Nafion/polypyrrole and Nafion/Dimethysulfoxid (DMSO) organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic c...Nafion/polypyrrole and Nafion/Dimethysulfoxid (DMSO) organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.展开更多
The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid (DMSO) organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and...The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid (DMSO) organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.展开更多
The degradation coefficient is proposed to evaluate the degradation degree of organic coatings by directly anaIyzing the Bode plots of the electrochemical impedance spectroscopy (EIS) data. This paper investigated t...The degradation coefficient is proposed to evaluate the degradation degree of organic coatings by directly anaIyzing the Bode plots of the electrochemical impedance spectroscopy (EIS) data. This paper investigated the degradation of phenolic epoxy coating/tinplate system by EIS and the degradation coefficient value, which correlates well with the results of breakpoint frequency and variation of phase angle at 10 Hz. Furthermore, the degradation process was confirmed by scanning electron microscope (SEM) and scanning probe microscopy (SPM). It is concluded that degradation coefficient can be used for the fast evaluation of degradation degree of organic coatings in practical appli- cations.展开更多
The development of methods to produce nanoparticles with unique properties via the aerosol route is progressing rapidly. Typical characterization techniques extract particles from the synthesis process for subsequent ...The development of methods to produce nanoparticles with unique properties via the aerosol route is progressing rapidly. Typical characterization techniques extract particles from the synthesis process for subsequent offiine analysis, which may alter the particle characteristics. In this work, we use laser-vaporization aerosol mass spectrometry (LV-AMS) with 70-eV electron ionization for real-time, in-situ nanoparticle characterization. The particle characteristics are examined for various aerosol synthesis methods, degrees of sintering, and for controlled condensation of organic material to simulate surface coating/functionalization. The LV-AMS is used to characterize several types of metal nanoparticles (Ag, Au, Pd, PdAg, Fe, Ni, and Cu). The degree of oxidation of the Fe and Ni nanoparticles is found to increase with increased sintering temperature, while the surface organic-impurity content of the metal particles decreases with increased sintering temperature. For aggregate metal particles, the organic-impurity content is found to be similar to that of a monolayer. By comparing different equivalent-diameter measurements, we demonstrate that the LV-AMS can be used in tandem with a differential mobility analyzer to determine the compactness of synthesized metal particles, both during sintering and during material addition for surface functionalization. Further, materials supplied to the particle production line downstream of the particle generators are found to reach the generators as contaminants. The capacity for such in-situ observations is important, as it facilitates rapid response to undesired behavior within the particle production process. This study demonstrates the utility of real-time, in-situ aerosol mass spectrometric measurements to characterize metal nanoparticles obtained directly from the synthesis process line, including their chemical composition, shape, and contamination, providing the potential for effective optimization of process operating parameters.展开更多
Organic polymer coatings have been commonly used in biomedical field,which play an important role in achieving biological antifouling,drug delivery,and bacteriostasis.With the continuous development of polymer science...Organic polymer coatings have been commonly used in biomedical field,which play an important role in achieving biological antifouling,drug delivery,and bacteriostasis.With the continuous development of polymer science,organic polymer coatings can be designed with complex and advanced functions,which is conducive to the construction of biomedical materials with different performances.According to different physical and chemical properties of materials,biomedical organic polymer coating materials are classified into zwitterionic polymers,non-ionic polymers,and biomacromolecules.The strategies of combining coatings with substrates include physical adsorption,chemical grafting,and self-adhesion.Though the coating materials and construction methods are different,many biomedical polymer coatings have been developed to achieve excellent performances,i.e.,enhanced lubrication,anti-inflammation,antifouling,antibacterial,drug release,anti-encrustation,anti-thrombosis,etc.Consequently,a large number of biomedical polymer coatings have been used in artificial lungs,ureteral stent,vascular flow diverter,and artificial joints.In this review,we summarize different types,properties,construction methods,biological functions,and clinical applications of biomedical organic polymer coatings,and prospect future direction for development of organic polymer coatings in biomedical field.It is anticipated that this review can be useful for the design and synthesis of functional organic polymer coatings with various biomedical purposes.展开更多
A new method for pre;baring highly pure and viscous organic smectite has been investigated and developed; The key feature of the method Is the use of a chemical aid with multi-functions of high purification, modificat...A new method for pre;baring highly pure and viscous organic smectite has been investigated and developed; The key feature of the method Is the use of a chemical aid with multi-functions of high purification, modification and chelation, This ensures the preparation of the high performance organic smectite product even using the most conventional organic coating agent.展开更多
A polarizing microscope,X-ray diffraction(XRD),fourier transform infrared spectrometer(FTIR),scanning electron microscope and energy dispersive spectrometer(SEM-EDS),X-ray photoelectron spectroscopy(XPS),and micro com...A polarizing microscope,X-ray diffraction(XRD),fourier transform infrared spectrometer(FTIR),scanning electron microscope and energy dispersive spectrometer(SEM-EDS),X-ray photoelectron spectroscopy(XPS),and micro computed tomography(Micro CT)were used to investigate the relation between the structure and properties of the composite.Meanwhile,the physical properties,mechanical properties and strength mechanism were researched.The experimental results show that the structure and morphology of coated phosphogypsum remain intact in the composite,which shows good compatibility and forms a clear interface layer of transition zone between the coated phosphogypsum and the matrix,conforming to the structure of particle reinforced inorganic composites.The emulsion coated phosphogypsum has a certain strengthening effect on the aluminous rock mineral polymer composite.The compressive strength of the composite can reach 16.5 MPa when the amount of coated phosphogypsum is 40%,and the apparent density is 1.75 g·cm^(-3),which is significantly lower than that of common concrete;the thermal stability of the composite is also improved to a certain extent.Some certain chemical reactions occur in the process of forming the matrix of aluminous rock mineral polymer materials,with a structure of three-dimensional network.The research will provide a new way for the comprehensive utilization of phosphogypsum and low-grade aluminous rock.展开更多
