It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is sti...It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is still a challenge because of the common complex design and synthesis. Herein, the bio-based monomer protocatechuic acid(PCA) was used as raw material, the catechol structure with high bonding and antibacterial properties was introduced into the flexible alkane segment of ethylene glycol diglycidyl ether(EGDE) through an efficient, and green method, and it was cured with isophorone diamine(IPDA) to prepare corresponding thermosets. The cured resins exhibited excellent allaround qualities, particularly in bonding and antibacterial. When 30% PCA was added to pure epoxy resin, the adhesion between substrate and coating increased from 4.40 MPa to 13.60 MPa and the antibacterial rate of coating against E. coli and S. aureus could approach 100%. All of this is due to the fact that the catechol structure present in PCA has the ability to interact with various substrates and alter the permeability of bacterial cell membranes. The architecture of this method offers a fresh approach to dealing with the issues of challenging raw material selection and complex synthesis techniques.展开更多
The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification proc...The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient protection.In the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly technique.The outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)film.The FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier capability.The Ce film connects the outer layer with the substrate,showing the transition effect.The corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling behavior.The synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.展开更多
Two-dimensional Ti_(3)C_(2)T_(x) flakes have great application potential in various areas due to their optical,electronic,electrochemical and mechanical properties,but their anti-corrosion and wear-resistance performa...Two-dimensional Ti_(3)C_(2)T_(x) flakes have great application potential in various areas due to their optical,electronic,electrochemical and mechanical properties,but their anti-corrosion and wear-resistance performance were not well understood.The difficulties in achieving good dispersity and interface interaction of inorganic additives in organic coatings hinder the incorporation of Ti_(3)C_(2)T_(x) into the epoxy coating.Here,few-layered Ti_(3)C_(2)T_(x) sheets with amino-functionalization were prepared,and as reinforced-additives were added into the waterborne epoxy coating.Anti-corrosion and tribological properties of as-prepared composite coatings were investigated in detail.The results reveal that the composite coating with 0.5 wt.%amino-functionalized Ti_(3)C_(2)T_(x) sheets shows excellent corrosion protection(the lowest frequency impedance was 3.12×10^(9) cm^(2))and wear resistance(wear rate was reduced by 72.74%).The greatly improving performance of composite coatings mainly depends on:(a)good dispersity and compatibility of amino-functionalized Ti_(3)C_(2)T_(x) in organic matrix,(b)high adhesion strength between coating and metal substrate and(c)the intrinsic properties of Ti3C2Tx sheets.The work provides a good path for applications of MXene as multifunctional additives.展开更多
The surface of ZrO2 nanoparticles was modified by styrene coupling grafting method to improve the dispersion and interaction of the nanoparticles with the epoxy coating in which the modified ZrO2 nanoparticles were us...The surface of ZrO2 nanoparticles was modified by styrene coupling grafting method to improve the dispersion and interaction of the nanoparticles with the epoxy coating in which the modified ZrO2 nanoparticles were used as an additive. The grafting performance and microstructure of the nano- ZrO2/epoxy coating were analyzed by Fourier transformation infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The corrosion behavior of the nano-ZrO2/epoxy coating on mild steel was evaluated in neutral 3.5 wt% NaC1 solution using electrochemical impedance spectroscopy （EIS）. Both the coating capacitance and coating resistance fitted by the equivalent circuit from EIS were used to evaluate the protective performance of the coating towards the mild steel. The results show a superior stability and efficient corrosion protection by the modified ZrO2 nanoparticles. The epoxy coating containing 2 wt% modified ZrO2 nanoparticles exhibited the best corrosion performance among all the coating specimens. This research may provide an insight into the protection of mild steel using modified epoxy coatings.展开更多
Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy（EIS）...Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy（EIS） and immersion test. Open circuit potential（OCP） measurements and immersion tests were also carried out to better understand the behavior of zinc rich coating. EIS and OCP measurements showed that addition of 1 wt% clay improved the cathodic protection duration and sacrificial properties of the epoxy zinc rich coating. Transmission electron microscopy（TEM） photographs confirmed that clay nanoparticles were successfully dispersed in the coating matrix loaded with 1 wt% clay. Immersion test results indicated that addition of 1 wt% clay nanoparticles in zinc rich epoxy coatings increased the cathodic protection ability of coatings.展开更多
