Anticorrosion Field Research Articles

Ce/LDHs coating modified by GO applied on AZ31 alloys corrosion protection

Layered double hydroxides (LDHs) exhibit anion exchange properties and adjustable characteristics, which make them suitable for applications in the field of anticorrosion. However, the smooth growth pattern of a single LDHs nanosheet limits its effectiveness in blocking corrosive media. Graphene oxide (GO) has a large specific surface area and numerous oxygen-containing functional groups on its surface, which can form strong interactions with polar molecules. This inhibits the migration of small ions, such as Cl−. In this work, Ce was incorporated into a micro-arc oxidation (MAO) coating on the AZ31 alloy by immersion in a cerium salt solution, and GO was incorporated using a hydrothermal solution to prepare layered double hydroxide composite coating (Ce/LDHs-G). The significance of charge transfer resistance ( Rct) mainly reflects the charge transfer process at the electrode/electrolyte interface. The Rct of Ce/LDHs-G increased by one order of magnitude compared to MAO coating. The corrosion current density ( icorr) of Ce/LDHs-G coating was 3.73 × 10−8 A cm−2, lower than that of MAO coating (1.56 × 10−6 A cm−2). Additionally, the cumulative hydrogen evolution over 336 h was lower, indicating that Ce/LDHs-G coating provides effective corrosion protection for the AZ31 alloy.

Microfluidic Electrospinning Core-Shell Nanofibers for Anti-Corrosion Coatings With Efficient Self-Healing Properties.

Self-healing materials have been extensively explored in metal anti-corrosion fields. However, improving the self-healing efficiency remains a significant work that severely limits their further development. Here, a strategy to fabricate anti-corrosion coatings with efficient self-healing properties based on microfluidic electrospinning technologies and UV-curable healing agents is reported. The damaged composite coating contains core-shell nanofibers that can be completely healed within only 30min, indicating an outstanding healing efficiency. The corrosion current density (Icorr) of the composite coatings containing core-shell nanofibers (abbreviated as composite coatings) is lower than the coatings without any fibers (abbreviated as pure resin coatings) during the test of repeated damage and healing cycles, showing superior resistance to corrosion and repeated self-healing property. The composite coating has even better mechanical properties such as tensile strength, bending strength, and impact strength than the pure resin coating, which are explained by simulating the deformation process. These excellent properties greatly improve the practicability of self-healing coatings in the application of anti-corrosion, especially in some special fields.

Superhydrophobic Waterborne Epoxy Composite Coating with Good Mechanical Properties, Icing Resistance, Self-Cleaning Properties, and Corrosion Resistance.

Epoxy resins with higher corrosion resistance typically employ environmentally harmful organic solvents such as xylene, while the corrosion resistance of waterborne epoxy resins, which are relatively environmentally friendly, is not as good as that of oil-based epoxy resins. In this study, by coating the surface of waterborne epoxy resin with a superhydrophobic zinc oxide coating, the corrosion resistance of waterborne epoxy resin was enhanced. During the initial immersion, its impedance value can reach 1010 Ω·cm2. The superhydrophobic nature of the coating itself also ensures the surface's resistance to immersion, delaying the intrusion of corrosive media into the coating. Furthermore, this coating exhibits good mechanical properties, self-cleaning performance, anti-icing performance, and so on. The introduction of superhydrophobic surfaces greatly optimizes the performance of traditional waterborne epoxy resin coatings, opening up directions for the metal anticorrosion field of coatings. Meanwhile, during the EIS testing of the superhydrophobic coating, we observed the occurrence of negative impedance in the results. After studying, we speculated that this phenomenon might be related to the degree of wetting of the superhydrophobic coating. Based on this conjecture, we can evaluate the basic properties of the superhydrophobic coating through this phenomenon.

