Electrodeposition of graphene oxide-hydroxyapatite composite coating on titanium substrate

In this work, graphene oxide (GO)/hydroxyapatite (HA) composite coatings were successfully prepared on titanium substrate by electrophoretic deposition technology. Subsequently, microstructure, phase composition, adhesion strength, hydrophilicity, corrosion resistance, bioactivity, antibacterial activity and biocompatibility of the coating were evaluated. The adhesion strength of coating increased by 76% from 6.46 MPa to 17.81 MPa with 0 wt% GO to 12 wt% GO and the corrosion rate of coating with 8 wt% GO was achieved at the minima of (1.493 × 10^-3mm/a). Biomineralization experiment indicated the excellent bioactivity of GO/HA composite coatings. The water contact angle of the composite coatings increased from 20.6°(0 wt% GO) to 38.1°(12 wt%GO). The antibacterial rates of coating with 5 wt% GO was 96.7%, while declined to 25% after thermal treatment. In-vitro L929 cell culture experiments indicated the composite coatings with 5 wt% GO exhibited good biocompatibility.     

Graphene oxide/hydroxyapatite composite coatings fabricated by electrophoretic nanotechnology for biological applications

Graphene oxide (GO) was firstly employed as nanoscale reinforcement fillers in hydroxyapatite (HA) coatings by a cathodic electrophoretic deposition process, and GO/HA coatings were fabricated on pure Ti substrate. The transmission electron microscopy observation and particle size analysis of the suspensions indicated that HA nanoparticles were uniformly decorated on GO sheets, forming a large GO/HA particle group. The addition of GO into HA coatings could reduce the surface cracks and increase the coating adhesion strength from 1.55 ± 0.39 MPa (pure HA) to 2.75 ± 0.38 MPa (2 wt.% GO/HA) and 3.3 ± 0.25 MPa (5 wt.% GO/HA), respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy studies indicated that the GO/HA composite coatings exhibited higher corrosion resistance in comparison with pure HA coatings in simulated body fluid. In addition, superior (around 95% cell viability for 2 wt.% GO/HA) or comparable (80–90% cell viability for 5 wt.% GO/HA) in vitro biocompatibility were observed in comparison with HA coated and uncoated Ti substrate.     

Mechanical properties of warm sprayed HATi bio-ceramic composite coatings

To explore a new approach for fabricating the load bearing implants with the combination of bioactivity, biocompatibility, and mechanical properties, mechanically mixed hydroxyapatite (HA) and titanium (Ti) powders containing 30, 50, and 70 wt% Ti were sprayed onto a 316L stainless steel substrate using a warm spray (WS) process. The microstructures, phase compositions, chemical structures, and mechanical properties of WS HATi composite coatings were comprehensively investigated and compared to those of WS HA coating. Experimental results indicate that the cross-sectional microstructures of WS HATi composite coatings present typical lamellar structures composed of curved stripes formed by well-deformed and oxidized Ti splats and limited deformed HA splats, and are significantly influenced by the Ti content in the original powders. Phase constitutions of the composite coatings mainly consist of HA, Ti, TiO_2, and TiO. Chemical structures of HA in the composite coatings deposited using powders with Ti content less than 30% are similar to the structures in the original powder. The microhardness, elastic modulus, and bond strength of the coatings increased from 0.32 ± 0.15 GPa to 1.41 ± 0.31 GPa, from 1.37 ± 0.28 GPa to 23.28 ± 3.45 GPa, and from 17.3 ± 2.2 MPa to 34.8 ± 3.2 MPa, respectively. The abrasive wear weight loss of the coatings on Al₂O₃ abrasive paper decreased from 2.9 mg to 1 mg, as the addition of Ti particles in original powders increased from 0 to 70%.     

Pulsed electrodeposition of carbon nanotubes-hydroxyapatite nanocomposites for carbon/carbon composites

Carbon nanotubes-hydroxyapatite (CNTs-HA) composite coatings, which behaved like single composites, were synthesized by a combined method composed of electrophoretic deposition and pulsed electrodeposition. The phase compositions and the microstructure of the composite coatings were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FTIR). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies showed that the CNTs-HA composite coatings protected the bare carbon/carbon composites from corrosion in simulated body fluid (SBF) solution. The adhesion strength of CNTs-HA composite coating prepared by the combined method is 14.57±1.06 MPa achieved at the CNTs EPD time of 10 min. Compared to the other CNTs-HA composite coatings with different content of CNTs, the CNT-HA composite coating with the electrophoretic deposition of 10 min showed the best corrosion resistance. The morphology of CNTs-HA composite coatings immersed in SBF solution rendered the formation of HA crystallites. In addition, in vitro cellular responses to the CNTs-HA composite coatings were assessed to investigate the proliferation and morphology of mouse cells 3T3 cell line.     

