Preparation Of Superhydrophobic Surface Of Tubing By Composite Electrodeposition

In the process of oil exploitation,the corrosion problem of tubing is becoming more and more serious.In industrial application,it's service life and application value are seriously restricted.In order to enhance the corrosion resistance of the tubing,it is necessary to surface treat the substrate without changing its main properties.Superhydrophobic surface with the properties of self-cleaning,reduce resistance,anti-icing,oil-water separation and high corrosion resistance is a new research direction in the field of corrosion protection.This paper combines the advantages of composite electrodeposition and superhydrophobic surface.With 304L stainless steel as the matrix,combined with the excellent properties of particles.Two kinds of superhydrophobic surfaces of 304L stainless steel were prepared by composite electrodeposition to construct micro nano dual rough structure on the substrate,which improved their comprehensive properties and made them widely used in industry.The specific research contents and corresponding conclusions of this paper include the following points:First of all,after consulting a large number of relevant materials and reading through the literature,in order to improve the adhesion between the substrate and the coating,with nickel plated base,in the pure nickel coating on the composite electrodeposition,try to test for many times.Finally,the main components of composite plating solution and the optimum range of composite electrodeposition process conditions were determined,in order to determine the optimum process parameters and single factor experiments.Taking Si C,Al₂O₃particles as the second phase.The effects of current density,different sizes of Si C particles,deposition time,addition of Al₂O₃particles,addition of Si C particles and bath temperature on the morphology and properties of Ni-Si C-Al₂O₃composite coating were investigated by single factor experiments.Through scanning electron microscope(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),hardness test,roughness test,contact angle test and coating performance analysis.It is the optimal process parameter for the preparation of superhydrophobic Ni-Si C-Al₂O₃composite coatings with high hardness,high contact angle and high corrosion resistance that the current density is 4 A/dm²,the deposition time is 60 min,the bath temperature is 60?,the Si C particle size is 40 nm,the addition amount of Si C in the bath is 2 g/L,and the addition amount of Al₂O₃in the bath is 10 g/L.Then,the enhanced second phase Si C particles in the composite bath are replaced with Mo S₂particles,and combined with the self-lubricating properties of Mo S₂particles,the more ideal superhydrophobic surface with low adhesion was prepared.The current density and the amount of Mo S₂in the bath which have the greatest influence on the performance of the coating were selected as the research objects:When the current density was 8 A/dm²,the superhydrophobic Ni-Mo S₂-Al₂O₃composite coating with hardness of547.1 HV and contact angle of 159.6°was prepared.However,with the increase of Mo S₂concentration,the hardness of the coating decreases sharply,and the hardness is as low as408.5 HV.At the same time,the contact angle of the composite coating is increased and enhance its self-cleaning property.Finally,the corrosion resistance experiments of two different superhydrophobic composite coatings and matrix materials were carried out.According to the Tafel polarization curve obtained by the electrochemical workstation:The self-corrosion potential of superhydrophobic Ni-Mo S₂-Al₂O₃composite coating is the most positive,and the corrosion current density is the least.The self-corrosion potential and corrosion current density are followed by super-hydrophobic Ni-Si C-Al₂O₃composite coating,and the self corrosion potential of substrate is the most negative and the corrosion current density is the largest.The corrosion resistance strength of the three samples was obtained by combining the corrosion morphology of the cross section:Superhydrophobic Ni-Mo S₂-Al₂O₃composite coating>superhydrophobic Ni-Si C-Al₂O₃composite coating>substrate.