Fabrication and properties of super-hydrophobic microstructures on magnesium alloys by laser–chemical etching

The super-hydrophobic microstructures were fabricated on the surface of AZ91 magnesium alloy by laser–chemical composite etching and stearic acid modification. The results show that the special concave and convex structures and grooves arranged in micro-scale were formed on the surface of specimens after laser etching. The sharpened grid grooves and rice-husk-like structures were constructed on the surface after CuCl2 solution etching. After laser–chemical composite etching and stearic acid modification, the surface presents good super-hydrophobicity and low adhesion with the water contact angle of 158.4°. Moreover, water droplets can easily roll off the surface of super-hydrophobic samples and carry contaminants along the rolling path. The corrosion resistance test shows that the magnesium alloy with super-hydrophobic structure has higher self-corrosion potential, lower self-corrosion current density and significantly higher impedance, indicating that it has good corrosion resistance.