Epoxy coating with self-healing capability based on a 2-mercaptobenzothiazole-loaded CeO2 nanocontainer

In this study, we demonstrated a facile approach for the synthesis of nanocontainers using the encapsulation of a 2-mercaptobenzothiazole (MBT) inhibitor; these nanocontainers were capable of responsively releasing a corrosion inhibitor and of self-healing performances. The anticorrosive performance of the CeO₂ nanocontainers was investigated with electrochemical impedance spectroscopy (EIS) measurement in a saline electrolyte via the incorporation of different weight percentages (0.5, 1, and 2 wt %) of synthesized nanocontainer in epoxy (EP) resin. The EIS results show that the loading of 1 wt % CeO₂ nanocontainer containing MBT inhibitor in the epoxy (EP) coating [EP/NC MBT–CeO₂ (1%)] provided the highest R_coat, the lowest constant phase element of coating, and the optimum release of MBT at different operating pHs. The highest coating resistance R_coat values of this coating (7.81 × 10⁷ Ω cm²) were about 12 and 8573 times greater than those considered for EP–CeO₂ and EP coatings, respectively. Different releases of the MBT inhibitor were detected at various pHs. We found that the coating operating in acidic media exhibited a better self-healing performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47297.     

Synergic enhancement of the anticorrosion properties of an epoxy coating by compositing with both graphene and halloysite nanotubes

The aim of this research was to improve the corrosion resistance of metal surfaces with polymer coatings. Both graphene and halloysite nanotubes (HNTs) were introduced together into the epoxy resin coating for the enhanced barrier protection of the metallic surface. The anticorrosion behaviors of different coatings were comparatively evaluated by the potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. The potentiodynamic polarization curves showed that the coating containing 0.5 wt % HNTs and 0.8 wt % graphene (H05G08EP) together had the most positive corrosion potential and the minimum corrosion current density. The EIS results revealed that graphene endowed the composite coatings with excellent electrochemical performance for anticorrosive purposes. The NSS tests indicated that H05G08EP endured the longest NSS time. These results suggest that H05G08EP had the best corrosion resistance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47562.     

Incorporation of silica network and modified graphene oxide into epoxy resin for improving thermal and anticorrosion properties

In this study, the silica network and functionalized graphene oxide (GO) were incorporated into the epoxy coating systems, which was aimed to improve the thermal property and corrosion resistance of epoxy coatings. First, tetraethyl orthosilicate (TEOS) oligomers and epoxy hybrid was fabricated through sol–gel method. Then the (3-aminopropyl) triethoxysilane (APTES) modified graphene oxide (FGO) was added into the epoxy hybrid composite to obtain anticorrosion coatings. Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectrum, and X-ray photoelectron spectrum were conducted to evaluate the structural information of GO and APTES modified GO nanosheets. The results indicated that the APTES successfully grafted onto the surface of GO sheets. Besides, TGA curves, electrochemical measurements and salt spray test were also carried out to characterize the thermal performance and corrosion resistance of GO based epoxy coatings. The TGA results revealed that the thermal performance of epoxy coating containing silica network and FGO nanofiller (ES/FGO) was significantly strengthened compared to pure epoxy. The initial degradation temperature of epoxy coating was increased from 300 to 343.7°C after incorporation of silica component and FGO. The EIS measurements demonstrated that the impedance modulus of ES/FGO was significantly higher than neat epoxy, which indicated that the corrosion resistance of epoxy was substantially strengthened after introduction of silica component and FGO. The corrosion rate and inhibition efficiency of epoxy composite coatings were also shifted from 1.237 × 10⁻⁷ mm/year and 76.6% (for neat epoxy) to 1.870 × 10⁻⁹ mm/year and 99.6% (for ES/FGO), respectively. The salt spray test also revealed that the silica and FGO can improve the corrosion resistance of epoxy coating. Additionally, the dispersion of GO sheets was also enhanced after the modification of APTES siloxane.     

