Evaluation of the corrosion protection performance of mild steel coated with hybrid sol-gel silane coating in 3.5 wt.% NaCl solution

This study aims at studying the effect of silane hydrolysis time and concentration on the corrosion protection performance of an eco-friendly hybrid silane coating based on tetraethylorthosilicate (TEOS) and trimethoxymethylsilane (TMOMS) on mild steel substrate. By electrochemical impedance spectroscopy (EIS) and salt spray test the corrosion evaluations were done. Results of Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and water contact angle tests measurements revealed the effective impact of the hydrolysis time and silane concentration on the curing process of the coating. Results revealed that the mixture of 50% silanes (TEOS/ TMOMS: 50/50 w/w) hydrolyzed for 24 h resulted in the highest corrosion resistance. The enhancement in protective performance of the hybrid coating was connected to the better condensation reaction, denser Si-O-Si network formation and less hydrophilicity of the coating.