Influence of pH on corrosion resistance of electrodeposited Mg-Fe LDH composite films on Mg alloys WE43

Abstract

Layered double hydroxide (LDH) are widely studied as corrosion inhibition coatings for magnesium (Mg) alloys due to their nano-lamellar structure and anion-exchange ability. The two common approaches in synthesising LDH films on Mg alloys are co-precipitation and hydrothermal treatment. Recently, electrodeposition has drawn more interest as a potential synthesis approach due to the low cost, ease of control, one-step method, and ability to create a compact film. In this work, Mg-Fe LDH film was synthesised on magnesium hydroxide, Mg(OH)₂ layer formed on Mg alloy WE43 by electrodeposition approach with the as-prepared iron solution at different pH values. The effect of pH of the solution (3.0, 5.0 and 7.0) on the formation of LDH films was investigated using Field Emission Scanning Electron Microscopy (FESEM). Additionally, the surface chemical components of the film were obtained by Fourier Transform Infrared Spectrometer (FTIR). All the LDH composite films synthesised at different pH values undergo electrochemical tests in Hank’s Balanced salt solution (HBSS). All samples promote corrosion resistance of WE43 with the LDH film synthesised at pH 3.0 provided the highest inhibition efficiency (I.E) of 94.48 % and resistance polarisation value of 3559. 07 Ωcm².