Characterization Of Hydrophobic Mechanism Wetting On Rough Surface And Fabrication Of Hydrophobic Surfaces On H62Brass

A conclusion that integration of multi-scale limited liquid-solid interfaces increasing hydrophobic of lotus’like rough surface was produced. It based on the theory of limited liquid-solid interface. Conditions of hydrophobic wetting on single rough surface and micro-nano rough surface were studied respectively. The relation between air-gap theoretical critical radius of micro-nano rough surface and the property of solid and liquid was calculated. The results show that drop contact angle could keeps ble hydrophobic state wetting on solid surface when rough surface air-gap radius less than theoretical critical radius named rc Moreover, hysteretic could be reduced by minimizing liquid-solid interface area and preparing nanostructures on micro-structures.A hierarchical roughness was fabricated on H62brass surface by chemical etching with a FeCl3-HCl-H2O solution. The roughness consisted of terrace-like sidestep and etch pit with average pore diameter varied from6.2to8.3μm. The brass surface exhibited hydrophobic properties, with a water contact angle of about131.8°and contact angle hysteretic of about5.6°. The effect of etching time on the hydrophobic of the surfaces was investigated. The results indicated that the etching time played an important role in the formation of hierarchical roughness and of a high contact angle. With the increase of etching time, the side-step structure formed on the surface and its edge became regulation gradually, and the contact angle gradually increased until the side-step disappeared. The possible mechanism of the formation of hierarchical roughness was proposed. The wettability of brass surface was chiefly discussed on the basis of the Wenzel, Cassie and Limited Liquid-Solid Interfaces theories. The results showed that the Limited Liquid-Solid Interfaces theory is more reasonable in characterizing the wettability of rough surface. Corrosion resisting property of hydrophobic brass surface was investigated by artificial marine water soak and electrochemical polarization method respectively. The experimental results indicate that corrosion resistance could be enhanced by hydrophobic, and the better hydrophobic, the better corrosion resistance.A hydrophobic film was fabricated on H62brass surface by solution growth method with myristic acid alcohol solution, and exhibited good hydrophobic property, with a water contact angle of about148.3°. The film consisted of structures like chrysanthemum flower with average100nm thick,10μm width and50μm length. The chrysanthemum structure grown big and became more with the self-grown time increasing but be broken and accumulated when solution concentration increasing. Infrared spectrum analysis approved that the film is saturated fatty acid salt. Corrosion resisting property of hydrophobic film was investigated by soak and electrochemical polarization method respectively. The results indicate that the film show a good corrosion resistance property in acid, alkali and organic solvent solution, and improved anti-corrosion property of brass surface greatly.