Study On The Mechanism Of Bonding Surface Of Chrome Plate To Organic Film

Film-coated iron has the characteristics of excellent corrosion resistance,rust-proof performance,excellent taste retention,etc.,and its manufacturing process has low energy consumption,green environmental protection and other advantages.Therefore,film-coated iron is used in DRD stamped cans,DI cups Film cans,shaped cans,easy-to-open lids,and easy-to-tear lids are widely used in packaging materials.However,in the application process of coated iron,with the increase of the exposure time,the protection performance decreases,and the surface film is easy to fall off,which is largely due to the bonding force between the chrome plate and the film.Therefore,it is of great theoretical significance and practical application value to study the influencing factors of the bonding force between the surface of the chrome plated and the organic film.In this thesis,the effects of different surface characteristics and baking temperature on the bonding ability of the surface of chrome-plated plates to organic films were studied.The electrochemical resistance,porosity test,and contact angle test were used to analyze the corrosion resistance,density,and surface energy of the surface of chrome-plated plates.Influence of the ability to combine with organic films and optimize the plating current density.X-ray photoelectron spectroscopy(XPS)was used to analyze the effect of the coating composition on the bonding force.The change of the coating composition on the surface of the chrome plate before and after baking was studied.The influence of the surface morphology of the chrome plate on the surface bonding force was determined by scanning electron microscopy(SEM),Draw the following main conclusions:(1)With the increase of the plating current density,the corrosion resistance of the chrome plate under the NH4F system and the H2SiF6 system increases first and then decreases,the porosity decreases first and then increases,and the surface energy increases first and then decreases.When the plating current density is 10 A·dm-2,the chrome-plated plate has good corrosion resistance and denseness,and the surface energy is 37.39 × 10-3 N·M-1 and 37.34×10-3 N·m-1.At this time,the number of thermal vibrations of the chrome-plated plate under the NH4F system is 53 times,and the number of thermal vibrations of the chrome-plated plate under the H2SiF6 system is 113 times.Corrosion is gradually increasing,the porosity is gradually increasing,and the surface energy is gradually decreasing.When the plating current density is 5 A·dm-2,the corrosion resistance and density are good,and the surface energy is the largest.At this time,chromium plating The number of thermal vibrations of the board was 92,and the binding force reached the best.(2)The Cr(OH)3,Cr2O3,Cr,H2O components are present on the surface structure of the chrome plating plates of the three plating solution systems.The plating solution system has a significant effect on the composition and content of the surface structure of the chrome plate.For the NH4F system,the content of Cr(OH)3 in the surface coating of the chrome plate is 33.94%,and the proportion of H2O is 25.79%;for the H2SiF6 system,the content of Cr(OH)3 in the surface coating of the chrome plate is 49.28%and H2O is 18.74%;For the Na2SiF6 system,the content of Cr(OH)3 in the surface coating of the chrome-plated plate accounts for 38.16%and H2O accounts for 21.63%.H2O in the coating is not good for the bonding force on its surface,and Cr(OH)3 is good for the bonding of chrome plated and organic film.Therefore,the bonding strength of the chrome-plated plate of the H2SiF6 system is good,and the number of thermal vibrations is 113 times.(3)Bake at 100℃,200℃,300℃,400℃,and 500℃ for 15 minutes.The wetted area on the surface of the chrome plate increases first and then decreases.At a baking temperature of 300℃,the wetted areas of five chrome-plated plates were 12.08 cm2·g-1,12.90 cm2·g-1,13.34 cm2·g-1,10.07 cm2·g-1,10.19 cm2·g-1.Under the conditions of 300℃,heating time of 0 min,15 min,30 min,and 60 min,the wetted areas of chrome-plated plates are not much different.After baking for 15 minutes,the content of Cr(OH)3 in the coating decreased,the content of Cr2O3 increased,and the content of H2O decreased.(4)The baking process has a significant effect on the ability of the surface of the chrome plated to combine with the organic film.With the increase of the baking temperature,Cr(OH)3 on the surface of the chrome-plated plate is transformed into Cr2O3,so that the content of Cr(OH)3 is reduced,resulting in a poor bonding ability between the chrome-plated plate and the organic film.