Flame retardant and corrosion protection performance of multifunctional nanocomposites containing graphitic carbon nitride/silanized Ta2O5 nanofillers for the protection of steel surface for industrial applications

Inorganic nanofiller tantalum pentoxide (Ta2O5) was modified using N-(2-mercaptoethyl)3-(trimethoxysilyl) propylamine (MEPS), and the resulting MEPS/Ta2O5 was encased with graphitic carbon nitride (GCN) in the pure epoxy resin (EP). The protection performance of mild steel coated with epoxy in the presence of various concentrations of GCN contained in silanized Ta2O5 was investigated using electrochemical methods in seawater. It was found that the 0.6 wt% of GCN/MEPS-Ta2O5 was identified as the optimum wt% which gave the maximum resistance. Thermogravimetric analysis (TGA) and the limiting oxygen index (LOI) test showed that the GCN/MEPS-Ta2O5 considerably enhanced the flame retardancy properties of the epoxy coating. The PHRR and THR values for the EP-GCN/MEPS-Ta2O5 significantly decreased by 80% and 73%, respectively, as compared to pure EP, showing that the material is more flame retardant. The results of salt spray tests showed that the combination of GCN/MEPS-Ta2O5 enhanced corrosion resistance and reduced water absorption. Even after 40 days of exposure to seawater, the epoxy-GCN/MEPS-Ta2O5 exhibited increased coating resistance of 9.49E10.Ω.cm2, according to the EIS measurements. According to SECM studies, coated steel made of EP-GCN/MEPS-Ta2O5 nanocomposite (1.0 I/nA) had the least amount of ferrous ion dissipation. The silanized GCN was discovered to be enhanced in the degradation products, generating a sturdy inert nanolayered coating. The newly created EP-GCN/MEPS-Ta2O5 coating has remarkable water-resistant properties with a WCA of 165°. The mechanical properties of the MEPS-Ta2O5 encapsulated in GCN have demonstrated good adhesion strength and hardness in the epoxy substrate. For mild steel coated with EP-GCN/MEPS-Ta2O5 (17.9 MPa), the adhesive power was enhanced before being immersed in seawater. In light of this, the EP-GCN/MEPS-Ta2O5 nanocomposite might function as a practical coating material for the industrial applications. [Display omitted] •The coating resistance of EP-GCN/MEPS-Ta2O5 nanocomposite was found to be 9.49E10 Ω.cm2.•The EP-GCN/MEPS-Ta2O5 showed greater flame retardancy with PHRR (80%) and 73% (THR) reductions.•The EP- EP-GCN/MEPS-Ta2O5 coatings on steel controlled the dissolution of Fe to Fe2+ ions.•The superior hydrophobic behavior of EP-GCN/MEPS-Ta2O5 coating was confirmed by its WCA of 165º.•The EP-GCN/MEPS-Ta2O5 film displayed the enhanced adhesive strength (17.9 MPa)