The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe operation.In this work,we presented a method to protect the rusted steel by ru st conversion tre...The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe operation.In this work,we presented a method to protect the rusted steel by ru st conversion treatment and epoxy coating.Tannic acid was selected as rust conversion agent.Tannic acid,D-limonene and nano-ZrO_(2)were used to improve the corrosion resistance of epoxy coatings.The Raman spectra,Xray diffraction and 3 D confocal images were used to characterize the rust conversion reaction.Ad hesion test showed that the loss of wet adhesion of the optimal coating was relatively low due to the addition of tannic acid,limonene and nano-ZrO(2).The corrosion resistance of five different coatings was investigated by scanning electron microscopy(SEM)and electrochemical analysis.Results show that after 264 h acid immersion,the low frequency resistance of the optimal coating consisting of rust conversion treatment and additives is 10^(7)Ωcm^(2),three orders magnitude higher than that of the pristine coating.Moreover,SEM indicates that the optimal coating possesses a smooth surface and an unbroken interface between substrate and coating.Accordingly,the corrosion-resistant mechanism of the hybrid coating is proposed.展开更多
A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphol...A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution.展开更多
Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings dis...Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings displayed outstanding barrier properties against H20 molecule compared to the neat epoxy coating. Open circuit potential （OCP）, Tafel and electrochemical impedance spectroscopy （EIS） analysis confirmed that the corrosion rate exhibited by composite coatings with 0.5 wt% G was an order of magnitude lower than that of neat epoxy coating. Salt spray test results revealed superior corrosion resistance offered by the composite coating.展开更多
A facile and environmentally-friendly method is developed to prepare graphene/waterborne epoxy(WEP)composite coatings.The graphene nanosheets are produced with electrochemical-exfoliation in the solution containing su...A facile and environmentally-friendly method is developed to prepare graphene/waterborne epoxy(WEP)composite coatings.The graphene nanosheets are produced with electrochemical-exfoliation in the solution containing surfactants,cetyl trimethyl ammonium bromide(CTAB)and sodium dodecyl sulfate(SDS).The nanosheets containing solution thus formed are subjected to a quick dialysis and then directly used as a diluent for WEP without any further treatment.This preparation method overcomes the commonly identified problems of aggregations and‘corrosion promotion’effect associated with graphene,and increases the impedance of the composite coatings by more than two orders of magnitude.The analysis of anticorrosion performance suggested that the presence of surfactants not only improves the dispersibility of graphene nanosheets but also endows the composite coatings with both barrier and corrosion inhibition capabilities.The strategy reported herein may pave the path to the large-scale production of graphene anticorrosion coatings.展开更多
Based on a two-dimensional(2D)Co-MOF(Co_(2)(OH)_(2)BDC)with a self-contained organic interface and low conductivity,a composite epoxy coating(2D Co_(2)(OH)_(2)BDC-PAN/EP)was constructed by a two-step preparation.First...Based on a two-dimensional(2D)Co-MOF(Co_(2)(OH)_(2)BDC)with a self-contained organic interface and low conductivity,a composite epoxy coating(2D Co_(2)(OH)_(2)BDC-PAN/EP)was constructed by a two-step preparation.First,a polyacrylonitrile(PAN)nanofiber membrane was electrospuned on the surface of Q235 steel,followed by coating using the epoxy coating(EP)containing 2D Co_(2)(OH)_(2)BDC.The 2D Co_(2)(OH)_(2)BDC-PAN/EP composite epoxy coatings showed robust mechanical performance and excellent corrosion resistance capacity.展开更多
This paper presents the results regarding the effect of nano aluminum powder pigment concentration on the protective properties of waterborne epoxy films in 3.5 wt pct NaCl solution. The anticorrosive performance of t...This paper presents the results regarding the effect of nano aluminum powder pigment concentration on the protective properties of waterborne epoxy films in 3.5 wt pct NaCl solution. The anticorrosive performance of the coatings with 0.5, 1, and 3 wt pct pigments and none pigment were investigated using electrochemical impedance spectroscopy （EIS）, scanning electron microscopy （SEM） and Raman spectroscopy techniques. The results show that adding appropriate amount of nano-aluminium powder pigment can enhance the barrier properties of the epoxy coating, which is attributed to the surface effect of nanoparticles and the compatibility of the pigment with the waterborne epoxy coatings.展开更多
Introducing inorganic nanomaterials into a polymer matrix greatly improves the anticorrosion performance of epoxy coatings(EP);however,poor compatibility between the materials can limit the improvement in properties.I...Introducing inorganic nanomaterials into a polymer matrix greatly improves the anticorrosion performance of epoxy coatings(EP);however,poor compatibility between the materials can limit the improvement in properties.In this work,based on the high interface compatibility of two-dimensional(2D)Co_(2)(OH)_(2)BDC(BDC=1,4-benzenedicarboxylate)in the epoxy coating that we reported in previous work,we fabricated a 2D Co_(2)(OH)_(2)BDC-halloysite nanotube(HNT)nanocomposite have a structure consisting of alternating of nanosheets and nanotube by in situ synthesis.The nanocomposite was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,and scanning electron microscopy.The mechanical and anticorrosion performance of the 2D Co_(2)(OH)_(2)BDC-HNT/EP coating was evaluated by mechanical tests and electrochemical impedance spectroscopy spectra.Compared with a conventional unreinforced epoxy coating,the 2D Co_(2)(OH)_(2)BDC-HNT/EP coating had higher mechanical strength and toughness,and the low-frequency impedance modulus of 2D Co_(2)(OH)_(2)BDC-HNT/EP coating was increased by three orders of magnitude,demonstrating the high corrosion resistance of our reinforced coating.展开更多
