Research And Application On The Properties Of Nano Modified Cathodic Electrophoretic Paint

It has been studied that a new type nano modified cathodic electrophoretic coating with corrosion resistance and weather resistance is used to paint Q235B carbon steel.Nano particles(rutile nano TiO2, anatase nano TiO2and nano SiO2)have been modified by dispersant and ultrasonic wave combining method. The suitable dispersant and best ultrasonic pretreatment conditions of nano particles have been determined by sedimentation and spectrophotometry. The dispersant of rutile nano TiO2is KH-151and content of dispersant is3%; ultrasonic pretreatment time is50min, temperature is35℃, power is150W. The dispersant of anatase nano TiO2and content of dispersant is TEA:SDS=2:1(TEA and SDS are20%and10%of anatase nano TiO2); ultrasonic pretreatment time is20min, temperature is35℃, power is145W. The dispersant of nano SiO2and content of dispersant is KH-570:SHMP=1:5(KH-570and SHMP are1%and5%of nano SiO2); ultrasonic pretreatment time is30min, temperature is35℃, power is180W. The surface topography and structure of unmodified and modified nano particles have shown by SEM and XRD that modified nano particles are better than unmodified particles.The modified nano particles are dispersed to cathode electrophoretic paint. Nano modified cathode electrophoretic paint is prepared. The electrophoretic coating process of nano modified cathodic electrophoretic paint is investigated. The best coating process of nano modified cathodic electrophoretic paint is determined. Voltage:110V, solid contents:17%to19%, temperature:29±1℃, time:120s, baking:170℃×20min. The normal properties and salt-water resistance of paint film are tested. The result has shown adhesion, impact strength and salt-water resistance of film is improved obviously when content of rutile nano TiO2is2.5%; hardness, impact strength and salt-water resistance of film is improved obviously when content of nano SiO2is2%; adhesion, hardness, impact strength and salt-water resistance of film is improved obviously when content of rutile nano TiO2and nano SiO2is2.5%. Then acid and alkaline resistance properties, salt spray resistance, weather resistance and surface topography of paint film is evaluated. The result has shown acid and alkaline resistance, salt spray resistance, weather resistance of film is improved obviously when content of rutile nano TiO2and nano SiO2is2.5%.