利用EIS高频区参数评价两种环氧涂层的性能

利用10 kHz下的相位角、10 kHz下的相对介电常数和对应于45°相位角的特征频率这3种EIS高频区的参数对两种环氧涂层体系在盐水浸泡+紫外照射的腐蚀条件下的失效过程进行了表征,并与涂层阻抗值进行了对比。测量结果表明,上述3种高频区参数的结果一致,都能够反映涂层性能的变化及相对优劣。当频率10 kHz处的相位角下降到40°,相对介电常数增大到40,或特征频率接近10 kHz时,所研究的两种环氧涂层体系的阻抗值都对应降低到10⁶ Ω•cm²左右,涂层保护性能接近失效。由于这几种EIS高频区参数能够很快测得,因此可以利用这些参数快速评价该涂层的保护性能与失效程度。     

Tribological and corrosion behaviors of fluorocarbon coating reinforced with sodium iron titanate platelets and whiskers

A series of sodium iron titanate (NFTO)–fluorocarbon composite coatings have been prepared with the liquid-phase blending method. The effects of two types of NFTO, NFTO platelets, and NFTO whiskers, on the tribological and corrosion behaviors of the composite coatings, are systematically studied. The results show that the addition of NFTO can significantly enhance the friction-reducing and wear resistance performances of the fluorocarbon coating. Under dry sliding, the minimum specific wear rate is 1.67 × 10⁻⁴ mm³/Nm for the platelet-filled composite coatings and 1.15 × 10⁻⁴ mm³/Nm for the whisker-filled composite coatings, respectively, showing a decrease of 83.5 and 88.6% than that of pure coating. Under a simulated seawater environment, the minimum specific wear rate is 5.44 × 10⁻⁵ mm³/Nm for the platelet-filled composite coatings and 0.84 × 10⁻⁵ mm³/Nm for the whisker-filled composite coatings, respectively, showing a decrease of 90.5 and 98.5% than that of pure coating. The morphologies of worn surfaces, wear debris, and transfer films are analyzed, and the corresponding wear resistance mechanisms are discussed. The electrochemical impedance spectroscopy certifies a remarkably improved corrosion resistance of the composite coatings which have been immersed in 3.5 wt % NaCl solution for 30 days. The composite coating reinforced with 7.5 wt % platelets shows the highest resistance of 256.3 × 10⁶ Ω·cm², approximately two orders of magnitude higher than that of pure coating. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48936.     

PANI-chitosan-TiO2 ternary nanocomposite and its effectiveness on antibacterial and antistatic behavior of epoxy coating

A straightforward approach has been developed for fabricating antibacterial and antistatic epoxy coatings by using polyaniline-chitosan modified TiO₂ ternary nanocomposite. This nanocomposite was synthesized through the following steps. First, chitosan was grafted onto the TiO₂ nanoparticles and then final nanocomposite was prepared via solution polymerization of aniline. Electrical conductivity measurement revealed that nanocomposite with 7.5 wt % of the modified TiO₂ nanoparticles has noticeably higher conductivity compared to polyaniline. Evaluating the coatings' antibacterial property indicated epoxy coatings with the content of ternary nanocomposite show significant bactericidal activity against Gram-positive bacteria and have acceptable antibacterial action against Gram-negative ones. Also, obtained results showed that the ternary nanocomposite would greatly decrease coatings' surface resistivity and when nanocomposite content is about 2 wt % surface resistivity is about 3 × 10⁷ Ω sq⁻¹. On the contrary, the coating with nanocomposite loading exhibits improved thermal and mechanical performance compared to the coating made of neat epoxy. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47629.     

Excellent corrosion protection performance of epoxy composite coatings filled with silane functionalized silicon nitride

Silicon nitride was firstly used as anticorrosive pigment in organic coatings. An effective strategy by combining inorganic fillers and organosilanes was used to enhance the dispersibility of silicon nitride in epoxy resin. The formed nanocomposites were applied to protect Q235 carbon steel from corrosion. The anticorrosive performance of modified silicon nitride with silane (KH-570) was investigated by electrochemical impedance spectroscopy (EIS), water absorption and pull-off adhesion methods. With the increase of immersion time, the corrosion resistance as well as adhesion strength of epoxy resin coating and unmodified silicon nitride coating decreased significantly. However, for the modified silicon nitride coating, the corrosion resistance and adhesion strength still maintained 5.7×10¹⁰ Ω cm² and 7.6 MPa after 2400-h and 1200-h immersion, respectively. The excellent corrosion resistance performance could be attributed to the chemical interactions between KH-570 functional groups and silicon nitride powders, which mainly came from the easy formation of Si-O-Si bonds. Furthermore, the modified silicon nitride coating formed a strong barrier to corrosive electrolyte due to the hydrophobic of modified silicon nitride powder and increased bonds.     