Preparation and properties of a simple super‐hydrophobic carbon fiber composite surface

AbstractSuper‐hydrophobic surface is widely used in waterproof, antifouling, and anticorrosion fields because of its unique wetting characteristics. However, the rough structure of super‐hydrophobic surface is easily damaged in service, which leads to the loss of various properties, making it difficult to apply super‐hydrophobic surface on a large scale in actual production. In this paper, epoxy resin was used as adhesive, mixed with hydrophobic silica particles and sprayed on the surface of carbon fiber composites. After curing, the surface of super‐hydrophobic carbon fiber composites with contact angle of 158 ± 2° and sliding angle of 1 ± 0.5° was formed. The surface had excellent dynamic water repellent performance, and the droplets could bounce more than three times on the surface. Furthermore, the super‐hydrophobic surface had excellent wear resistance and mechanical stability. After the friction damage test, the surface structure of the sample was slightly damaged. The amount of wear was small, and the surface was still in super‐hydrophobic state. Through soaked in solutions with different pH values, the microstructure of the surface was not obviously damaged by corrosion, the contact angle of water droplets was greater than 155°. The preparation method of super‐hydrophobic surface of carbon fiber composite proposed in this study is simple and rapid, and the prepared surface has excellent performance, the practical application of super‐hydrophobic surface is promoted.

Anisotropic dispersion promoting and passivation protecting of CA@JNs@Zn2+ Janus nanosheets on epoxy anticorrosive coatings

Defects in the curing process of epoxy coatings tend to deteriorate the anticorrosion performance of the coatings. An important way to enhance the anticorrosion performance of epoxy coatings is to add flaky fillers. In this paper, anisotropic Janus nanosheets (JNs) were prepared and modified by cardanol (CA) and Zn2+. Then, the obtained CA@JNs@Zn2+ Janus composite nanosheets were introduced into epoxy coatings. When the content of CA@JNs@Zn2+ is 0.2 %, the mechanical properties and corrosion resistance of the coating were effectively improved. The tensile strength of 0.2 %-CA@JNs@Zn2+/EP coating is 79 % higher than that of pure epoxy coating. The EIS analysis showed that the low-frequency impedance of the coating remained as high as 16.45 Gohm·cm2 after 35 days of immersion, and remained above 10 Gohm·cm2 during the whole immersion period, which demonstrating the optimal corrosion resistance. This paper provides a theoretical basis for the preliminary application of Janus material in the field of anticorrosion, and the prepared composite coatings are expected to be used for anticorrosion in harsh environment.

Bioinspired polydopamine nanosheets for the enhancement in anti-corrosion performance of water-borne epoxy coatings

The utilization of two-dimensional (2D) inorganic nanomaterials as nanofillers in the anticorrosion fields has garnered significant attention due to their exceptional barrier properties. However, uniform dispersion of nanofillers and good interfacial compatibility with organic coatings still remain a substantial challenge. Consequently, there is a need to explore novel and eco-friendly 2D nanomaterials for anticorrosive applications. In this study, two-dimensional polydopamine nanosheets (PDANS) were synthesized through a facile template method, and incorporated into water-borne epoxy (WEP) coating as green anticorrosive additives. Compared to WEP coating, the prepared PDANS/WEP coatings exhibited significantly enhanced corrosion protection performance, with a nearly 50% reduction in water uptake and a 22-fold increase in the |Z|f=0.01Hz value at a 0.5 wt% PDANS loading. These improvements can be attributed to the favorable interfacial compatibility between PDANS and WEP matrix, as well as the superior barrier properties of PDANS. Furthermore, local electrochemical impedance spectroscopy (LEIS) results demonstrated that the damaged PDANS/WEP coating provided enhanced corrosion protection by inhibiting steel corrosion through the chelating interaction between PDANS and steel, thereby reducing the coating delamination. Based on these findings, it can be inferred that PDANS hold great promise for the development of innovative anticorrosive coatings.

Heat dissipation performance of graphene anti-corrosive coatings for high-heat flow equipment

Graphene materials have broad development prospects in the field of anticorrosion and heat dissipation of high-heat equipment such as transformers in the State Grid. In this paper, the graphene anti-corrosion coating is used as a thermal interface material, and the thermal resistance and emissivity of the graphene anti-corrosion coating samples are studied by combining the thermal resistance detection of electronic devices and systems with the emissivity measurement technology. The thermal resistance test was carried out on the samples containing 1%–10% graphene anti-corrosion coatings, and the emissivity of the samples at 30 °C, 50 °C, 70 °C, and 90 °C was measured respectively. The experimental results show that the method has important theoretical and application significance for the optimization and application of heat dissipation of graphene materials.

