The Properties And Preparation Of Zinc-rich Coatings From Sodium Silicate Solution Modified With The Organic Acid Salt

The zinc-rich coating from sodium silicate solution has excellent properties of anti-corrosion , durability , lower cost and low-VOC-emitting, but the application of the coating is limited by its poor water resistance, which affects the quality and property of the final film. The aim of this thesis is to solve the above problem and prepare high-performance zinc-rich coating from sodium silicate solution modified with the organic acid sal(t ammonium acetate,ammonium oxalate and ammonium citrate ) Through basic properties test , optical micrograpHy observation Fourie-transform spectr( FTIR)measurement ,steady and dynamic rheological experimentation and model fitting, the results indicate:through study of the modified zinc-rich coating ,we can find the basic property improvements,especially water-resistance,arrive at the aim of experiment; through the basic properties, gain the best formula.The optical micrograpHy observation demonstrates that the anti-corrosion property and configuration of the film becomes better according to the best formula. FTIR measurement proves that the reaction among sodium silicate , modificator and zinc pigment.The steady rheological experimentation shows that this coating belongs to shear-thinning fluid, the temperature sweep curves show that viscosity goes down with temperature rise.Kamal model can fit the curve of viscosity over time.The shear force increases as shear speed minishes.The dynamic rheological experimentation gained the angular frequency sweep curves( G'～ω,G"～ω),they show that the elastic moduli reduces along with the pH of organic acid salt raise, but at the beginning the viscous moduli rises with PH,then goes down,the relationship between the elastic and viscous moduli and angular frequency can be fitted by multinomial.