## 1 Introduction  
It is known that the damage of petrochemical equipment, oil and gas pipelines, and other infrastructure caused by corrosion of metals, has caused severe waste of resources, environmental pollution, and potential safety problems. One of the most cost-effective ways to prevent metal corrosion is the physical barrier coating, which creates an effective barrier between the metal substrate and the corrosive environment [1]. Epoxy resin coatings have been widely been in the coating industry due to these stable chemical properties, excellent electrical insulation rot, low cure shrinkage, high tensile strength and strong adhesion, and as the most effective method to inhibiting corrosion of the metal substrate [2; 3]. However, the traditional epoxy resin anticorrosive coatings are typical solvent-based coating systems, which contain a certain proportion of volatile organic compounds (VOCs) that cause health hazards and environmental problems. In recent years, many countrieshave legislation restricting emissions of VOCs [4; 5]. Therefore, it is imperative to develop low-cost, low-viscosity, easy-to-clean, high-performance, and environmentally-friendly water-based coatings to replace solvent-based epoxy coatings. Waterborne epoxy coatings have been extensively used due to their excellent adhesion, chemical resistance, and low shrinkage. And have been commercialized for nearly half a century [3; 6]. However, the traditional waterborne epoxy resin system still has some defects. Waterborne epoxy resins usually contain a large amount of hydrophilic groups and surfactants, so that a large number of microporous channels are formed after curing. It shows more permeability to corrosive substances (ie H\({}_{2}\)O, O\({}_{2}\), and Cl\({}^{-}\)) and it cannot provide long-term corrosion protection for metal substrates [7]. Therefore, the application of waterborne epoxy resin in the coatings market is restricted. In order to address these problems, many researchers have begun to apply nanotechnology to waterborne epoxy coatings to improve the corrosion resistance of waterborne coatings. Graphene and graphene derivatives can significantly improve the resistance of waterborne epoxy coatings due to their large specific surface area, high mechanical properties, good thermal stability, and outstanding barrier effect. Corrosion performance and other properties have become a research hotspot in the coating industry [8; 9]. Despite the great breakthroughs in the field of graphene-based waterborne epoxy coatings, there are still some shortcomings in the application of graphene. For example, the strong van der Waals force and high specific surface area cause it to easily aggregate together, can't to form a stable chemical bond with water and organic matter and the interface bonding force with the resin decreases, which limit their applications in coatings [10]. It is found that the inorganic nanomaterials, SiO\({}_{2}\), TiO\({}_{2}\), Fe\({}_{3}\)O\({}_{4}\), ZnO, etc., are supported on the surface of graphene oxide to prepare a graphene-inorganic nanocomposite with synergistic effect. Depositing nanoparticles not only can prevent graphene oxide nanosheets from restacking, but also endow a new functionality to graphene oxide [11; 12; 13]. At present, graphene-inorganic nanocomposites have been widely used in photocatalysts, electronic sensors, and biomedical fields [14; 15; 16], and the use of graphene-inorganic nanocomposites as fillers can also have a synergistic effect on improving the corrosion resistance of the coating. [PERSON] et al. [17] reported that nano-ZnO loaded graphene oxide/epoxy composites were successfully prepared by loading nano-ZnO on the surface of graphene oxide and compounding with epoxy resin. Through a series of characterizations, it is found that nano-ZnO can be uniformly dispersed on graphene oxide, which not only does not change the structure of graphene oxide, but also improves the agglomeration of graphene oxide and also reduces the hydrophilicity of graphene oxide.