咪唑啉季铵盐缓蚀剂改性蒙脱土/水性环氧纳米复合涂料

以油酸、二乙烯三胺和氯化苄为原料,合成了油酸基咪唑啉季铵盐缓蚀剂。通过FTIR、¹HNMR对其结构进行了表征,并离子交换至钠基蒙脱土(DK0)层间,制备了缓蚀剂改性蒙脱土(QACDK0)。通过XRD、TGA和UV-Vis对其结构、组成及层间缓蚀剂释放性能进行了表征。结果表明,咪唑啉季铵盐缓蚀剂约占QACDK0质量的38.96%,并将蒙脱土层间距由1.28 nm(DK0)扩大至3.98 nm(QACDK0)。利用DLS及Zeta电位对添加有QACDK0的水性环氧树脂进行了稳定性测试,其Zeta电位为–27.8 m V,具有较高的稳定性。电化学阻抗谱(EIS)测试表明,在腐蚀介质中浸泡30 d后,基于QACDK0制备的清漆漆膜仍具有2.29×10⁸?·cm²的高阻抗,表明涂层具有较好的耐腐蚀性。并且在耐中性盐雾测试中,QACDK0对应的防腐色漆耐盐雾时间最长,验证了该涂层具有良好的耐盐雾性能。     

Corrosion performance of waterborne epoxy coatings containing polyethylenimine treated mesoporous-TiO2 nanoparticles on mild steel

Waterborne epoxy coatings were modified by adding mesoporous-TiO₂ nanoparticles (meso-TiO₂). In order to achieve proper dispersion of meso-TiO₂ in the epoxy-based coating and make possible chemical interactions between meso-TiO₂ and polymeric coating, meso-TiO₂ was treated with polyethylenimine (PEI) of various molecular weights. Corrosion performance of mild steel coated specimens was investigated employing electrochemical impedance spectroscopy (EIS) and salt spray test. Coatings with meso-TiO₂/PEI (600 molecular weight) possessed the best corrosion performance among the coating specimens. The EIS results showed that the resistance value of coating with meso-TiO₂/PEI (600 molecular weight) was above 9.87 × 10⁷ Ω cm² which was higher than neat epoxy coating. Possible chemical interactions between polymeric matrix and treated nanoparticles caused high barrier properties and high degree of cross-linking.     

Enhancement of Corrosion Performance of Epoxy Coatings by Chemical Modification With GPTMS Silane Monomer

In this paper, commercial epoxy resin was chemically modified by different amounts of 3-glycidoxypropyltrimethoxysilane (GPTMS) monomer using an organotin compound as catalyst, aiming to improve the anti-corrosion performance of epoxy coatings on 2024-T3 aluminum alloy substrate. Electrochemical impedance spectroscopy (EIS) was used to evaluate the barrier properties against water permeation and protectiveness of silane-modified epoxy coatings. The results showed that all the modified coatings presented higher barrier performance and better corrosion performance than pure epoxy coating, which were characterized by higher charge transfer resistance (R _ct) and lower double-layer capacitance (C _dl) at the electrolyte/metal interface. The improvements in corrosion performance and wet adhesion of modified epoxy coatings were also observed by the Machu test and boiling water test, respectively. Interestingly, it was found that the glass-transition temperature (T _g) of silane-modified epoxy coatings decreased only slightly during immersion in 3.5 wt% NaCl solution, in contrast with pure epoxy coating, which was observed to decrease significantly after water permeation. The corrosion performance of epoxy coatings was, thus, improved when the amount of chemically grafted silane monomer increased in the content range investigated in the present work.     

