-titanium,as a spherical nanofiller,which has high strength,excellent corrosion resistance.However,it is easy to agglomerate in epoxy resin coating.Therefore,in order to reduce the production cost of EP coatings,improve the corrosion resistance of epoxy resin coatings,and improve the dispersion of fillers in EP coatings.Firstly,the organic sepiolite?OMSEP?and organic sepiolite/nano titanium?OMSEP/Ti?composites are successfully prepared in this paper,then the organic sepiolite?OMSEP?and organic sepiolite/nano-titanium powder?OMSEP/Ti?composites are added to the EP coating.The effect of the"synergy"of the two compounds on the corrosion resistance and anti-corrosion mechanism are investigated.The specific research contents of this paper are as follows:?1?Determination of the best process parameters during the modification of SEP.Testing methods such as X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FT-IR?,contact angle,scanning electron microscopy?SEM?and transmission Electron Microscopy?TEM?are used to characterize the changes of sepiolite material before and after modification.The results show that the optimal process for acid modification of SEP is:the concentration of dilute hydrochloric acid is2 mol/L,the reaction temperature is 80?,the reaction time is 12 h;The optimal process of modified SEP by silane coupling agent KH570 is as follows:The amount of coupling agent KH570 is 50%of the filler,the reaction temperature is 95?,and the reaction time is 4 h.After step-by-step modification of SEP,the contact angle of SEP changed from the initial 16°to 101°.?2?Preparation of OMSEP/EP coatings with different content and research on their anti-corrosive properties.The effect of different content of OMSEP filler on the comprehensive performance of pure EP coating is investigated.The results show that the comprehensive performance of pure EP coating could be significantly improved by the addition of OMSEP filler.And when the amount of OMSEP filler added is 3%,the adhesion level of OMSEP/EP coating is 1,the impact resistance is 52 kg.cm,the abrasion is only 0.01 g,and the impedance at low frequencies(|Z|0.01 Hz)is much higher than that of pure EP paint.In addition,the impedance value at low frequency region(|Z|0.01 Hz)of the 3%OMSEP/EP coating immersed for 120 h is about 109?.cm2,which is three orders of magnitude higher than the pure EP coating immersed for 6 h,showing the best Excellent corrosion resistance.?3?Preparation of omsep-ti composite material and its anticorrosion performance in epoxy resin coatings.and the composites are characterized and analyzed by X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FT-IR?,X-ray electron spectroscopy?XPS?and scanning electron microscopy?SEM?tests.The optimum composition ratio of OMSEP-Ti composites is investigated.The comprehensive performance and corrosion mechanism of OMSEP-Ti/EP coatings are studied.The results show that the optimal compounding ratio of OMSEP-Ti composite is 2:1.At this time,the impact resistance performance of the OMSEP-Ti/EP coating with composite ratio of 2:1 is increased by 75%compared with that of pure EP coating,and the abradability is increased by 83.3%.After 720 h of chemical resistance test,only slight corrosion appears on the surface of the OMSEP-Ti/EP coating;after 1500 h of salt spray resistance test,surface of the OMSEP-Ti/EP coating with a composite ratio of 2:1 is still intact.The anticorrosion mechanism of the composite coating was explored through the change of the propagation path of the corrosive medium in the coating.The successful grafting of the silane coupling agent and the"labyrinth effect"of inorganic nanomaterials jointly promoted the improvement of its corrosion resistance. |
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