Poly(methyl methacrylate) intercalated layered double hydroxide film with enhanced alkaline corrosion resistance for aluminum alloy AA6061

The oriented growth of Zn-Al LDH film perpendicular to the surface of AA6061 substrate was confirmed by scanning microscopy image and X-ray diffraction pattern. The LDH film achieved a complete surface coverage on the AA6061 substrate and exhibited strong corrosion resistance in NaOH solution (pH of 13). Furthermore, a preparation protocol for poly(methyl methacrylate) (PMMA)-LDH composite film was demonstrated. LDH film intercalated only with PMMA but not polyurethane demonstrated greatly enhanced alkaline corrosion resistance, showing a more positive corrosion potential and reduced corrosion current by four orders of magnitude in electrochemical polarization spectroscopy. The enhancement in corrosion resistance by PMMA intercalation could be attributed to the increasing compactness in the LDH film and increasing hydrophobicity.