A novel hybrid composite composed of albumin, WO3, and LDHs film for smart corrosion protection of Mg alloy

Abstract

The present study reports for the first time the fabrication of stable smart coatings on AZ31 Mg alloy based on the decoration of layered double hydroxide (LDHs) film by soft protein molecules functionalized by n-type semiconductor nanoparticles. For this goal, the LDHs film fabricated on the plasma electrolysis film of Mg alloy was immersed in a solution containing WO3 nanoparticles functionalized albumin, and the results were compared with the process in which LDH film was immersed in a homogenous solution of albumin. The deposition of ALB modified by WO3 nanoparticles altered the typical morphology of LDH film, forming a nest-like structure that gives rise to potential barrier formation at the interface which hinders ease of charge transport across the layer. Per electrochemical assessments in a 3.5 wt % NaCl solution, it was proposed that albumin modified by WO3 nanoparticles would cut off the electrons-supplying path at the surface of LDH film and transports them to the outside of the primer. Hence, it is assumed that the LDH-ALB-WO3 composite may effectively capture the corrosive ions during the corrosion. The remarkable improvement of the anticorrosion property of this film was connected with the increase in barrier to diffusion, prevention of charge transport by the WO3 nanoparticles modified albumin as well as the very large surface area available for the liberation of dopant due to the flake structure of LDH film. The electrochemical mechanism underlying the high corrosion resistance of the LDH-ALB-WO3 film was also revealed by Mott-Schottky (MS) analysis.