Applied Surface Science, Vol.478, 150-161, 2019
Achieving an acid resistant surface on magnesium alloy via bio-inspired design
Developing acid-resistant magnesium alloys is challenging because of the high chemical reactivity of magnesium in acidic media. In this work, a bio-inspired strategy by taking advantage of the super-hydrophobic effects on lotus leaves is described. The self-layered coating consisting of an inner compact layer and outer Mg-Al layered double hydroxide (LDH) microsheet-based layer prepared hydrothermally exhibits enhanced corrosion resistance in saline solutions but cannot resist corrosion in sulfuric acid. After depositing a fluorocarbon polymer film on the microsheets using a polytetrafluoroethylene (PTFE) target by magnetron sputtering, a super-hydrophobic surface is created on the magnesium alloy. Compared to the surface modified hydrothermally, the super-hydrophobic surface provides better corrosion protection in H2SO4 due to trapped air pockets in the microsheet array. The dual process offers a promising means to mitigate corrosion of magnesium alloys in acidic media.
Keywords:Magnesium alloy;Hydrothermal treatment;Magnetron sputtering;Super-hydrophobic surface;Corrosion resistance