热处理对钛基体表面电泳沉积GO/HA生物活性涂层的影响

采用电泳沉积法在钛基体表面制备氧化石墨烯(GO)/羟基磷灰石(Ca₁₀(PO₄)₆(OH)₂, HA)复合涂层,通过XRD和SEM等测试手段对不同热处理条件下得到的GO/HA涂层进行表征。研究结果表明,热处理有助于促进涂层中HA结晶度的提高,600℃和800℃的热处理温度并没有导致HA发生热分解,但有可能破坏了涂层中GO的有序晶体结构。GO/HA涂层具有优异的生物活性,但随热处理温度的升高,涂层的润湿性和生物活性下降。热处理过程有利于涂层致密,加强涂层与基体的结合,800℃热处理后的涂层结合强度高达25.31 MPa。     

Microstructure effects on fracture failure mechanism of CrAl/CrAlN coating

In this work, the Metal-rich phase Chromium Aluminum (CrAl)/Ceramic phase Chromium Aluminum Nitride (CrAlN) multi-layer coatings were prepared by Arc Ion Plating (AIP). The micro-structure and phase composition of CrAl/CrAlN multi-layer coatings were characterized, and the microstructure, mechanical properties, residual stress and fracture toughness of the coating were emphatically analyzed. It has been found out that the residual stress of the multi-layer coating was only ?0.932 ± 0.065 GPa, which was significantly lower than that of the mono-layer coating for ?1.569 ± 0.093 GPa. At the same time, it was also found that the preferred growth orientation of the coating changed from a mono-layer (111) to a multi-layer (200) crystal plane. The hardness of the multi-layer (22.74 ± 0.57 GPa) is slightly lower than that of the mono-layer (24.92 ± 0.5 GPa), and the adhesion strength (46.2 ± 3.8 N) is obviously higher than that of the mono-layer (37.4 ± 2.4 N), and the fracture toughness is also higher (8.7 ± 0.8 MPa m^1/2). In addition, the mechanism of crack initiation and propagation in stress-induced coatings was studied in detail on the basis of the structure of micro-nano CrAl/CrAlN multi-layer coatings.     

Hydroxyapatite-carboxymethyl cellulose-graphene composite coating development on AZ31 magnesium alloy: Corrosion behavior and mechanical properties

In this study, hydroxyapatite (HA) coatings containing carboxymethyl cellulose (CMC) and graphene (Gr) were developed on AZ31 magnesium alloy through two-step electrophoretic deposition method. The morphology and chemical bonding of coatings were characterized and also the phase identification was done using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction, respectively. Moreover, the corrosion behavior of the applied coatings was compared with the bare AZ31 Mg alloy substrate in the simulated body fluid by the means of potentiodynamic polarization test and electrochemical impedance spectroscopy. Obtained results revealed that the novel HA-CMC-Gr coating possesses the highest corrosion resistance compared to the HA, HA-CMC, and HA-Gr coatings due to its uniform and compact structure. To investigate the mechanical properties and to elucidate the effect of CMC on the adhesion of coating-alloy interface, pull-off test was employed, where results demonstrated that the addition of CMC increases the adhesion force from 1.06 MPa to 1.62 MPa. Besides, the modulus of elasticity and the hardness of HA and HA-Gr composite coatings were compared by applying nanoindentation test. Interestingly, it is detected that the presence of Gr has considerably increased the elastic modulus of the coating by approximately 30% in comparison to the pure HA coating.     