The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy si...The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals,and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5%NaCl solution.The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion,synergistic protection,and substrate damage.Besides,Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating.This organic monolayer coating,in conjunction with the synergistic inorganic conversion layer comprising Al_(2)O_(3),TiO_(2),2H_(2)O,ZrO_(2),2H_(2)O,effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.展开更多
Combining conventional waterborne epoxy coatings(WEP)with specific functionalities is essential to increase their service life.However,designing multifunctional protective coatings with tunable interfaces to improve t...Combining conventional waterborne epoxy coatings(WEP)with specific functionalities is essential to increase their service life.However,designing multifunctional protective coatings with tunable interfaces to improve their corrosion and weather resistance remains challenging.In this study,based on intermolecular forces between quaternized lignosulfonate(QLS)and tertbutyl titanate,we prepared QLS-TiO_(2)nanocomposite with structural regularity and strong chemical bonding by a simple one-pot method.It was further used for doped modified WEP to prepare a high-performance QLS-TiO_(2)/WEP coating.The results showed that QLS-TiO_(2)can effectively scavenge radicals,absorb and reflect strong ultraviolet rays,and exhibit high dispersibility and interfacial compatibility in the epoxy matrix.Consequently,QLS-TiO_(2)/WEP coating demonstrated excellent weathering resistance,with the polymer chain segments within the coatings remaining intact after 240 h of accelerated aging test.Furthermore,QLS-TiO_(2)exhibited chemical stability and impressive anti-corrosion properties.Its incorporation into epoxy coatings effectively prolonged the corrosion pathway.Therefore,QLS-TiO_(2)/WEP demonstrated excellent anti-corrosion performance in high salt,acid,and alkali.Especially under acidic conditions,its|Z|10 mHzwas5.810×10^(7)Ωcm^(2),which improved three orders of magnitude compared with WEP(3.688×10~4Ωcm^(2)).This study innovates the design concept of high-performance biomass functional waterborne epoxy anti-corrosion coating and is conducive to the high-value utilization of biomass.展开更多
The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion res...The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon steel.Scanning electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive spectroscope.The dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite coating.And the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of BTA.The formation of corrosion products was analyzed using X-ray diffraction.In addition,the corrosion resistance mechanism of the coating was also discussed in detail.展开更多
To enhance the wear resistance of graphene oxide(GO)nano-filled epoxy resin(EP)coatings with ex-cellent dispersion,GO were modified using a co-crosslinking strategy between polydopamine(PDA)and polyethyleneimine(PEI)t...To enhance the wear resistance of graphene oxide(GO)nano-filled epoxy resin(EP)coatings with ex-cellent dispersion,GO were modified using a co-crosslinking strategy between polydopamine(PDA)and polyethyleneimine(PEI)through an environmentally friendly,simple and low-cost process.High-density amino-branched PEI and highly adhesive PDA formed covalent bond cross-links with GO(PDA/PEI-GO)through the Michael addition and Schiffbase reactions.With the introduction of amino active sites,the PDA self-polymerization reaction time was significantly shorted from 24 to 6 h.The covalently cross-linked network increased the lamellar spacing of GO and enhanced the interfacial bonds between the PDA/PEI-GO lamellae and EP matrix.Due to the improved dispersion and surface activity of GO,the PDA/PEI-GO nano-filled EP coating exhibited excellent wear resistance.Reciprocating friction with GCr15 stainless steel ball,the average friction coefficient and wear rate of the coating were reduced by 31.9%and 62.7%,respectively,compared to the pure EP coating.In addition,the wear mechanism of the PDA/PEI-GO/EP coating changed from adhesive and fatigue wear to abrasive wear,and it maintained good wear resistance by forming a GO lubrication transfer film on the counterpart surface.Therefore,this study may provide a new strategy for improving the dispersion of graphene in wear-resistant polymer materials for practical applications.展开更多
The zinc-rich epoxy cathodic protection coating is the most widely used anticorrosion material for marine steel.However,traditional conductive fillers lack the intelligent self-healing effect,which limits the long-ter...The zinc-rich epoxy cathodic protection coating is the most widely used anticorrosion material for marine steel.However,traditional conductive fillers lack the intelligent self-healing effect,which limits the long-term anticorrosion performance.Herein,with uniform carbon-coated ZnS(ZnS@C)nanoballs as the smart active release filler,we propose an anticorrosive and self-healing zinc-rich maleic anhydride epoxy coating.Due to the high pore filling efficiency of the nanoballs,the water vapor transmission rate of the coating with an initial corrosion efficiency of 99.92%and a low-frequency impedance of|Z|f=10mHz=3.88×10^(10) Ω·cm^(2),was reduced by 52%.The carbon-shell of the nanoball increases electron transmission paths in the coating and improves conductivity by nearly two orders of magnitude,which effectively activates more Zn-sites and extends the cathodic protection time.Moreover,once the steel-substrate undergoes regional corrosion,the SO_(4)^(2-)hydrolyzes from the ZnS-core of the nanoball and reacts with iron ions on the corroded area accurately and intelligently to fill the gap and self-heals into a new dense barrier layer(Fe_(2)(SO_(4))_(3),etc.),which significantly improves the shielding protection ability during the long-term usage of the coating.The effective anticorrosion time of the proposed coating could be up to 3,400 h.展开更多
