Graphene Oxide Decorated with Titanium Nanoparticles to Reinforce the Anti-Corrosion Performance of Epoxy Coating

Abstract

Graphene oxide–titanium (GO-Ti) composite materials were fabricated using GO as a precursor and then anchoring nano titanium (Nano-Ti) particles on GO sheets with the help of a silane coupling agent. Then, the coating samples were prepared by dispersing GO, Nano-Ti particles, and GO-Ti in an epoxy resin at a low weight fraction of 1 wt %. The GO-Ti composites were investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The dispersibility and anti-corrosion mechanism of the coatings were studied by sedimentation experiments, electrochemical impedance spectroscopy (EIS), SEM, and salt spray tests. The mechanical properties of the coatings were analyzed by friction and wear tests. The results showed that the Nano-Ti particles were successfully loaded on the GO surface by chemical bonds, which made GO-Ti composites exhibit better dispersibility in the epoxy than GO. Compared with Nano-Ti particles and GO, the GO-Ti composite exhibited significant advantages in improving the corrosion resistance of epoxy coatings at the same contents, which was attributed to the excellent dispersibility, inherent corrosion resistance, and sheet structure. Among the different proportions of composite materials, the GO-Ti (2:1) material exhibited the best dispersibility and corrosion resistance. In addition, the composite material also greatly improved the wear resistance of the coating.

Recent Advances and Trends of Nanofilled/Nanostructured Epoxies

“…Graphene ( Figure 4 ), with its most important derivative graphene oxide (GO), was probably the first compound of this broad family proposed to manufacture high-performance nanocomposites due to its unique shape (two-dimensional crystals with an average thickness of about 1 −10 m and diameter 0.5–5 μm) and outstanding electrical (with a conductivity of 6 × 10 5 S/m), mechanical (in terms of tensile strength and especially Young’s modulus, the latter being equal to 1.1 TPa), thermal (conductivity around 5000 W/m·K), and barrier properties [ 16 ]. Its addition can provide a reinforcing effect to the epoxy matrix and multifunctionality for the most varied engineering applications (anticorrosive coatings, structural adhesives, thermal conductors) at lower costs than the more expensive carbon nanotubes, to fabricate electric and electronic devices, and also in the field of fiber-reinforced polymers [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. GO nanosheets, characterized by an extremely high surface area (~2630 m 2 /g), may represent a feasible alternative to functionalized/unmodified carbon nanotubes also when enhancements in mechanical, electrical, and thermal properties are mostly required for a conventional epoxy [ 24 ].…”

“…Often, the functionalization of the surface of a nanofiller is achieved by treatment with silane solutions, such as in the case of nanoclays [ 75 ], graphene [ 92 , 93 ], boron nitride [ 87 ], and SiO 2 nanoparticles [ 64 ]. The silane can also act as a coupling agent, allowing the graft of other chains/compounds on the surface of the nanofiller, synergistically improving the nanocomposite performance [ 22 , 94 ].…”

“…In particular, the higher the impedance, the better the corrosion resistance. Corrosion of coated substrates is influenced by absorption and diffusion of the corrosive agent into the coating, which mainly depends on the presence of voids or defects, but also on the adhesion of the coating to the metallic substrate [ 22 , 92 , 122 , 125 ]. The corrosion resistance is enhanced when the nanoparticles fill the micro-pores in the epoxy polymer, promoting a tortuous diffusion path, similar to a “labyrinth effect”, able to hinder the infiltration of corrosive agents into the coating [ 70 , 73 , 121 , 125 , 136 ].…”

Enhancement in Nanomechanical, Thermal, and Abrasion Properties of SiO2 Nanoparticle-Modified Epoxy Coatings

“…Luo et al [22] reported that basalt flake modified epoxy coatings that were incorporated with 3% nanosilica showed excellent chemical and mechanical performance. Yuan et al [23] reported that the incorporation of titanium nanoparticle modified graphene oxide significantly improved the corrosion and wear resistance of the epoxy coatings.…”

Improving pitting corrosion resistance of the commercial titanium through graphene oxide-titanium oxide composite

“…Metal corrosion has become a very serious issue. The global annual corrosion cost is estimated to be around 3–5% of the GDP [ 13 ]. Coating on metal substrates to reduce corrosion is widely used as an effective solution.…”