Fabrication of High Performance PET/TLCP Fibers through the Synergistic Interfacial Enhancement and Compatibilization of Functional 1D and 2D Carbon Nanomaterials

The maleic anhydride functionalized graphene oxide (GO-MA) is fabricated by an efficient and solvent-free Diels–Alder reaction. Polyethylene terephthalate (PET)/thermotropic liquid crystal polyester (TLCP), PET/TLCP/GO-MA, PET/TLCP/aminated multi-walled carbon nanotubes (MWCNTs-NH₂), and PET/TLCP/GO-MA/MWCNTs-NH₂ composite fibers are systematically melt-spun. The structure and compatibilizing effects of GO-MA and MWCNTs-NH₂ on the mechanical, thermal, and crystallization properties of the composite fibers are indicated. The non-isothermal crystallization kinetics and X-ray diffraction (XRD) data show that TLCP and nanofillers can change the crystalline morphology of PET. The mechanical properties of the fibers rise with increasing TLCP content. The tensile strength 929 MPa and modulus 17.5 GPa of the fibers with 7 wt% TLCP and 0.25 wt% nanofillers (0.1 wt% GO-MA and 0.15 wt% MWCNTs-NH₂) are significantly higher than those with 7 wt% TLCP (tensile strength 622 MPa and modulus 16.1 GPa) and even higher than those with 15% TLCP (tensile strength 836 MPa, and modulus 18.0 GPa). When the GO-MA and MWCNTs-NH₂ co-exist, the anti-dripping phenomenon is improved. Therefore, the TLCP, GO, and MWCNTs synergistically strengthens the mechanical properties. This is promising for the industrial fabrication of high-strength fibers.     

Influence of a hard transition layer on the microstructure and properties of diamond-like carbon/hydroxyapatite composite coating prepared by magnetron sputtering

The nanostructured diamond-like carbon/hydroxyapatite composite coating (DLC/HA) was deposited using magnetron sputtering technique with a densely packed columnar cross-sectional structure and a uniform granular surface morphology. After heat treatment, the amorphous structure of the coating was transformed into a crystal structure. Nanohardness and scratch tests results demonstrated the DLC transition layer significantly enhanced the nanohardness of Ti6Al4V substrates from 4.8 GPa to 10.4 GPa, and increased critical load from 16.6 N (pure HA layer) to 26.5 N (DLC layer) without obvious brittle fracture, flaking and delamination. Electrochemical and immersion tests results demonstrated that DLC/HA composite coatings with a dense gradient transition interlayer had better corrosion resistance and could prevent harmful metal ions being released into the SBF solution more effectively than single HA coatings. Furthermore, active Ca²⁺ ions can be rapidly released from the coating surface during initial immersion in the SBF solution, and facilitated the formation of bone-like apatite.     

Grafting of epoxy chains onto graphene oxide for epoxy composites with improved mechanical and thermal properties

Epoxy composites filled with both graphene oxide (GO) and diglycidyl ether of bisphenol-A functionalized GO (DGEBA–f–GO) sheets were prepared at different filler loading levels. The correlations between surface modification, morphology, dispersion/exfoliation and interfacial interaction of sheets and the corresponding mechanical and thermal properties of the composites were systematically investigated. The surface functionalization of DGEBA layer was found to effectively improve the compatibility and dispersion of GO sheets in epoxy matrix. The tensile test indicated that the DGEBA–f–GO/epoxy composites showed higher tensile modulus and strength than either the neat epoxy or the GO/epoxy composites. For epoxy composite with 0.25 wt% DGEBA–f–GO, the tensile modulus and strength increased from 3.15 ± 0.11 to 3.56 ± 0.08 GPa (∼13%) and 52.98 ± 5.82 to 92.94 ± 5.03 MPa (∼75%), respectively, compared to the neat epoxy resin. Furthermore, enhanced quasi-static fracture toughness (K_IC) was measured in case of the surface functionalization. The GO and DGEBA–f–GO at 0.25 wt% loading produced ∼26% and ∼41% improvements in K_IC values of epoxy composites, respectively. Fracture surface analysis revealed improved interfacial interaction between DGEBA–f–GO and matrix. Moreover, increased glass transition temperature and thermal stability of the DGEBA–f–GO/epoxy composites were also observed in the dynamic mechanical properties and thermo-gravimetric analysis compared to those of the GO/epoxy composites.     