无机/有机复合涂层体系在3.5%NaCl溶液中的EIS

采用电化学阻抗谱（EIS）研究了无机富锌底漆/环氧云铁中间漆/氯化橡胶面漆复合涂层体系在3.5%NaCl溶液中的腐蚀电化学行为,考察了紫外辐射对其电化学行为的影响。结果表明：复合涂层体系在3.5%NaCl介质中的腐蚀失效过程可以用4种等效电路来等效。浸泡失效前120 h,电解质溶液电阻R_c从开始的5×10⁹ Ω·cm²以大约2.2×10⁷ Ω·h^-1的速度迅速下降到4×10⁵ Ω·cm²,到浸泡120 h后R_c则以较小的速度808 Ω·h^-1下降,涂层电容C_c是按线性增加。紫外辐射不改变复合涂层体系在3.5% NaCl溶液中的电化学行为,仅仅加速复合涂层的失效。     

Innovative conductive polymer composite coating for aircrafts lightning strike protection

A new kind of high electrical conductive epoxy coating with low filler rate was investigated for lightning strike protection (LSP) of carbon fiber reinforced polymer (CFRP). The coating without CFRP substrate was firstly studied. The influence of silver submicronic wires (AgSWs) with a high aspect ratio on the electrical behavior is observed; that is, the electrical resistivity evolution, the current density value, and the electrical conduction mechanisms as function of temperature. The preponderant electrical conduction mechanism is an Ohmic behavior. The higher level of conductivity obtained is 5.5 × 10⁵ S m⁻¹ for 9% vol of AgSWs. Lightning strike tests were carried out on an epoxy/AgSWs coating filled with 8% in volume (74 gsm) and deposited on a CFRP. The ultrasonic testing after lightning strike on coated CFRP shows no structural delamination and demonstrates the interest of this new route for an efficient LSP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48700.     

Polymers based on N,N‐diglycidylaniline. I. Investigations of the curing kinetics by dynamic differential scanning calorimetry measurements

N,N‐Diglycidylaniline was reacted with aniline (yielding polymer EP‐1) and the newly synthesized chromophore 4‐(phenylazo)aniline (yielding polymer EP‐2). The curing kinetics of these two epoxy resin systems was studied in dynamic experiments by means of differential scanning calorimetry. Kinetic parameters such as the activation energy and frequency factor were estimated with the Ozawa method [E(O) and A(O), respectively], the Kissinger method [E(K) and A(K), respectively], and the modified Avrami method [E(A) and A(A), respectively]. The activation energy and frequency factor of EP‐1 were much lower than those of EP‐2 estimated with the Ozawa, Kissinger, and Avrami methods. The activation energy and frequency factor for EP‐1 determined with the Ozawa method [E(O) = 55.8 kJ/mol, A(O) = 10 × 10³ 1/s] and the Avrami method [E(A) = 56.4 kJ/mol, A(A) = 9.2 × 10³ 1/s] were higher than those determined with the Kissinger method [E(K) = 51.0 kJ/mol, A(K) = 2 × 10³ 1/s]. In the case of EP‐2, the kinetic parameters calculated with the Ozawa model [E(O) = 140.4 kJ/mol, A(O) = 12.3 × 10¹³ 1/s] and the Kissinger model [E(K) = 139.9 kJ/mol, A(K) = 10.9 × 10¹³ 1/s] were higher than those calculated with the Avrami model [E(A) = 130.4 kJ/mol, A(A) = 7.9 × 10¹² 1/s]. The obtained polymers were characterized with Fourier transform infrared, ¹H‐NMR, differential scanning calorimetry, and ultraviolet–visible spectroscopy. The polymers exhibited low glass‐transition temperatures in the range of 57–79°C and good solubility in common organic solvents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and anticorrosion resistance of a self-curing epoxy nanocomposite coating based on mesoporous silica nanoparticles loaded with perfluorooctyl triethoxysilane

