Corrosion protection behaviour of sol–gel derived N,N-dimethylthiourea doped 3-glycidoxypropyltrimethoxysilane on aluminium

• Development of GPTMS based sol–gel coating for protection of Al.
• Doping of N,N-dimethylthiourea into GPTMS based sol–gel matrix.
• The doping of DMU enhanced the hydrophobic nature of the GPTMS sol–gel coating.
• The protective nature of the coating was revealed by EIS, PDS, SEM and XRD studies.

The present work describes the anticorrosion features of inhibitor doped sol–gel coating on Al metal. Sol–gel coatings were prepared by using 3-glycidoxypropyltrimethoxysilane (GPTMS) as parent precursor. In order to improve the corrosion resistance property of coating, N,N-dimethylthiourea was added into the sol–gel matrix. The corrosion inhibitor doped sol–gel coating on metal was characterized by Fourier transform infrared analysis (FTIR) and scanning electron microscope (SEM). Inhibition effect of N,N-dimethylthiourea doped GPTMS coating on Al substrates in 1% NaCl solution was investigated using electrochemical impedance (EIS) and polarization studies. EIS results showed that the corrosion resistance of sol–gel coating significantly improved upon addition of N,N-dimethylthiourea. The study had outlined the nuances of doping an organic inhibitor to enhance the protection ability of sol–gel coating on Al metal.