A novel biomedical TiN-embedded TiO2 nanotubes composite coating with remarkable mechanical properties,corrosion, tribocorrosion resistance,and antibacterial activity

Tribocorrosion is a severe problem in dental implants, artificial joints, and other implants, and it will affect the long-term safety of the implants. To improve the deficiencies of titanium alloys, we combined physical vapor deposition technology and anodic oxidation to prepare TiN to embed TiO₂ nanotube composite coatings (NTNTs-TiN). Results show that the hardness of the NTNTs-TiN composite coatings reaches 33.2 ± 0.6 GPa, and the grains of the composite coatings were further refined. The NTNTs-TiN coating has the smallest average coefficient of friction (0.22) during tribocorrosion. The tribocorrosion resistance of NTNTs-TiN coating in SBF is increased by ∼44 and ∼2 times compared with Ti6Al4V alloy and TiN coating, respectively. The capillarity effect of the lower contact angle of NTNTs-TiN can form a continuous water-lubrication film at the interface between the counter-ball and coating and produce a lubrication film composed of Ca, Mg, and P, which reduces the coefficient of friction significantly. The NTNTs/TiN composite coating exhibits the best synergistic effect of wear and corrosion. In addition, the NTNTs-TiN coating also exhibits excellent antimicrobial and corrosion properties, which provides a new solution for the long-term safe use of implants in the human body.     

Improvement of Medical Applicability of Hydroxyapatite/Antimonous Oxide/Graphene Oxide Mixed Systems for Biomedical Application

This study supports the binary and ternary merging tactic, this methodology is useful in the creation of new features that lacked in the parent constituents. Ra develops to reach its peak of 4.25 nm upon HAP/Sb₂O₃/GO which is shadowed by HAP/Sb₂O₃ with 3.87 nm. EDX technique offers quantitative, and qualitative elemental composition of the studied composite, where C, O, P, Ca, and Sb elements records 17.14, 66, 8.7, 7.57, and0.58%, respectively. Consequently, the composition is pure. Also, The BET technique’s resultant surface area is 39.49 for HAP/Sb₂O₃, and 50.76 m²/g for HAP/Sb₂O₃/GO. Additionally, The (HAP/GO, and HAP/Sb₂O₃/GO) ceramic composites microhardness was 3.2?±?0.2 GPa for binary composite, and 3.5?±?0.3 GPa for ternary composite. Thus, GO nano-materials enhance mechanical behavior. Applicably, the merging of the three components in one ternary nanocomposite presents the highest viability with 98.4?±?0.8%, besides the highest antibacterial performance by 15.2?±?0.4 mm for Escherichia coli and 16.1?±?0.5 mm for Staphylococcus aureus.

     

Preparation of Tung Oil-Loaded PU/PANI Microcapsules and Synergetic Anti-Corrosion Properties of Self-Healing Epoxy Coatings

Tung oil is used as a catalyst-free repair agent. Tung oil-loaded polyurethane (PU) microcapsules are prepared by interfacial polymerization in a SiO₂-stabilized Pickering emulsion system, polyaniline (PANI) is deposited in situ on the PU microcapsule surface, and tung oil-loaded PU/PANI double-layer shell microcapsules are obtained. Synthesized PU/PANI microcapsules showed the characteristic dark-green color of conductive PANI. The average particle size is 31.1 ± 8.1 µm and the core content is 45.1 ± 4.3 wt%. The microcapsules have a good thermal stability, and the chemical structure of the PU/PANI wall and tung oil core is confirmed by Fourier transform infrared analysis. Self-healing anti-corrosion coatings are prepared by adding 10 wt% microcapsules into epoxy resin. The corrosion resistance properties of the self-healing coating are evaluated by immersing scratched coatings in 10 wt% NaCl solution for 15 days. The self-healing coating with 10 wt% tung oil-loaded PU/PANI microcapsules have the best anti-corrosion property, and slight corrosion do not occur until 15 days after immersion in salt solution. The self-healing and anti-corrosion mechanism are revealed. The tung oil core and the PANI wall of microcapsules contributed synergistically to the excellent self-healing and anti-corrosion properties of the coating through the formation of self-healing films and passivation layers.     