GO-functionalized MXene towards superior anti-corrosion coating

MXene flakes shows the great potential in corrosion protection area owing to their lamellar structure and remarkable mechanical features. However, these flakes are highly susceptible to oxidation, which results in their structure degradation and restrict their application in anti-corrosion field. Herein, graphene oxide (GO) was used to functionalize Ti3C2Tx MXene through TiOC bonding to fabricate GO-Ti3C2Tx nanosheets, which proved by Raman, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR). GO-Ti3C2Tx nanosheet inclusion into the epoxy coating and their corrosion performance in 3.5 wt.% NaCl solution with 5 MPa pressure was evaluated through electrochemical techniques including open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) along with salt spray. Results indicated that GO-Ti3C2Tx/EP presented superior anti-corrosion capability, the impedance modulus at low frequency (|Z|0.01 Hz) was above 108 Ω cm2 after 8 days’ immersion in 5 MPa environment, which was 2 orders of magnitude higher than that of the pure epoxy coating. Scanning electron microscope (SEM) and salt spray images demonstrated that the epoxy coating loaded with GO-Ti3C2Tx nanosheet could provide robust corrosion protection for Q235 steel via the physical barrier effect.

Smart healable and reportable anticorrosion coating based on halloysite nanotubes carrying 8-hydroxyquinoline on steel

Integrating healable and reportable ability to sustain new-generation smart anticorrosion coatings with long-term durability is highly desirable to accommodate the development of marine industries. Herein, a new type of dual-function coating is designed to fulfill the needs. Through introducing the smart nanocontainers based on the core of HNTs loaded with 8-hydroxyquinoline (8HQ) and the shell made from sodium tripolyphosphate-chitosan (CS) into conventional epoxy matrix, the smart healable and reportable anticorrosion coating on carbon steel (Q235) was developed. Electrochemical impedance spectroscopy (EIS) and salt spray measurement indicated the corrosion inhibition effect of the nanocontainers and healable performance of composite coatings. Benefitting from the 8HQ, the designed waterborne epoxy coating displayed higher low-frequency modulus after 60 days of immersion, confirming the long-term protection ability. Besides, the composite coating exhibited obvious dark-green color at damaged region to timely sense and report the local corrosion in 30 min of immersion tests. This smart coating with sensitive corrosion visualization and well-performed healable properties holds great potential in actual anticorrosion fields.

A non-fluorinated superhydrophobic composite coating with excellent anticorrosion and wear-resistant performance.

The facile and low-cost fabrication of fluorine-free superhydrophobic metal surfaces for anticorrosion remains a challenging issue. Here, we report a superhydrophobic coating based on polyacrylate/SiO2 nanoparticles/graphene oxide sheets through a simple yet environmentally friendly method. The as-prepared composite coating sprayed on metal surfaces exhibits excellent superhydrophobic and corrosion-resistant properties. Furthermore, the coating surface possesses good anti-wear performance and remains superhydrophobic after harsh abrasion tests. Prospectively, the developed non-fluorinated superhydrophobic coating opens up opportunities for the application in industrial anticorrosion field.

Photo-responsive rapid self-healing polyurethane elastomer with anticorrosion and antibacterial functions

In this paper, polyurethane (PU) with polyethylene glycol as a soft segment and isophorone diisocyanate as a hard segment were designed and synthesized. Copper complex (Cu(HD)2) was synthesized in PU preparation, bringing excellent self-healing, photothermal and antibacterial properties. The content of Cu2+ accounted for less than 2wt% of PU elastomer. Cu(HD)2 acted as a chain extender and provided coordination bonds for elastomer to promote the self-healing process. Experiments showed that Cu(HD)2 exhibited excellent photothermal properties in PU. The maximum temperature of the samples after 5 min irradiation under a sunlight simulator could reach 120 °C. The results of the self-healing experiment showed that mechanical properties of PU could be recovered by nearly 90%, and electrochemical protection performance could be recovered by nearly 100%. Antibacterial experiments proved that PU could release Cu2+, forming an antibacterial ring around PU. PU has excellent application in the field of anticorrosion and antibacterial coatings.