Organic coatings are prone to failure due to diffusion of the corrosion media toward the metal surface through the microcracks caused by internal and environmental stresses especially in immersion environment. In order to extend the service lifetime of organic coatings, we developed a self-curing epoxy resin/perfluorooctyl triethoxysilane (POTS)-loaded mesoporous silica nanoparticles (MSNs) nanocomposite (SEP/POTS-MSNs) coating, by embedding the POTS-loaded MSNs (POTS-MSNs) into an SEP resin. Fourier transform infrared, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analyses were conducted to confirm the successful loading of POTS in the MSNs. Thermogravimetric analysis was used to characterize the loading amount of POTS. The corrosion protection properties of the SEP, SEP/MSNs, and SEP/POTS-MSNs coatings were evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests. The results indicate that the SEP/POTS-MSNs coating with only 30 μm thickness showed corrosion resistance with Z _{f = 0.01 Hz} of 4.7 × 10⁸ Ω/cm² and i_corr of 0.026 nA/cm² after 58 hr of immersion in boiling water, which were both two orders of magnitude higher than those of the SEP coating. The SEP/POTS-MSNs coating combines the advantages of the SEP coating and the POTS-MSNs. We anticipate that the SEP/POTS-MSNs coating has promising potential for use in immersion environments.     

Atomic force microscopy analysis of cathodic arc ion-plated CrN and CrC coatings

Coatings of CrN and CrC were deposited on a YT14 cemented carbide cutting tool using cathodic arc ion plating (CAIP). The surface and interface morphologies of the as-obtained CrN and CrC coatings were analyzed using a field emission scanning electron microscope. The heights, particle diameters and power spectral densities of CrN and CrC coatings were analyzed using atomic force microscopy and the correlated parameters of roughness were obtained. The results show that the roughness of the CrN and CrC coatings is 81.7 × 10^?3 and 70.2 × 10^?3 nm, respectively, and CAIP has little effect on the CrN and CrC coating roughness. The height of the peak values of CrN and CrC coatings is 0.498 and 0.502 nm, respectively, and the reduction friction of the CrN coating was slightly better than that of the CrC coating. The average particle diameter of the CrN and CrC coatings is 6.575 × 10² and 7.678 × 10² nm, respectively, and the particles are uniformly distributed with no large-scale fluctuations. The power between the cursors of the CrN and CrC coatings is 1.44 × 10^?2 and 9 × 10^?3 nm², respectively, with the power spectral density of the CrN coating being the dominant frequency.     

Investigation of the thermomechanical properties of a plasma-sprayed nanostructured zirconia coating

Yttria partially stabilized nanostructured zirconia coatings were deposited by atmospherical plasma spraying (APS). The microstructure of the as-sprayed nanostructured coating was characterized with Scanning electronic microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrum (RS). The laser-flash diffusivity method and push-rod method were used to examine the thermomechanical properties of the nanostructured zirconia coatings. The results obtained indicated that the plasma-sprayed zirconia coating possessed nano-structure and its average grain size was about 73 nm. The average thermal expansion coefficients of the nanostructured coating at the first thermal cycle and second thermal cycle from room temperature to 1200 °C are 11.0 and 11.6×10⁻⁶ °C⁻¹, respectively. The thermal diffusivity of the nanostructured zirconia coating was 1.80–2.54×10⁻³ cm²/s between 200 and 1200 °C. The microhardness of the nanostructured zirconia coating was 8.6 GPa, which was 1.6 times as large as that of traditional zirconia coating.     

Synthesis and characterization of fluorinated poly(etherimide)s toughening for carbon fiber‐reinforced epoxy composites

Novel‐fluorinated poly(etherimide)s (FPEIs) with controlled molecular weights were synthesized and characterized, which were used to toughen epoxy resins (EP/FPEI) and carbon fiber‐reinforced epoxy composites (CF/EP/FPEI). Experimental results indicated that the FPEIs possessed outstanding solubility, thermal, and mechanical properties. The thermally cured EP/FPEI resin showed obviously improved toughness with impact strength of 21.1 kJ/m² and elongation at break of 4.6%, respectively. The EP/FPEI resin also showed outstanding mechanical strength with tensile strength of 91.5 MPa and flexural strength of 141.5 MPa, respectively. The mechanical moduli and thermal property of epoxy resins were not affected by blending with FPEIs. Furthermore, CF/EP/FPEI composite exhibited significantly improved toughness with Mode I interlaminar fracture toughness (G_IC) of 899.4 J/m² and Mode II interlaminar fracture toughness (G_IIC) of 1017.8 J/m², respectively. Flexural properties and interlaminar shear strength of the composite were slightly increased after toughening. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Thermal conductivity and electromagnetic shielding effectiveness of composites based on Ag‐plating carbon fiber and epoxy