Corrosion behaviour of plasma sprayed graphene nanoplatelets reinforced hydroxyapatite composite coatings in simulated body fluid

Hydroxyapatite (HA) coatings, reinforced with varied concentration (0–2 wt%) of Graphene nanoplatelets (GNPs) have been deposited on titanium alloys (Ti–6Al–4V) substrate using atmospheric plasma spraying. Present work studies the effect of GNP concentration on the electrochemical behaviour of the HA coatings in simulated body fluid (SBF). The HA coating exhibited 15% porosity, whereas reinforcement of 1 wt% GNPs in HA (HA-1G) shows 13% porosity, further addition of 2 wt% GNPs in HA reduced the porosity to 10%. Reduction in porosity was achieved as GNPs easily accessed the inter-lamellae to fill the gaps at inter splat region and minimized the occurrence of post-plasma spray defects such as porosity, voids, microcracks etc. These consequences nextward resulted in the significant enhancement in corrosion resistance of the matrix. HA-1G displayed a significant reduction by 67% in the corrosion rate in SBF solution, while this reduction came to 87% for HA-2G coatings. Randomly oriented wrinkles in the GNPs after corrosion process and their hydrophobic nature effectively hindered the SBF infiltration into the coating and resisted their movement towards the underlying substrate. This in turn improved the overall corrosion resistance of the system.     

Enhancement of mechanical properties of hydroxyapatite coating prepared by electrophoretic deposition method

The addition of bio-inert ceramics such as alumina and zirconia can significantly improve the mechanical properties of hydroxyapatite bioactive coatings and increase their biocompatibility. In the present study, the surface of a titanium substrate was coated by the electrophoretic deposition method (EPD). Moreover, the reaction bonding process has been used to precipitate the nanocomposite containing the hydroxyapatite (HA), alumina, yitteria-stabilized zirconia (YSZ). The coating process was performed by an electrical power supply and a suspension of hydroxyapatite, aluminum, and YSZ nanopowders. For preparing a suspension consisting of 50% isopropanol and 50% acetone, 0.6 g/L of iodine was used as a stabilizer. Green and sintered coatings were analyzed by FE-SEM and XRD. In addition, the mechanical properties such as bonding strength, hardness, and toughness were measured. The hardness, bonding strength, and toughness of the HA coating were 107 ± 10.3 HV, 10.8 ± 3.2MPa, and 0.72MPa√m, respectively, while those of the HA-Al₂O₃-YSZ nanocomposite coating were 213 ± 1.8 HV, 35 ± 1.6MPa, and 1.6MPa√m, respectively.     

Tribological behaviour of RF-magnetron sputter deposited hydroxyapatite coatings in physiological solution

The aim of the paper is to explore the tribological performance of hydroxyapatite (HA) coatings deposited by radio frequency (RF) magnetron sputtering on AZ31 magnesium alloy (96% Mg, 3% Al, 0.7% Zn, 0.3% Mn) for biomedical applications. In this study, the position of the samples on a substrate holder, relative to a target erosion zone was taken into consideration in order to elucidate its impact on the coating characteristics, such as composition, morphology, surface topography and tribology. Substrate rotation and arc-movement were foreseen in the experimental set-up to increase the uniformity of thin film properties. The deposited HA thin films were revealed to exhibit an increase of the Ca/P ratio from 1.83 to 1.97, a decrease of (002) texture and thickness, as the samples were shifted towards the target erosion zone. By coatings, the roughness of Mg alloy was decreased (R_{a Mg alloy}=31.3 nm; R_{a coating}=29 nm and 21 nm). The coating placed in the centre of the substrate holder showed high hardness and Young's modulus (H =8.3±0.9 GPa; E=89±10 GPa) than the coating prepared under the target erosion zone (H =6.9±1.1 GPa; E=75±6 GPa). The coating deposited under target erosion zone exhibits superior friction behaviour in simulated body fluid environment, with the friction coefficient (μ) of 0.184, while the sample located in the centre of the substrate holder possesses the friction coefficient (0.306) comparable to the AZ31 substrate (0.307). The low wear rate was determined in the case of coating deposited under target erosion zone (4.83×10⁻⁵ mm³ N⁻¹ m⁻¹) than uncoated AZ31 substrate (0.00518 mm³ N⁻¹ m⁻¹) or than coating placed in the centre of the substrate holder (0.00294 mm³ N⁻¹ m⁻¹).     