Thermo-driven oleogel-based self-healing slippery surface behaving superior corrosion inhibition to Mg-Li alloy

Bioinspired by Nepenthes, lubricant infused surfaces (LIS) have attracted widespread attention in the field of anticorrosion. However, the lubricant coating has some disadvantages such as complex construction processing and easy loss of oil phase in air or dynamic water phase. In this study, oleogel is infused into a lotus leaf inspired super-hydrophobic matrix to form an oleogel infused surface (OIS) for enhancing corrosion resistance of active Mg-Li alloy. For reserving oleogel, firstly, a facile one-step electrodeposition method is used to construct super-hydrophobic surface (SHS) composed by samarium/myristic acid complex micro-nano flower structure onto Mg-Li alloy. The coating exhibits excellent superhydrophobic property at a static contact angle of 160° by applying 30 V electrolysis for 30 min. The protection efficiency of single SHS highly relates with the metal itself. For short period immersion in water phase, SHS can afford protection to Mg-Li alloy. However, the long-term immersion will see the rapid failure of SHS, and the high activity of Mg-Li alloy is one main reason. We assume that SHS cannot be a good choice for protecting Mg-Li alloy. Then, a Nepenthes inspired liquid coating is formed by infusing oleogel into the micro-nano structure by a spin-coating method. The liquid coating performs prominent corrosion resistance with Rct reaching as high as 1.51 × 1010 Ω cm². After the mechanical damage from the external environment, the liquid coating can realize self-repair through thermal assistance, and the liquid coating can still restore Rct up to 1.24 × 1010 Ω cm2 after healing. The corrosion resistance of the liquid coating remains strong by showing Rct as high as 1.14 × 109 Ω cm², even after immersion in representative corrosive 3.5 wt% NaCl solution for 30 d.

Preparation and performance of a composite epoxy coating based on modified hydroxyapatite

Hydroxyapatite (HAp) has been widely used in modern medicine because of its good biocompatibility and has become an important coating material for biological implants. However, it is seldom used in traditional metal anticorrosion field. In this paper, a PDA-HAp@f-Al2O3/EP composite anticorrosive coating was synthesized by modifying the surface of hydroxyapatite (HAp) with polydopamine (PDA) and using amino functional group silane (KH550) doped nano Al2O3 particles for metal anti-corrosion. The introduction of polydopamine (PDA) and Al2O3 solved the problem of poor dispersion in the epoxy coating which can be obviously conducted from the decrease of agglomeration in the SEM images of both materials and composite coatings. Electrochemical impedance spectroscopy (EIS) showed that PDA-HAp@f-Al2O3/EP coating had the smallest change range of breakpoint frequency (fb) and the highest low frequency (f = 0.01 Hz) impedance value compared with other coatings in the experiment of immersing in 3.5 wt% NaCl solution. In particular, the impedance of pure EP is only 9.93 × 104 Ω cm2 and that of PDA-HAp@f-Al2O3/EP is up to 1.19 × 108 Ω cm2 after immersing in 3.5 wt% NaCl solution for 30 days, which is 4 orders of magnitude different. The data obtained by fitting the coating equivalent circuit model (QC, Qdl, RC, Rct) also show that the coating has excellent anticorrosion performance. Besides, the anticorrosion mechanism of the coating is also studied. PDA-HAp@f-Al2O3/EP composite anticorrosion coating plays a barrier role first when the corrosive medium begins to invade, and then protects the coating by extending the path of the corrosive medium into the coating and the release of corrosion inhibitor. This study provides a broad prospect for the application of hydroxyapatite (HAp) in traditional anticorrosive work.

Anti-corrosion and self-healing behaviors of waterborne polyurethane composite coatings enhanced via chitosan-modified graphene oxide and phosphate intercalated hydrotalcite

Surface coating technology has been widely used in anti-corrosion field. A well-stacked layered material offers a strong barrier and labyrinth effect to improve the corrosion resistance of organic coatings. However, as a typical layered material, the hydrotalcite dispersion is unstable and prone to delamination. Herein, a strategy for grafting chitosan on graphene oxide and then electrostatic self-assembling with hydrotalcite was proposed. The graphene oxide was modified with chitosan to enhance its barrier performance and corrosion resistance, and then hydrotalcite was coated on the surface of graphene oxide through electrostatic self-assembly to improve the dispersion of hydrotalcite and the interfacial compatibility with resin. At the same time, PO43− between the hydrotalcite layers provides the coating with self-healing ability. Chitosan, graphene oxide and hydrotalcite nano-hybrid materials were introduced into waterborne polyurethane, and a corrosion-resistant coating with a thickness of about 40 μm was prepared. Excellent anti-corrosion behaviors were obtained through the synergistic effect of graphene oxide and hydrotalcite stacking due to the formation of a dense protective layer and the self-healing characteristics of chitosan and phosphate ions. This new type of waterborne polyurethane composite coatings offers broad application prospects in the research and development of high-performance self-healing anti-corrosive coatings.