Polymer nanocomposite coatings have attracted great interest in the anticorrosion fields due to their excellent properties.Nanofillers are necessary to achieve high anticorrosion performance of the polymer coating.Her...Polymer nanocomposite coatings have attracted great interest in the anticorrosion fields due to their excellent properties.Nanofillers are necessary to achieve high anticorrosion performance of the polymer coating.Herein,we report a wet-chemical template strategy to prepare large-size ZrO_(2)nanosheets,in which the Zr^(4+)ions are anchored on the surface of a graphene oxide template via electrostatic adsorption,followed by a thermal treatment process to remove graphene.Atomic force microscopy(AFM)and scanning electron microscopy(SEM)images show that the size and thickness of as-prepared ZrO_(2)nanosheets are more than 2μm and~4.5 nm,respectively.The micron-scale ultrathin two-dimension(2D)ZrO_(2)nanosheets,for the first time,are utilized as the anticorrosive fillers in the epoxy coating to reduce the porosity,consequently promoting the gas and water barrier properties of the composite coating.The polymer coating containing 1.0 wt%ZrO_(2)nanosheets shows a high initial impedance(89.1 GΩ·cm^(2))that can protect the metal substrate from being corroded during long-term immersion(60 days),which is better than that of the reduced graphene oxide(rGO)-incorporated coating and the ZrO_(2)nanoparticles-incorporated coating.This work offers valuable insights into the design and preparation of novel and efficient 2D electric-inert nanofillers for anticorrosion coatings.展开更多
2-aminoterephthalic acid(DATPA)was used as a binding agent for grafting nano-Fe_(2)O_(3)onto the surface of graphene oxide(GO).Covalent bonding of this composite filler GOF was verified by SEM,XRD and FT-IR.The result...2-aminoterephthalic acid(DATPA)was used as a binding agent for grafting nano-Fe_(2)O_(3)onto the surface of graphene oxide(GO).Covalent bonding of this composite filler GOF was verified by SEM,XRD and FT-IR.The results indicated that the GOF fillers were dispersed well in the epoxy coating matrix.The compatibility between the filler and epoxy coating was enhanced,resulting in a good bonding of the filler and coating matrix.EIS results revealed that the|Z|_(0.01Hz)values of GOF/EP coating kept at 10^(7)Ωcm^(2)after 7 cycles under alternating hydrostatic pressure(AHP)condition,which is higher than that of GO/EP coating(2.38×10^(6)Ωcm^(2)).Well bonded GOF/epoxy resin interface is the reason for resisting the“push-pull”damage of AHP.展开更多
In this manuscript,the neat epoxy(EP)and functionalized Fe_(3)O_(4)(G-Fe_(3)O_(4))reinforced epoxy(G-Fe_(3)O_(4)/EP)coatings were cured under different temperatures,and the effect of the low curing temperature on the ...In this manuscript,the neat epoxy(EP)and functionalized Fe_(3)O_(4)(G-Fe_(3)O_(4))reinforced epoxy(G-Fe_(3)O_(4)/EP)coatings were cured under different temperatures,and the effect of the low curing temperature on the anticorrosion performance was investigated.The experimental results show that the epoxy-amine ring-open addition reaction mainly exists in the curing process,and the activation energies of the reaction for the two coatings are 55.84 and 53.29 kJ/mol,respectively.For the coatings cured at the low temperature,almost no pores could be detected on the fracture surface,but the presentence of the rough regions reflects the poor curing state.As compared with the samples cured at the high temperature,the anticorrosion performance of the coatings with the low curing temperature is worse,and the decrease rate of the anticorrosion performance is slower,because of the poor curing state and low adhesion obtained at the low temperature.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.U1909220 and 52003283)Science and Technology Innovation 2025 Major Project of Ningbo (Nos.2021Z092, 2022Z111 and 2022Z160)+1 种基金Defense Industrial Technology Development Program (No.JCKY2021513B001)the Research Project of Technology Application for Public Welfare of Ningbo City (No.202002N3122)。
文摘It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is still a challenge because of the common complex design and synthesis. Herein, the bio-based monomer protocatechuic acid(PCA) was used as raw material, the catechol structure with high bonding and antibacterial properties was introduced into the flexible alkane segment of ethylene glycol diglycidyl ether(EGDE) through an efficient, and green method, and it was cured with isophorone diamine(IPDA) to prepare corresponding thermosets. The cured resins exhibited excellent allaround qualities, particularly in bonding and antibacterial. When 30% PCA was added to pure epoxy resin, the adhesion between substrate and coating increased from 4.40 MPa to 13.60 MPa and the antibacterial rate of coating against E. coli and S. aureus could approach 100%. All of this is due to the fact that the catechol structure present in PCA has the ability to interact with various substrates and alter the permeability of bacterial cell membranes. The architecture of this method offers a fresh approach to dealing with the issues of challenging raw material selection and complex synthesis techniques.
