Corrosion Behavior Of Tinplate/Coating System Under Different Tensile Strains

Tinplate has a very wide range of applications in the food(beverage)packaging ranging from cans to functional beverages.However the tinplate are always deformed due to the external forces during the production,packaging,storage and transportation,which will affect its anti-corrosion performance.In this paper,the tensile deformation of the tinplate cans during storage and transportation and the corrosion process of tinplate cans under tensile deformation are simulated.The tinplate/coated tinplate was processed into a sample of a certain size,and the tinplate and the coated tin plate were processed by a tensile tester.The corrosion behavior of the tinplate and the coated tinplate under different deformation amounts in 0.1mol / L sodium chloride solution and 0.1mol/L citric acid solution were studied.The electrochemical impedance spectroscopy(EIS)of corrosion system was measured by Autolab 302 electrochemical station and then fitted and analyzed by Zsimpwin.VHX three-dimensional microscope and SEM were used to observe and analyze the surface morphology of the corrosion process.The content of the elements in the electrolyte was measured and analyzed by inductively coupled plasma spectrometer(ICP)In 0.1mol/L sodium chloride solution,the damage of the tin layer becomes more serious with the increase of deformation.The substrate corrosion is more serious because of sodium chloride solution along its defects,The more deformation of coated tinplate,The more serious the corrosion of the surface organic coating in the solution,with the time going,the solution continues to corrodes the tin layer until the complete failure of the matrix.In the 0.1mol/L citric acid solution,the more deformation of the tinplate,the greater the chance of contact between the matrix iron and the citric acid solution,and the severity of the corrosion is positive correlation with the deformation.For the coated tinplate,The corrosion process in the acid solution is divided into four stages,along the surface of the coated tinplate,the solution corrodes the organic coating until failure;then corrodes the tin layer until failure;the accumulation of the tinplate corrosion products isolate the matrix iron and solution,meanwhile slow down the corrosion rate;The matrix iron is exposed to solution and corroded until complete failure.