Fabrication And Mechanism Of Biomimetic Superhydrophobic And Corrosion Resistance On Magnesium Alloy Surface

In recent years, nonferrous metals have been used wildly due to the rapiddevelopment of electronic, aerospace, automotive, machinery manufacturing, precisionequipment. Magnesium alloys have been applied widely in various field due to theirspecial advantages including high specific strength and specific stiffness in thenonferrous metals. However, its application and development are restricted due to highmetal reactivity and poor corrosion-resistant. In this paper, the biomimeticsuperhydrophobic surfaces were fabricated via laser processing, chemical etching andelectrodeposition on the AZ91D magnesium alloy according to the typicalhydrophobicity surfaces of the plants and animals in the nature, and the samples showedthe good corrosion resistance. We also fabricated the superhydrophobic surface basedon the biological principle of intelligent control on AZ31magnesium alloy surface byanodic oxidation method, and researched the superhydrophobic and superhydrophilicreversible transformation.The obtained samples were characterized by scanning electron microscopy (SEM).The contact angles were performed with a contact angle meter (CA). The surfacechemical constituents were examined by X-ray photoelectron spectroscopy (XRD),fourier transform infrared spectrophotometer (FTIR) and energy spectrum (EDS). Thecorrosion resistance evaluation was tested by electrochemical analyzer.The biomimetic hydrophobic surfaces were fabricated by laser processingcombined with chemical etching. First the micron pits processed with the laser roughenthe processor, and then flower-like microstructure appeared after the chemical etchingof aqueous AgNO3, last the hydrophobic surfaces with the water contact angle of138.4°were fabricated after immersing in DTS solution. Moreover, the corrosion resistance ofhydrophobic surface was improved by means of electrochemical measure.The biomimetic superhydrophobic surfaces were fabricated via electrodeposition.The superhydrophobic surface with the water contact angle of160.8±1°and the rollangle of1.8±1°were coated on AZ91D magnesium alloy by electroplating, which wasprepared under the current density was15mA/cm2, and1.0mol/L the electrolyte for3min. The micro/nanoscale cauliflower-like cluster binary structures were fabricated. The anticorrosion behavior of the biomimetic super-hydrophobic film was enhanced bymeans of electrochemical measure in detail compared with the AZ91D magnesium alloy.Moreover, the as-prepared surfaces exhibited super-hydrophobicity with selfcleaningand good long-term stability under the pH between2to12.The biomimetic superhydrophobic surfaces with the wettability alteration werefabricated by anodic oxidation. First the micro/nanostructure films were fabricated onthe magnesium alloy surface by anodic oxidation, and then modified of stearic acid, lastthe as-prepared superhydrophobic surfaces were obtained with the water contact angleof163.8±1.5°. The superhydrophobic surface showed superhydrophobicity when thetemperature was below200℃, and the prepared superhydrophobic surfaces switched tosuperhydrophilic surfaces when the heat treatment temperature reached to300℃.However, the superhydrophilic surfaces switched to superhydrophobic surfaces viaagain modification. In addition, the corrosion tests were indicated that the preparedAZ31corrosion resistance was improved obviously.