基金the National Natural Science Foundation of China(Grant number 51771178)Shaanxi Outstanding Youth Fund project(Grant number 2021JC-45)+2 种基金Key international cooperation projects in Shaanxi Province(Grant number 2020KWZ-007)the Major Program of Science and Technology in Shaanxi Province(Grant number20191102006)Open Fund of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body(Grant number 32115019)。
文摘The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient protection.In the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly technique.The outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)film.The FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier capability.The Ce film connects the outer layer with the substrate,showing the transition effect.The corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling behavior.The synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.
基金the National Natural Science Foundation of China(Nos.51705435 and 51575459)the Key Project of Sichuan Department of Science and Technology(Nos.2018JZ0048 and 2019YFG0292)。
文摘Two-dimensional Ti_(3)C_(2)T_(x) flakes have great application potential in various areas due to their optical,electronic,electrochemical and mechanical properties,but their anti-corrosion and wear-resistance performance were not well understood.The difficulties in achieving good dispersity and interface interaction of inorganic additives in organic coatings hinder the incorporation of Ti_(3)C_(2)T_(x) into the epoxy coating.Here,few-layered Ti_(3)C_(2)T_(x) sheets with amino-functionalization were prepared,and as reinforced-additives were added into the waterborne epoxy coating.Anti-corrosion and tribological properties of as-prepared composite coatings were investigated in detail.The results reveal that the composite coating with 0.5 wt.%amino-functionalized Ti_(3)C_(2)T_(x) sheets shows excellent corrosion protection(the lowest frequency impedance was 3.12×10^(9) cm^(2))and wear resistance(wear rate was reduced by 72.74%).The greatly improving performance of composite coatings mainly depends on:(a)good dispersity and compatibility of amino-functionalized Ti_(3)C_(2)T_(x) in organic matrix,(b)high adhesion strength between coating and metal substrate and(c)the intrinsic properties of Ti3C2Tx sheets.The work provides a good path for applications of MXene as multifunctional additives.
基金Supported by the National Department Public Benefit Research Foundation(No.201005028)the National Key Technology Research and Development Program during the Twelfth Five-Year Plan Period of China(No.2012BAB15B01)
文摘The surface of ZrO2 nanoparticles was modified by styrene coupling grafting method to improve the dispersion and interaction of the nanoparticles with the epoxy coating in which the modified ZrO2 nanoparticles were used as an additive. The grafting performance and microstructure of the nano- ZrO2/epoxy coating were analyzed by Fourier transformation infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The corrosion behavior of the nano-ZrO2/epoxy coating on mild steel was evaluated in neutral 3.5 wt% NaC1 solution using electrochemical impedance spectroscopy （EIS）. Both the coating capacitance and coating resistance fitted by the equivalent circuit from EIS were used to evaluate the protective performance of the coating towards the mild steel. The results show a superior stability and efficient corrosion protection by the modified ZrO2 nanoparticles. The epoxy coating containing 2 wt% modified ZrO2 nanoparticles exhibited the best corrosion performance among all the coating specimens. This research may provide an insight into the protection of mild steel using modified epoxy coatings.
文摘Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy（EIS） and immersion test. Open circuit potential（OCP） measurements and immersion tests were also carried out to better understand the behavior of zinc rich coating. EIS and OCP measurements showed that addition of 1 wt% clay improved the cathodic protection duration and sacrificial properties of the epoxy zinc rich coating. Transmission electron microscopy（TEM） photographs confirmed that clay nanoparticles were successfully dispersed in the coating matrix loaded with 1 wt% clay. Immersion test results indicated that addition of 1 wt% clay nanoparticles in zinc rich epoxy coatings increased the cathodic protection ability of coatings.
