Preparation And Properties Of Nano ATO Antistatic Anticorrosive Coatings

Antimony-doped tin oxide(ATO)is widely used in antistatic,transparent thermal insulation and catalysis fields.In this paper,the preparation methods of ATO nano-powder and water-based slurry were studied.The properties of ATO nanoparticles were characterized by TEM,XRD,laser particle size analyzer and zeta potentiometer.Then the anticorrosive properties of ATO nano-powders were studied.The main contents are as follows:(1)Using SnCl4·5H2Oand SbCl3 as raw materials,ammonium bicarbonate as neutralizer,acetic acid as cosolvent and ethanol as reaction medium,ATO powder was prepared by solid-liquid heterogeneous coprecipitation method.The effects of reaction medium,acetic acid content,antimony content and calcination temperature on nano-powder were discussed.The experimental results show that the solid-liquid heterogeneous coprecipitation reaction takes ethanol as the reaction medium,and its own properties eliminate the hydrogen bond between the precipitated crystals of hydroxide precipitation,and facilitate the precipitation of crystals,which fundamentally slows the hard agglomeration between nanoparticles.When the additive amount of acetic acid is about 3.0%,the ATO nano-powders with uniform particle size,small particle size and less agglomeration can be obtained.When the mass ratio of Sb2O3 to SnO2 is 12%(the antimony content is 11%),the resistivity and primary particle size of ATO nanoparticles decrease to the minimum,which are 1.1?·cm and 6.1nm,respectively.With the increase of calcination temperature,the grain size of nano-particles decreased first and then increased.At 550 ?,the grain size also reached the minimum value of 5.6nm.The characterization results show that the ATO nano-powders prepared by solid-liquid heterogeneous coprecipitation reaction have tetragonal rutile structure,uniform shape and spherical shape,the primary particle size is 5?8nm,and the specific surface area is about 85.00m2· g-1,Resistivity is 1.O?·cm.(2)Using self-made nano-ATO powder as raw material and water as dispersion medium,the ATO nano-slurry was prepared by high-speed sand mill dispersion method by selecting suitable dispersant.The effects of three different dispersants,dispersant concentration,pH value,grinding time and centrifugal speed on the stability of the slurry were investigated.The properties of the ATO slurry prepared under the optimum conditions were characterized.The results showed that the optimum technological conditions were as follows:the pH of the slurry was 7.5,the grinding time was 2h,the optimum dosage of KOH,triethanolamine and Polyaniline were 2%,5%and 30%,respectively,and the centrifugal speed was 8000r/min.The ATO nano-size prepared by this method has the characteristics of uniform dispersion and stability.Its zeta potential is less than-40mv and its average particle size is less than 100nm.(3)The formulation of waterborne epoxy resin coating was optimized by orthogonal experiment design.The ratio and curing time of waterborne epoxy resin to curing agent were discussed.Effect of curing temperature and coupling agent content on mechanical properties of waterborne epoxy resin coating.The optimum technological conditions are as follows:the ratio of waterborne epoxy resin to curing agent is 1.5:1,the curing temperature is 40 0C,the amount of coupling agent is 2%,and the curing time is 10h.(4)Using waterborne epoxy resin as film-forming agent and water-borne nano-ATO slurry as antistatic and antistatic functional additive,nano-ATO antistatic anticorrosive coating was prepared by dispersion.The surface resistance and electrochemical impedance of nano-ATO antistatic anticorrosive coating were measured by measuring its surface resistance and electrochemical impedance.The effects of nano-ATO on the antistatic and anticorrosive properties of the coatings were discussed.The results showed that the surface resistance and corrosion resistance of the coating were improved with the addition of ATO.Compared with epoxy varnish,the surface impedance and corrosion resistance of the coating increased with the addition of ATO.For the composite coating containing ATO,the anticorrosion property of the coating increases first and then weakens with the increase of ATO content,and the coating containing 30%ATO exhibits the best anticorrosion property.The addition of Polyaniline as dispersant also improves the corrosion resistance of the coating.The surface resistance of the coating decreases with the addition of ATO,and when the solid content of ATO reaches 50%,the surface resistance of the coating decreases to about 107?.