Studies On The Preparation And Properties Of The Biomimetic Superhydrophobic Surface On X90 Pipeline Steel

Superhydrophobic surface has attracted many researchers’ attention due to its wide application prospects in recent years.The application of superhydrophobic surface to the petroleum and petrochemical pipeline inner wall can increase the hydrophobicity of the water mixture on the pipeline wall,improving the transportation efficiency,reducing the production costs and saving energy.It is found that the appropriate surface microstructure morphology and low surface energy are two necessary conditions for achieving superhydrophobicity on material surfaces.In this dissertation,a metal coating was obtained on the X90 pipeline steel substrate by electrodeposition method,which can protect the substrate.And then,a microstructure film grew in-situ on the electrodeposited metal coating via hydrothermal reaction or chemical oxidation.Finally,superhydrophobic surfaces with three different surface morphologies were obtained after low-energy modification.The fabrication processing parameters of three superhydrophobic surfaces were optimized.The reason for the superhydrophobicity of the prepared surface was analyzed by establishing microstructure wetting theory models.The impact dynamic behaviors of water droplets on these three superhydrophobic surfaces were studied.The stability and application prospect of these three superhydrophobic surfaces were evaluated systematically.The results are as follows:A superhydrophobic zinc coating with hexagonal prism ZnO film was prepared on the X90 pipeline steel substrate by the composite methods of electrodeposition of zinc coating,hydrothermal reaction for in-situ growth of ZnO and low-energy modification.By controlling the processing parameters,the hexagonal prism ZnO microstructure,almost perpendicular to the surface,was obtained.After low-energy modification,this surface achi-eved superhydrophobicity with the water contact angle of 157.59° and the rolling angle of 6°.Based on the Wenzel and Cassie two wetting theory models,three-dimensional hexagonal prism microstructure wetting theory model was established to reveal the mechanism of forming the stable Cassie state when water droplets were in contact with the superhydrophobic zinc coating surface with the ZnO film.The superhydrophobic copper coating with flower-like CuO film was prepared on the X90 pipeline steel substrate by using electrodeposition of copper coating,chemical oxidation for in-situ growth of CuO film and low-energy modification.The hierarchical flower-like CuO microstructure morphology,just like the upper surface morphology of the lotus leaf,was obtained by the single variable method.After low-energy modification,the water contact angle was 160.69°,and the rolling angle was about 3°,achieving superhydrophobicity.The stable Cassie wetting state between water droplets and this superhydrophobic surface was proved by a simple approximate calculation.Cu-Zn alloy has good anti-scale property.Fabricating the superhydrophobic copper-zinc alloy coating on the X90 pipeline steel substrate can reduce the scaling phenomenon of water mixture on the pipeline wall.The superhydrophobic copper-zinc alloy coating with dandelion-like CuO film was prepared on the X90 pipeline steel substrate by electrodeposition of copper-zinc coating,chemical oxidation for the in-situ growth of CuO film and low-energy modification.By adjusting the processing parameters to obtain hierarchical dandelion-like microstructure surface,after low-energy modification,the water contact angle on this surface was 157.94°,and the rolling angle was about 3°.Based on Wenzel and Cassie two classical wetting theoretical models of a rough surface,the ideal double-scale theoretical model composed of spherical and pillared microstructure was established.It was theoretically proved that the wetting state between the water droplets and this superhydrophobic surface was the stable Cassie-Cassie wetting state.Dynamic behaviors of water droplets impacting on the superhydrophobic zinc coating surface with hexagonal prismatic ZnO film,the superhydrophobic copper coating surface with flower-like CuO film and the superhydrophobic copper-zinc alloy coating surface withdandelion-like CuO film were studied.These results further characterized that the superhydrophobicity of above three superhydrophobic surfaces was stable.There were three conditions,including regular rebounding,jetting and splashing phenomenon,after water droplets impacting on the superhydrophobic surfaces with different velocities,without water attaching or spreading on the sample surfaces.The reason for these superhydrophobic surfaces to resist the impacting water droplets was explained from the perspective of wetting and anti-wetting pressure.In addition,the relationship between the contact time,contact diameter,retraction rate,restitution coefficient and the impact velocity,and Weber number was analyzed when the water droplets impacted on these superhydrophobic surfaces.The hydrophobic and mechanical stabilities of these three superhydrophobic surfaces with different surface morphologies were studied under different conditions and environments.The anti-corrosion property,self-cleaning property,oleophobicity and anti-scale property of these superhydrophobic surfaces were studied and evaluated.It was found that these three superhydrophobic surfaces had good time stability,anti-heat stability and certain corrosion resistance for acid and alkali.After tape stripping,all surfaces had good hydrophobic stability.All superhydrophobic surfaces had better self-cleaning property,and the reason for self-cleaning property was explained in the perspective of force,showing the relationship between self-cleaning ability and the size of contaminant particles.The oleophobicity of the superhydrophobic copper and copper-zinc alloy coating surfaces were better than the superhydrophobic zinc coating surface.The superhydrophobic copper coating surface had better hydrophobic stability after ultrasonic shock and the best anti-corrosion property.The superhydrophobic zinc coating had better abrasion resistance.The superhydrophobic copper-zinc coating surface had a certain anti-scale property.