基金supported financially by the Key Technology of Corrosion Control on Wind Power Equipment Academician Workstation Project(No.2013B090400023)。
文摘The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe operation.In this work,we presented a method to protect the rusted steel by ru st conversion treatment and epoxy coating.Tannic acid was selected as rust conversion agent.Tannic acid,D-limonene and nano-ZrO_(2)were used to improve the corrosion resistance of epoxy coatings.The Raman spectra,Xray diffraction and 3 D confocal images were used to characterize the rust conversion reaction.Ad hesion test showed that the loss of wet adhesion of the optimal coating was relatively low due to the addition of tannic acid,limonene and nano-ZrO(2).The corrosion resistance of five different coatings was investigated by scanning electron microscopy(SEM)and electrochemical analysis.Results show that after 264 h acid immersion,the low frequency resistance of the optimal coating consisting of rust conversion treatment and additives is 10^(7)Ωcm^(2),three orders magnitude higher than that of the pristine coating.Moreover,SEM indicates that the optimal coating possesses a smooth surface and an unbroken interface between substrate and coating.Accordingly,the corrosion-resistant mechanism of the hybrid coating is proposed.
基金Project(51001007) supported by the National Natural Science Foundation of ChinaProject(2011ZE51057) supported by the Aero Science Foundation of China
文摘A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution.
基金supported by the National Natural Science Foundation of China (No.41506098)the China Postdoctoral Science Foundation (No.2015M580528)the Open Fund Project of Key Laboratory of Marine Materials and Related Technologies (No.LMMTKFKT-2014-008) in the Chinese Academy of Sciences
文摘Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings displayed outstanding barrier properties against H20 molecule compared to the neat epoxy coating. Open circuit potential （OCP）, Tafel and electrochemical impedance spectroscopy （EIS） analysis confirmed that the corrosion rate exhibited by composite coatings with 0.5 wt% G was an order of magnitude lower than that of neat epoxy coating. Salt spray test results revealed superior corrosion resistance offered by the composite coating.
基金financially supported by the National Natural Science Foundation of China(Nos.52001214 and 51902204)the China Postdoctoral Science Foundation(No.2020M672796)+2 种基金the Bureau of Industry and Information Technology of Shenzhen(No.201901171518)the Shenzhen Science and Technology Program(No.JSGG20191129141016881)the technical support provided by Instrumental Analysis Center of Shenzhen University(Xili Campus)and the Shiyanjia lab(www.shiyanjia.com)。
文摘A facile and environmentally-friendly method is developed to prepare graphene/waterborne epoxy(WEP)composite coatings.The graphene nanosheets are produced with electrochemical-exfoliation in the solution containing surfactants,cetyl trimethyl ammonium bromide(CTAB)and sodium dodecyl sulfate(SDS).The nanosheets containing solution thus formed are subjected to a quick dialysis and then directly used as a diluent for WEP without any further treatment.This preparation method overcomes the commonly identified problems of aggregations and‘corrosion promotion’effect associated with graphene,and increases the impedance of the composite coatings by more than two orders of magnitude.The analysis of anticorrosion performance suggested that the presence of surfactants not only improves the dispersibility of graphene nanosheets but also endows the composite coatings with both barrier and corrosion inhibition capabilities.The strategy reported herein may pave the path to the large-scale production of graphene anticorrosion coatings.
文摘Based on a two-dimensional(2D)Co-MOF(Co_(2)(OH)_(2)BDC)with a self-contained organic interface and low conductivity,a composite epoxy coating(2D Co_(2)(OH)_(2)BDC-PAN/EP)was constructed by a two-step preparation.First,a polyacrylonitrile(PAN)nanofiber membrane was electrospuned on the surface of Q235 steel,followed by coating using the epoxy coating(EP)containing 2D Co_(2)(OH)_(2)BDC.The 2D Co_(2)(OH)_(2)BDC-PAN/EP composite epoxy coatings showed robust mechanical performance and excellent corrosion resistance capacity.
文摘This paper presents the results regarding the effect of nano aluminum powder pigment concentration on the protective properties of waterborne epoxy films in 3.5 wt pct NaCl solution. The anticorrosive performance of the coatings with 0.5, 1, and 3 wt pct pigments and none pigment were investigated using electrochemical impedance spectroscopy （EIS）, scanning electron microscopy （SEM） and Raman spectroscopy techniques. The results show that adding appropriate amount of nano-aluminium powder pigment can enhance the barrier properties of the epoxy coating, which is attributed to the surface effect of nanoparticles and the compatibility of the pigment with the waterborne epoxy coatings.
