Novel multifunctional nanocomposites containing graphitic carbon nitride/silanized Nb2O5 nanofillers for the protection of steel surfaces in the automobile industry

Abstract

The inorganic nanofiller niobium pentoxide (Nb2O5) was altered with [3-(2-aminoethylamino)propyl]trimethoxysilane (AEPS) and the resulting AEPS/Nb2O5 was encased with graphitic carbon nitride (GCN) in pure epoxy resin (EP). The protection performance of mild steel coated with epoxy in the presence of various concentrations of GCN encapsulated in silanized Nb2O5 was investigated using electrochemical techniques in a marine environment. A limiting oxygen index (LOI) test showed that GCN/AEPS-Nb2O5 considerably enhanced the flame retardancy properties of the epoxy coating. The PHRR and THR values for EP-GCN/AEPS-Nb2O5 significantly decreased by 81 % and 69 %, respectively, compared to those of pure EP, showing that the material is more flame-retardant. The results of salt spray tests showed that the addition of GCN/AEPS-Nb2O5 enhanced corrosion protection and reduced water absorption. Even after 960 h of exposure to seawater, epoxy-GCN/AEPS-Nb2O5 exhibited increased coating resistance of 8.99E9 Ω.cm2, according to the EIS measurements. According to SECM research, coated steel made of the EP-GCN/AEPS-Nb2O5 nanocomposite has the lowest degree of ferrous ion dissipation (1.0 I/nA). According to the FE-SEM/EDX results, the decomposition products of silanized GCN were enhanced, generating a sturdy inert nanolayered coating. To prevent ions from penetrating the specimen, EP-GCN/AEPS-Nb2O5 crystallizes into a strong, inert coating, has greater adhesive strength, and can endure prolonged immersion without losing its integrity. Therefore, the EP-GCN/AEPS-Nb2O5 nanocomposite could act as a viable coating component in the automobile industry.