Preparation And Properties Of Superhydrophobic Coating And Plating On Carbon Steel Surface

Metal corrosion can cause huge economic losses and loss of life and property every year,so the research on metal corrosion protection is of great significance.The superhydrophobic surface is widely concerned because of its unique structure,which can prevent the contact between corrosive liquid and matrix and effectively reduce the occurrence of metal corrosion.In order to improve the corrosion resistance of Q235 carbon steel,this paper successfully prepared superhydrophobic surface on carbon steel by different methods,and explored its hydrophobicity and corrosion resistance.This paper is mainly divided into the three parts:1.The superhydrophobic PDMS-TiO₂ composite coating was successfully prepared on the surface of carbon steel by simple,rapid and low-cost sol-gel combined with drop coating method.Firstly,TiO₂ was modified with n-octyltriethoxysilane,and then the modified TiO₂was combined with PDMS,which was coated on carbon steel to obtain superhydrophobic PDMS-TiO₂ composite coating.Its hydrophobicity and corrosion resistance were studied by contact angle measurement,electrochemical impedance spectroscopy and polarization curve measurement.The results show that the contact angle of the superhydrophobic composite coating is 153.49°,which has a certain improvement on the corrosion resistance of carbon steel.2.Taking watt nickel plating solution and nano-TiO₂ as composite electroplating solution,a micro-nano roughness structure is constructed on carbon steel by constant current deposition,and then the superhydrophobic surface is obtained by modifying with low surface energy substance.The influences of different current densities,the concentrations of TiO₂,the concentrations of low surface energy substance and plating times were investigated.The results showed that the superhydrophobic composite coating owned the best performance when current density was 50 mA/cm²,the concentration TiO₂ was 25 g/L,concentration of stearic acid is 1%,and the plating time was 30 min.Under this condition,the contact angle of the superhydrophobic composite coating was 160.99°,showing good superhydrophobic,self-cleaning property and abrasion resistance.The corrosion resistance of the superhydrophobic composite coating was investigated by electrochemical impedance spectroscopy and polarization curve measurement.The results showed that the superhydrophobic composite coating has excellent corrosion resistance.3.The electrolyte at the optimal concentration above was selected as pulse electroplating solution,and the superhydrophobic anti-corrosion surface was prepared on carbon steel by pulse electrodeposition and low surface energy modification.The effects of different pulse average current densities,pulse times,pulse duty cycles,and pulse frequencies were explored.The results showed that the superhydrophobic composite coating owned the best performance when the average current density is 30 mA/cm²,pulse plating time is 10 min,pulse duty cycle is 50%,and the pulse frequency is 10 Hz.Under this condition,the contact angle of the superhydrophobic composite coating was 156.99°.The corrosion resistance was investigated by electrochemical impedance spectroscopy,polarization curve and immersion experiment.The results showed that after 90 days of immersion in 3.5wt.%NaCl solution,the impedance value of the superhydrophobic composite coating was still high,the protection efficiency was as high as 99.59%,and it has long-term anti-corrosion performance.