文摘Introducing inorganic nanomaterials into a polymer matrix greatly improves the anticorrosion performance of epoxy coatings(EP);however,poor compatibility between the materials can limit the improvement in properties.In this work,based on the high interface compatibility of two-dimensional(2D)Co_(2)(OH)_(2)BDC(BDC=1,4-benzenedicarboxylate)in the epoxy coating that we reported in previous work,we fabricated a 2D Co_(2)(OH)_(2)BDC-halloysite nanotube(HNT)nanocomposite have a structure consisting of alternating of nanosheets and nanotube by in situ synthesis.The nanocomposite was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,and scanning electron microscopy.The mechanical and anticorrosion performance of the 2D Co_(2)(OH)_(2)BDC-HNT/EP coating was evaluated by mechanical tests and electrochemical impedance spectroscopy spectra.Compared with a conventional unreinforced epoxy coating,the 2D Co_(2)(OH)_(2)BDC-HNT/EP coating had higher mechanical strength and toughness,and the low-frequency impedance modulus of 2D Co_(2)(OH)_(2)BDC-HNT/EP coating was increased by three orders of magnitude,demonstrating the high corrosion resistance of our reinforced coating.
基金financially supported by the National Natural Science Foundation of China(No.52075391).
文摘The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals,and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5%NaCl solution.The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion,synergistic protection,and substrate damage.Besides,Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating.This organic monolayer coating,in conjunction with the synergistic inorganic conversion layer comprising Al_(2)O_(3),TiO_(2),2H_(2)O,ZrO_(2),2H_(2)O,effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.
基金financially supported by the National Natural Science Foundation of China(No.22278092)the Young Talent Support Project of Guangzhou Association for Science and Technology(No.QT2024-004)+2 种基金the Science and Technology Research Project of Guangzhou(Nos.2023A03J0034,2023A04J0077,202102020467 and 2023A03J0064)the Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.202255464)the National College Student Innovation Training Program of Guangzhou University(No.202411078020)
文摘Combining conventional waterborne epoxy coatings(WEP)with specific functionalities is essential to increase their service life.However,designing multifunctional protective coatings with tunable interfaces to improve their corrosion and weather resistance remains challenging.In this study,based on intermolecular forces between quaternized lignosulfonate(QLS)and tertbutyl titanate,we prepared QLS-TiO_(2)nanocomposite with structural regularity and strong chemical bonding by a simple one-pot method.It was further used for doped modified WEP to prepare a high-performance QLS-TiO_(2)/WEP coating.The results showed that QLS-TiO_(2)can effectively scavenge radicals,absorb and reflect strong ultraviolet rays,and exhibit high dispersibility and interfacial compatibility in the epoxy matrix.Consequently,QLS-TiO_(2)/WEP coating demonstrated excellent weathering resistance,with the polymer chain segments within the coatings remaining intact after 240 h of accelerated aging test.Furthermore,QLS-TiO_(2)exhibited chemical stability and impressive anti-corrosion properties.Its incorporation into epoxy coatings effectively prolonged the corrosion pathway.Therefore,QLS-TiO_(2)/WEP demonstrated excellent anti-corrosion performance in high salt,acid,and alkali.Especially under acidic conditions,its|Z|10 mHzwas5.810×10^(7)Ωcm^(2),which improved three orders of magnitude compared with WEP(3.688×10~4Ωcm^(2)).This study innovates the design concept of high-performance biomass functional waterborne epoxy anti-corrosion coating and is conducive to the high-value utilization of biomass.
基金financially supported by the National Natural Science Foundation of China(22178242)the Shanxi Provincial Key Research and Development Project(202102040201009).
文摘The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon steel.Scanning electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive spectroscope.The dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite coating.And the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of BTA.The formation of corrosion products was analyzed using X-ray diffraction.In addition,the corrosion resistance mechanism of the coating was also discussed in detail.
基金This work was financially supported by the Shanxi Province Science and Technology Major Project for New Materials Tech-nology(No.20181102014)the Shanxi Province 1331 Project Key Innovation Team of Polymeric Functional New Materials,the Natural Science Foundation of Shanxi Province of China(No.20210302123036)the Program for the Excellent Young Aca-demic Leaders of Higher Learning Institutions of Shanxi Province.
文摘To enhance the wear resistance of graphene oxide(GO)nano-filled epoxy resin(EP)coatings with ex-cellent dispersion,GO were modified using a co-crosslinking strategy between polydopamine(PDA)and polyethyleneimine(PEI)through an environmentally friendly,simple and low-cost process.High-density amino-branched PEI and highly adhesive PDA formed covalent bond cross-links with GO(PDA/PEI-GO)through the Michael addition and Schiffbase reactions.With the introduction of amino active sites,the PDA self-polymerization reaction time was significantly shorted from 24 to 6 h.The covalently cross-linked network increased the lamellar spacing of GO and enhanced the interfacial bonds between the PDA/PEI-GO lamellae and EP matrix.Due to the improved dispersion and surface activity of GO,the PDA/PEI-GO nano-filled EP coating exhibited excellent wear resistance.Reciprocating friction with GCr15 stainless steel ball,the average friction coefficient and wear rate of the coating were reduced by 31.9%and 62.7%,respectively,compared to the pure EP coating.In addition,the wear mechanism of the PDA/PEI-GO/EP coating changed from adhesive and fatigue wear to abrasive wear,and it maintained good wear resistance by forming a GO lubrication transfer film on the counterpart surface.Therefore,this study may provide a new strategy for improving the dispersion of graphene in wear-resistant polymer materials for practical applications.