Improving the properties of remanufactured wear parts of shield tunneling machines by novel Fe-based composite coatings

With the aim of remanufacturing high-value wear parts of shield tunneling machines, novel Fe-based composite coatings were prepared by collaborative modification with nano-TiC and nano-CeO₂ particles. This work aims to improve the wear properties of Fe-based alloy coatings by regulating the morphology and dispersion of TiC through the addition of different contents of nano-TiC and nano-CeO₂. First, the coatings with different contents of nano-TiC (from 5 wt% to 15 wt%) and nano-CeO₂ (from 1 wt% to 2 wt%) were prepared by laser cladding. Subsequently, the microstructure, phase composition, microhardness, and wear properties of the coatings were examined. Furthermore, the wear morphology and the influence mechanism of nano-particles on the wear resistance of the coatings were investigated. It was found that the addition of nano-TiC eliminates the macro-defects of Fe55 alloy coating. Meanwhile, the morphology and dispersion of TiC particles in coatings were affected by the content of nano-TiC and nano-CeO₂. Specifically, the addition of 1 wt% nano-CeO₂ facilitates to the formation of near-spherical tiny TiC particles with low agglomeration in the coating. Therefore, the Fe55 + 10 wt% nano-TiC+1 wt% nano-CeO₂ coating exhibits the best wear property among all the prepared Fe-based coatings. This paper provides theoretical guidance for the preparation of the modified Fe-based coating with excellent wear resistance.     

Graphene modified phosphate-based metal/ceramic composite coating for corrosion protection in the high-temperature marine environment

Graphene-modified phosphate-based metal/ceramic composite coatings were prepared for corrosion protection in the high-temperature marine environment. The morphology and structure of the coating were observed by SEM, and the high-temperature anticorrosion performance of the coating was analyzed by electrochemical measurement and salt spray-high temperature cycle test. The results showed that the addition of 0.1 wt% graphene could bridge the aluminum particles inside the composite coating and extend the sacrificial anode protection time of the coating in the 3.5 wt% NaCl solution from less than 4 days to more than 8 days, thus avoiding the local failure of the coating and improving the anticorrosion performance. Besides, the addition of graphene nanosheets at low content also enhanced the physical barrier effect of the coating and prolonged the penetration path of the corrosive medium without destroying the structure of the composite coating.     

Al2O3/Si3N4 nanocomposite coating on aluminum alloy by the anodizing route: Fabrication,characterization, mechanical properties and electrochemical behavior

An Al₂O₃/Si₃N₄ nanocomposite coating was successfully fabricated on commercial aluminum alloy. Hardness measurements, polarization and electrochemical impedance spectroscopy (EIS) were employed to study the mechanical and corrosion behaviors of the coatings. Field-Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) were utilized to characterize the surface morphology and phase composition of the coatings. Also, coatings abrasive wear properties were evaluated with a modified ASTM G105 standard. FE-SEM image, EDS and XRD analysis revealed the presence of Si₃N₄ in the coating. Furthermore, the results showed hardness of the coatings to increase from 380±50 HV for the anodized layer to 712±36 HV for the composite coatings that were formed in an electrolyte containing 6 gr/lit Si₃N₄ nanoparticles. Electrochemical measurements indicated that corrosion resistance of the nanocomposite coating significantly increased compared to the anodized coating. In addition, the effect of Si₃N₄ nanoparticles into the nanocomposite coatings on abrasive wear mechanism and mass loss rate of the coatings was investigated.     

Preparation of polyvinylpyrrolidone/graphene oxide/epoxy resin composite coatings and the study on their anticorrosion performance

Waterborne epoxy resin (EP) is often used as anticorrosive coating in the industrial field. However, small holes and gaps can be formed during the curing process. The corrosive medium easily penetrates the anticorrosive coating and corrodes the metal matrix. Herein, polyvinylpyrrolidone (PVP) and graphene oxide (GO) were doped into EP to improve the shielding and resistance to corrosive media. The composite coatings were prepared successfully by solution blending method. In the PVP/GO composite materials, original spatial structure of GO was changed and the composite was mainly combined by covalent bonding. The surface morphology of hybrid filler was flat and uniform, and the structural defects of GO was reduced. Compared with single-layer anticorrosive coating, the corrosion potential of PVP/GO/EP coating moved forward and the corrosion current density decreased. The ideal corrosion resistance of PVP/GO/EP composite coatings was mainly because agglomeration of GO sheet was obviously avoided after it was modified by PVP. Furthermore, the hybrid filler can be uniformly dispersed in the aqueous EP. It blocked the gaps and holes inside the coatings, which could contribute to form anticorrosive coatings.