Title : Improving the corrosion resistance of AISI 304 stainless steel through sol-gel derived MTES/Polysilazane hybrid composite coatings
Abstract:
AISI 304 stainless steel, widely used in different industrial applications. However, this metallic substrate suffers from limitations such as low wear resistance and susceptibility to pitting and stress corrosion cracking, particularly in chloride environments. The use of barrier coating on stainless steel is an efficient strategy to improve the corrosion resistance and lifetime of this substrate in chloride solution. In this work, a hybrid barrier coating based methyltriethoxysilane (MTES) and poly(methylvinyl)silazane (Durazane 1800) has been developed by sol-gel route. The MTES/polysilazane solution was synthesized using tetra-n-butylammonium fluoride (TBAF) and n-butyl acetate (NBTA) and was deposited on stainless steel by dip coating method. Fourier-transform infrared spectroscopy (FTIR) studies demonstrated that the incorporation of MTES to polysilazane backbone led to increase crosslinking density and improve curing of polysilazane derived network. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and water contact angle tests confirmed that the hybrid coating exhibited superior barrier performance, enhanced corrosion resistance, and improved hydrophobicity compared to bare polysilazane coatings. After 4 weeks of immersion in 3.5 wt.% NaCl solution, the hybrid coating demonstrated sustained high impedance at low frequency, phase angle value near to 85º, indicating its potential as a high-performance, durable coating for industrial applications.
