Effect Of Silane Pretreatment And PAI Content On The Corrosion Resistance Of PTFE Non-stick Coating And Its Mechanism

Polytetrafluoroethylene(PTFE)has attracted wide attention due to its excellent non-stick properties,heat resistance,self-lubrication and corrosion resistance.But the biggest difficulty of PTFE is poor adhesion and low dispersion in the matrix,so it is difficult to firmly bond with the metal matrix in the process of preparing the coating.In order to improve the adhesion of PTFE and the corrosion resistance of the coating,this article discussed the influence of PAI content on the corrosion resistance of coatings,and studied the effect of silane pretreatment on the coating.The effect of bonding strength and corrosion resistance,as well as the effect of adding GO and f GO to the coating performance.The coating performance PAI content,the pretreatment of the silane film and the relationship between processing and are functional additive content are systematically analyzed.First,the article studies the effect of different content of PAI on the performance of coating.The results of the electrochemical corrosion test show that with the increase of the PTFE content,the corrosion current density of the coating first decreases and then increases,and the corrosion current density of the 15 wt.%PAI coating decreases to 1/4 of the 10 wt.%PAI coating and 1/3 of the corrosion current density of the 20 wt.%PAI coating.The impedance modulus at the lowest frequency of the coating(f_min=0.01 Hz)first increases and then decreases.The impedance modulus of the 15 wt.%PAI coating is an order of magnitude higher than the impedance modulus of 10 wt.%PAI coating and 20 wt.%PAI coating.This shows that the content of PTFE within a certain range has an optimal effect on the corrosion resistance of the coating.This is because as the content of PTFE increases,the internal structure of the coating becomes denser,which can effectively block the penetration of corrosive media.When the PTFE is too much,agglomeration occurs inside the coating,which reduces the surface quality of the coating.,resulting in reduced corrosion resistance of the coating.Secondly,silane pretreatment was performed on the metal substrate to study the effect of silane pretreatment on the performance of the coating.The scratch test results show that the bonding strength of the silane pretreatment coating and the substrate is 1.3 times that of the coating and the substrate without the silane pretreatment.This is due to the dehydration condensation reaction between silanol of the silane film and the hydroxyl group in the metal matrix.And then the R base of the silane film and the organic components in the coating form chemical bonds or interpenetrate each other through van der Waals forces,thereby enhancing the bonding strength of the coating-substrate.From the salt spray test results,it can be seen that after the 12-hour salt spray test,the corrosion of the scratches of the silane pretreatment coating is lighter.This is because during the formation of the silane film on the substrate surface,the combination of the silanol and the combination of and the combination of silanol and the hydroxyl group of the metal matrix together form a dense silane film.This silane film becomes a new barrier and improves the corrosion resistance of the coating.Then,GO is added as a functional additive to the silane film,and the effect of GO/BTESPT silane film on the performance of the coating is studied.It can be seen from the salt spray test results that after a 12-hour salt spray test,the corrosion degree of the silane pretreatment coating with GO added is lighter than that of the single silane pretreatment coating.According to the electrochemical corrosion test results,the corrosion current density of the silane pretreatment coating with 1.5 wt.%GO is two orders of magnitude lower than that of the single silane pretreatment coating,and the silane pretreatment coating with 1.5 wt.%GO The impedance modulus at the lowest frequency is an order of magnitude higher than that of a single silane film pretreatment coating.This is because a single silane film has defects such as pores,which provide a path for the diffusion of corrosive media,and the addition of GO can improve its defects as much as possible,and due to the chemical inertness of GO itself,it can further improve the corrosion resistance of the coating,but GO,as a carbon nanomaterial,will produce clusters when its content is high,which will affect the performance of the coating.Finally,the GO is functionalized to obtain f GO,and add f GO to the silane film as a functional additive to study how f GO/BTESPT silane film effect the PTFE non-stick coating,and establish the impact of performance,and establish the corrosion resistance mechanism of f GO/BTESPT modified silane film.The salt spray test results show that,compared with the coating with GO,the coating with f GO has a lighter surface morphology corrosion after the12-hour salt spray test.It can be seen from the results of electrochemical corrosion tests that the corrosion current density of the f GO coating is lower than that of the GO coating.The impedance mode of the coating with f GO at the lowest frequency is the amount of the impedance mode of the coating with f GO is about 2 times that of the coating with GO added.This is because GO can be better dispersed in the silane film after functionalized treatment,and then connects with each other.It can be better improve the defects of the silence film,develop a larger impact of GO and improve the defects of the silane film,and also more.Give full play to the role of GO and improve the corrosion resistance of the coating.