Synthesis of Ti3C2 MXene@PANI composites for excellent anticorrosion performance of waterborne epoxy coating

Ti3C2 MXene nanosheets have become a research hotspot in the anticorrosion field owing to their excellent barrier performance and mechanical properties. However, the utilization of different etching agents for the preparation of Ti3C2 MXene nanosheets has positive or negative influence on corrosion protection of waterborne epoxy coating (WEP) for metal owing to their quiet distinct electrical conductivity. In this study, we successfully synthesized multilayer Ti3C2 MXene nanosheets, and Ti3C2 MXene@PANI composites, such that PANI with high doping levels were uniformly anchored on the Ti3C2 MXene nanosheets' surface via in situ intercalation polymerization. Moreover, we verified the LiF and HCl treatment of Ti3C2 MXene accelerated the failure of WEP coating, which can be attributed to its higher electrical conductivity caused by the intercalation of Li+ than that of HF treatment. Ti3C2 MXene@PANI composites significantly improved the corrosion resistance of the WEP coating, thus greatly resolving the accelerating corrosion issue of Ti3C2 MXene. 0.3 wt% or more Ti3C2 MXene@PANI-1.0/WEP coatings' corrosion current density, impedance modulus, and charge transfer resistance increased by 1–2 orders of magnitude than that of pure WEP and Ti3C2 MXene/WEP in 3.5 wt% NaCl after 10 days of immersion. These results demonstrated that the synergistic effect of Ti3C2 MXene nanosheets' barrier effect and PANI's passivation effect enable Ti3C2 MXene@PANI composites with lower electrical conductivity to achieve long-term and efficient corrosion protection in WEP coating for Q235 steel.

Construction and excellent photoelectric synergistic anticorrosion performance of Z-scheme carbon nitride/tungsten oxide heterojunctions.

The use of heterojunctions for metal corrosion protection is a highly innovative and challenging task. Based on the composition and structure of tungsten oxide-based heterojunctions, Z-scheme heterojunctions were designed and synthesized by the electrostatic self-assembly method using energy band-matched g-C3N4 and WO3 materials. Applied in the field of anticorrosion, they overcame the problems of poor reduction ability and transmission inefficiency of traditional materials. The Z-scheme heterojunctions ensured unidirectional electron transfer, while the aggregation of the retained strongly reduced electrons on the surface of the iron substrates provided a strong driving force for retarding corrosion occurrence. Meanwhile, the inherent shielding properties of the two-dimensional material g-C3N4 and the confinement of chloride ions as an electroactive layer hindered the penetration of the corrosive solution. After being corroded for 72 h, the corrosion impedance of the g-C3N4/WO3 heterojunction system was improved by 640.11% compared with the epoxy resin coating. In addition, the g-C3N4/W18O49 heterojunction was synthesized by using mixed valence tungsten oxide, which overcame the problems of photogenerated electron yield and lifetime, and enhanced the anticorrosion performance compared with a single g-C3N4 phase. This research provided ideas for designing efficient and environmentally friendly heterojunction anticorrosion materials.

Excellent anti-corrosion performance of epoxy composite coatings filled with novel N-doped carbon nanodots

Nanofillers play an important role in the field of anticorrosion. This paper focuses on the study of the anticorrosion performance of a novel N-doped carbon nanodots(CNDs) in epoxy coating. N-doped carbon nanodots(CNDs) with a size of about 100 nm is synthesized by hydrothermal method using citric acid as carbon source. The chemical structure and morphology of CNDs are studied by Fourier transform infrared spectroscopy(FT-IR), ultraviolet spectrophotometer(UV–vis), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The water absorption of the coating is studied by gravimetric method. The corrosion resistance of the coating is analyzed by electrochemical impedance spectroscopy(EIS). The results reveal that the corrosion resistance of epoxy coating is significantly improved by adding the appropriate amount of CNDs, as it can effectively reduce the porosity of the coating and extend the path of corrosive medium penetrating the coating, thus enhancing the corrosion resistance of the coating. After soaking in 3.5 wt% NaCl solution for 480 h, the low frequency impedance of the 0.15 wt% CNDs/epoxy nanocomposite coating is 1.85x1010 ohm·cm2, which is greatly improved compared with that of the pure epoxy coating (5.43 × 104 O·cm2). The water absorption result shows that the water absorption of the coating with CNDs content of 0.15 wt% is much lower than that of the pure epoxy coating. The corrosion resistance is greatly improved.