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(Nos.2022R1A2C1007070,2019R1C1C1006310,2021K2A9A2A06044652,2020R1I1A1A01072996,and 2019R1A2C1002844).
文摘The zinc-rich epoxy cathodic protection coating is the most widely used anticorrosion material for marine steel.However,traditional conductive fillers lack the intelligent self-healing effect,which limits the long-term anticorrosion performance.Herein,with uniform carbon-coated ZnS(ZnS@C)nanoballs as the smart active release filler,we propose an anticorrosive and self-healing zinc-rich maleic anhydride epoxy coating.Due to the high pore filling efficiency of the nanoballs,the water vapor transmission rate of the coating with an initial corrosion efficiency of 99.92%and a low-frequency impedance of|Z|f=10mHz=3.88×10^(10) Ω·cm^(2),was reduced by 52%.The carbon-shell of the nanoball increases electron transmission paths in the coating and improves conductivity by nearly two orders of magnitude,which effectively activates more Zn-sites and extends the cathodic protection time.Moreover,once the steel-substrate undergoes regional corrosion,the SO_(4)^(2-)hydrolyzes from the ZnS-core of the nanoball and reacts with iron ions on the corroded area accurately and intelligently to fill the gap and self-heals into a new dense barrier layer(Fe_(2)(SO_(4))_(3),etc.),which significantly improves the shielding protection ability during the long-term usage of the coating.The effective anticorrosion time of the proposed coating could be up to 3,400 h.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 21476019 and 21676017)
文摘Polymer nanocomposite coatings have attracted great interest in the anticorrosion fields due to their excellent properties.Nanofillers are necessary to achieve high anticorrosion performance of the polymer coating.Herein,we report a wet-chemical template strategy to prepare large-size ZrO_(2)nanosheets,in which the Zr^(4+)ions are anchored on the surface of a graphene oxide template via electrostatic adsorption,followed by a thermal treatment process to remove graphene.Atomic force microscopy(AFM)and scanning electron microscopy(SEM)images show that the size and thickness of as-prepared ZrO_(2)nanosheets are more than 2μm and~4.5 nm,respectively.The micron-scale ultrathin two-dimension(2D)ZrO_(2)nanosheets,for the first time,are utilized as the anticorrosive fillers in the epoxy coating to reduce the porosity,consequently promoting the gas and water barrier properties of the composite coating.The polymer coating containing 1.0 wt%ZrO_(2)nanosheets shows a high initial impedance(89.1 GΩ·cm^(2))that can protect the metal substrate from being corroded during long-term immersion(60 days),which is better than that of the reduced graphene oxide(rGO)-incorporated coating and the ZrO_(2)nanoparticles-incorporated coating.This work offers valuable insights into the design and preparation of novel and efficient 2D electric-inert nanofillers for anticorrosion coatings.
基金financially supported by the National Natural Science Foundation of China(Nos.U20A20233 and 51901040)the Fundamental Research Funds for the Central Universities(No.N2102014)
文摘2-aminoterephthalic acid(DATPA)was used as a binding agent for grafting nano-Fe_(2)O_(3)onto the surface of graphene oxide(GO).Covalent bonding of this composite filler GOF was verified by SEM,XRD and FT-IR.The results indicated that the GOF fillers were dispersed well in the epoxy coating matrix.The compatibility between the filler and epoxy coating was enhanced,resulting in a good bonding of the filler and coating matrix.EIS results revealed that the|Z|_(0.01Hz)values of GOF/EP coating kept at 10^(7)Ωcm^(2)after 7 cycles under alternating hydrostatic pressure(AHP)condition,which is higher than that of GO/EP coating(2.38×10^(6)Ωcm^(2)).Well bonded GOF/epoxy resin interface is the reason for resisting the“push-pull”damage of AHP.
基金Project(U2106216)supported by the National Natural Science Foundation of China。
文摘In this manuscript,the neat epoxy(EP)and functionalized Fe_(3)O_(4)(G-Fe_(3)O_(4))reinforced epoxy(G-Fe_(3)O_(4)/EP)coatings were cured under different temperatures,and the effect of the low curing temperature on the anticorrosion performance was investigated.The experimental results show that the epoxy-amine ring-open addition reaction mainly exists in the curing process,and the activation energies of the reaction for the two coatings are 55.84 and 53.29 kJ/mol,respectively.For the coatings cured at the low temperature,almost no pores could be detected on the fracture surface,but the presentence of the rough regions reflects the poor curing state.As compared with the samples cured at the high temperature,the anticorrosion performance of the coatings with the low curing temperature is worse,and the decrease rate of the anticorrosion performance is slower,because of the poor curing state and low adhesion obtained at the low temperature.
