A Study On Corrossion Resisting Property Of Heavy Anti-Corrosive Coatings

Recently,with the strengthen of consciousness about energy conservation and environmental protection,long-term corrosion resistance coating was developed promptly and used widely. Accordingly,study about corrosion resisting property of coatings was regarded,the relationship between water vapor transmission rate and corrosion electrochemical parameter of coating-metal interface was investigated tentatively.The protective of epoxy-based heavy-organic coatings attached to a metal substrate was studied using water vapor transmission rate technique of organic coatings and electrochemical impedance spectroscopy (EIS) technique in this paper. The effects of film thickness,soak period,flakes content and ageing factor were investigated. The results obtained indicate that film thickness dramatically affects the rate of corrosion of the metallic substrate,an increase in pore resistance of coatings was observed on increasing the film thickness,while double layer capacity and water vapor transmission rate was reduced. With the increasing of soak period,pore resistance of organic coatings was reduced,while double layer capacity was increased,corrosion resisting property of coatings was reduced. While flakes content was below 30%,resistance penetration of coatings was increased with the increasing of flakes content,flakes content was above 35%,resistance penetration of coatings was reduced,flakes content was 30%,good corrosion resisting property was observed. During immersion of acrylic acid coating,intermediate product was observed.Corrosion resisting property of acrylic acid coating was reduced greatly when exposed to 340nm UV-light about 300h,EDAX indicate that C-O-C of high polymer was degraded because UV-light was absorbed by acrylic acid resin,which induced increasing of pinholes and air bubble of coating,severely influenced corrosion resisting property of coatings.Corrosion resisting property of coatings can be evaluated by EIS,water vaportransmission rate technique and salt spray test. Water vapor transmission rate organic coatings and three stages of medium permeation can be quantitatively tested by water vapor transmission rate and curve of soakage to time,unfortunately,corrosion of coating-metal interface can not be specifically described by this method. However,this corrosion procedure can be qualitatively and continuously determined by Electrochemical impedance spectroscopy. Salt spray test only describes qualitatively corrosion resisting property of coatings by phenomena. In this way,procedure of corrosion resisting property of organic coatings can be comprehensively evaluated by combining the three ways,transition interval of coating early corroded can be predicted,influence factors of water vapor transmission rate of organic coatings and transition interval can be studied.Author:Lixia Yang (Material Science)Directed by:prof. An Lin,prof. Sanping Zhang...