Corrosion Resistance of Ultrathin Two-Dimensional Coatings: First-Principles Calculations towards In-Depth Mechanism Understanding and Precise Material Design

In recent years, ultrathin two-dimensional (2D) coatings, e.g., graphene (Gr) and hexagonal boron nitride (h-BN), are intriguing research foci in the field of anticorrosion because their high air stability, excellent impermeability, high optical transparency, and atomistic thickness have endowed them with attractive anticorrosion applications. The microstructure of 2D coatings, coating–substrate interactions, and properties of 2D coatings on substrates in a variety of environmental conditions (e.g., at different temperatures, stresses, and pH values) are the key factors governing the anticorrosion performance of 2D coatings and are among the central topics for all 2D-coating studies. For many conventional experimental measurements (e.g., microscopy and electrochemical methods), there exist challenges to acquire detailed information on the atomistic mechanisms for the involved subnanometer scale corrosion problems. Alternatively, as a precise and efficient quantum-mechanical simulation approach, the first-principles calculation based on density-functional theory (DFT) has become a powerful way to study the thermodynamic and kinetic properties of materials on the atomic scale, as well as to clearly reveal the underlying microscopic mechanisms. In this review, we introduce the anticorrosion performance, existing problems, and optimization ways of Gr and h-BN coatings and summarize important recent DFT results on the critical and complex roles of coating defects and coating–substrate interfaces in governing their corrosion resistance. These DFT progresses have shed much light on the optimization ways towards better anticorrosion 2D coatings and also guided us to make a prospect on the further development directions and promising design schemes for superior anticorrosion ultrathin 2D coatings in the future.

Synthesis of ultrathin α-zirconium phosphate functionalized with polypyrrole for reinforcing the anticorrosive property of waterborne epoxy coating

As a classical two-dimension nanomaterial, α-zirconium phosphate (α-ZrP) with outstanding barrier property and non-conductivity has great potential application in anticorrosion field. However, the thicker layer thickness and lack of long-term anticorrosion property limit the application of α-ZrP. In this work, α-ZrP with the diameter of about 500 nm was prepared and then exfoliated to enhance the dispersion in waterborne epoxy coatings(WEC). Then polypyrrole (PPy) was used to encapsulate the exfoliated α-ZrP (E-ZrP) to obtain final nanomaterial(PPy-ZrP). XRD, FTIR, EDS mapping, SEM, TEM were employed to characterize the as-prepared nanomaterials. WECs with those as-prepared nanomaterials were fabricated by spray and the anticorrosion performance of WECs were tested by electrochemical impedance spectroscopy(EIS) test and salt spray test. At the end of the EIS test (60 days of immersion in 3.5 wt% NaCl solution), the PPy-ZrP/WEC exhibited the highest value of |Z|0.01 Hz (4.5 × 107 Ω·cm2), which is about two orders of magnitude higher than blank WEC. During the EIS test period, PPy-ZrP/WEC displayed better corrosion resistance than other WECs. As a two-dimension nanosheet with good dispersion in WEC, PPy-ZrP provided outstanding barrier property for WEC. And the passivation effect of PPy further enhanced the corrosion resistance of WEC.

Poly(m-phenylenediamine) encapsulated graphene for enhancing corrosion protection performance of epoxy coatings

Graphene (G) is regarded as a tremendous potential corrosion protection material owing to its perfect impermeability. However, the tendency of graphene nanosheets to agglomerate and the corrosion-promotion effect brought by its native high electrical conductivity seriously affect its anti-corrosion application. In this paper, high-energy ball milling was used to prepare graphene with excellent impermeability. Then, insulating poly(m-phenylenediamine) encapsulated graphene (G@PmPD, conductivity of 1.2 × 10−7 S cm−1) was prepared through non-covalent π–π interaction. The resulting amino-rich G@PmPD exhibits stable dispersibility and excellent compatibility in organic solvents and polymer matrix. Embedding 0.5 wt% of G@PmPD into the epoxy matrix, and the composite coating can effectively protect the steel substrate for up to 60 d. This superior corrosion resistance is attributed to the impermeability inherited by G@PmPD and the compactness improved by the cross-linking of G@PmPD and EP. Especially in the damaged state, the composite coating embedded with low conductivity G@PmPD triumphantly eliminated graphene’s corrosion-promotion effect. This study provides promising inspiration for the application of graphene in anti-corrosion field.