Thermally conductive and electromagnetic interference shielding composites comprising low content of Ag‐plating carbon fiber (APCF) were fabricated as electronic packing materials. APCF as conductive filler consisting of carbon fiber (CF) employed as the structural component to reinforce the mechanical strength, and Ag enhancing electrical conductivity, was prepared by advanced electroless Ag‐plating processing on CF surfaces. Ag coating had a thickness of 450 nm without oxide phase detected. The incorporation of 4.5 wt % APCF into epoxy (EP) substrate yielded thermal conductivity of 2.33 W/m·K, which is approximately 2.6 times higher than CF–EP composite at the same loading. The APCF–EP composite performed electromagnetic shielding effectiveness of 38–35 dB at frequency ranging from 8.2 to 12.4 GHz in the X band, and electromagnetic reflection was the dominant shielding mechanism. At loading content of APCF up to 7 wt %, thermal conductivity of APCF–EP composites increased to 2.49 W/m·K. Volume resistivity and surface resistivity decreased to 9.5 × 10³ Ω·cm and 6.2 × 10² Ω, respectively, which approached a metal. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42306.     

Effect of poly(etherimide) chemical structures on the properties of epoxy/poly(etherimide) blends and their carbon fiber‐reinforced composites

Poly(etherimide)s (PEIs) with different chemical structures were synthesized and characterized, which were employed to toughen epoxy resins (EP/PEI) and carbon fiber‐reinforced epoxy composites (CF/EP/PEI). Experimental results revealed that the introduction of the fluorinated groups and meta linkages could help to improve the melt processability of EP/PEI resins. The EP/PEI resins showed obviously improved mechanical properties including tensile strength of 89.2 MPa, elongation at break of 4.7% and flexural strength of 144.2 MPa, and good thermal properties including glass transition temperature (T_g) of 211°C and initial decomposition temperature (T_d) of 366°C. Moreover, CF/EP/PEI‐1 and CF/EP/PEI‐4 composites showed significantly improved toughness with impact toughness of 13.8 and 15.5 J/cm², respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Epoxy/polyaniline–ZnO nanorods hybrid nanocomposite coatings: Synthesis,characterization and corrosion protection performance of conducting paints

The objective of this research is the production of an epoxy coating blended with organic–inorganic hybrid nanocomposite as a corrosion inhibiting pigment applied over carbon steel grade ST37. A series of conducting polyaniline (PANI)–ZnO nanocomposites materials has been successfully prepared by an in situ chemical oxidative method of aniline monomers in the presence of ZnO nanorods with camphorsulfonic acid (CSA) and ammonium peroxydisulfate (APS) as surfactant and initiator, respectively. The synthesized polymers were characterized by X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA) and electrical conductivity techniques. Synthesized nanocomposites were solved in tetraethylenpentamine (TEPA), and then prepared solution was mixed with epoxy and then was applied as a protective coating on carbon steel plates. The anti-corrosion behavior of the epoxy binder blended with PANI–ZnO nanocomposites were studied in 3.5% NaCl solution at a temperature of 25 °C by electrochemical techniques including electrochemical impedance spectroscopy (EIS) and chronopotentiometry at open circuit potential (OCP). It was observed that the epoxy coating containing conducting PANI–ZnO nanocomposites exhibited higher corrosion resistance and provided better barrier properties in the paint film in comparison with pure epoxy and epoxy/PANI coatings. In the case of conducting coatings, the OCP was shifted to the noble region due to presence of PANI pigments. Additionally, the possibility of formation of a passive film in the presence of PANI was reinforced at the substrate–coating interface. SEM studies taken from surface of the coatings showed that epoxy/PANI–ZnO hybrid nanocomposite coating systems (EPZ) are crack free, uniform and compact. Furthermore, it was found that the presence of ZnO nanorods beside PANI can significantly improve the barrier and corrosion protection performance of the epoxy coating due to the flaky shaped structure of the PANI–ZnO nanocomposites.