In recent years,the concern about environmental protection is increasing on a world scale.Major manufacturers of home appliances and OA equipment have introduced so-called 'green procurement schemes' for reduc...In recent years,the concern about environmental protection is increasing on a world scale.Major manufacturers of home appliances and OA equipment have introduced so-called 'green procurement schemes' for reducing environmentally harmful substances in manufacturing process and end products. Under such background,a new type of chromate-free organic composite coated electro-galvanized steel sheet with high conductivity was developed by Baosteel,which meets the EU RoHS Directive(Restriction of the Hazardous Substances) and other related laws and regulations on environmental safety.It also provides excellent surface electrical conductivity,corrosion resistance,fingerprint resistance,solvent resistance,coating adhesion, heat resistance,formability and other special properties to meet the demand of manufacture's process of OA machine. Compared with previously developed anti-fingerprinting coated electro-galvanized steel sheet,this newly developed product has a good balance between high corrosion resistance(time to 5%white rust in salt spray test is 120 h for flat panel and 72 h for worked potion) and conductivity(surface electro-resistivity in accordance with LOREAST is less than 0.1 milliohm ) due to the special design of coating's structure.Besides,It also provides the properties of grounding and shielding against electromagnetic waves.The evaluation of surface performances of new product showed that it is comparable or even better than the similar products. Currently,the newly developed product has been commercialized. In this paper,the major properties are discussed,such as corrosion resistance,surface electrical conductivity, fingerprint resistance,solvent resistance,coating adhesion(ink/melamine alkyd paint),heat resistance and formability.Furthermore,the application is also briefly described.展开更多
The heat dissipated pad is made of composite mixing silicon or epoxy resin with thermal conductive inorganic fillers. The heat-dissipation material improves performance as the amount of thermal conductivity filler inc...The heat dissipated pad is made of composite mixing silicon or epoxy resin with thermal conductive inorganic fillers. The heat-dissipation material improves performance as the amount of thermal conductivity filler increases. However, the optimum recipe should be determined by considering the price and pad formability. In this study, high performance thermal pad is made of silicon resin mixed with Al2O3 as a thermally conductive filler. Since Al2O3 is low cost, it can use much filler. Al2O3 has improved slip-ability with organic coating on it to increase the viscosity of the slurry. The same process and the same recipe, could maximize the amount of the filler. As a result, the thermal conductivity is lower by 10%. But the viscosity is reduced by 60%, too. So form-ability is getting priority.展开更多
ZnMOF-BTA,a new metal–organic framework with excellent anti-corrosion properties was prepared and characterized.Polarization and immersion tests in 3.5 wt%NaCl were performed on AA2024-T3 alloy to assess the corrosio...ZnMOF-BTA,a new metal–organic framework with excellent anti-corrosion properties was prepared and characterized.Polarization and immersion tests in 3.5 wt%NaCl were performed on AA2024-T3 alloy to assess the corrosion inhibition ability of ZnMOF-BTA.It showed an inhibition efficiency of more than 90%,indicating excellent corrosion inhibition of ZnMOF-BTA on AA 2024-T3 in NaCl.Moreover,ZnMOF-BTA particles were incorporated into polyurethane coatings to create corrosion-resistant coatings.Electrochemical tests and neutral salt spray analysis were used to assess the corrosion protection ability of ZnMOF-BTA-laden polyurethane coatings.The results of electrochemical impedance spectra clearly showed the outstanding corrosion resistance and durability of ZnMOF-BTA coatings after 1440 h of immersion with a high pore resistance(Rpo)of 1.76×10^(10)Ωcm^(2).In addition,during the cross-cut adhesion test,the coating did not detach from the substrate,and after the impact test,there was scarcely any indication of a fracture,which further supports the notion that the coating has strong adhesion to the substrate.展开更多
Organic anticorrosive aviation coatings are an effective guarantee for aviation structure,since aircraft corrosion can lead to great economic losses.Whether it is during ground parking or air cruises,organic aviation ...Organic anticorrosive aviation coatings are an effective guarantee for aviation structure,since aircraft corrosion can lead to great economic losses.Whether it is during ground parking or air cruises,organic aviation coatings are important barriers to the corrosion of aviation structure.With the vigorous development of the aviation industry,organic aviation coatings continue to meet the challenges of diverse,complex,and harsh service environments.This review analyzes and summarizes the research status of the types and development of organic aviation coatings,influencing factors and mechanisms,experimental methods,calendar life research methods,and modification methods.It also summarizes the research results that have been achieved to date.The current research deficiencies in the equivalence relationship between atmospheric exposure and artificial acceleration,failure criteria and life prediction were pointed out,and nano-modification technology,and future research strategies and directions that need breakthroughs are discussed.展开更多
The current distributions over carbon steel under iron red alkyd primer exposed to 3.5% sodium chloride solution were mapped using the wire beam electrode (WBE). The electrochemical impedance spectroscopy (EIS) of...The current distributions over carbon steel under iron red alkyd primer exposed to 3.5% sodium chloride solution were mapped using the wire beam electrode (WBE). The electrochemical impedance spectroscopy (EIS) of the WBE was carded out to analyze the performance of coating delamination and corrosion behavior of carbon steel beneath defective coating. The EIS data revealed that protective capability of coating decreased with immersion time and the degree of cathodic delamination showed a rapid rise. The current density distribution of WBE indicated that cathodic sites was located at the defect at the beginning of immersion and gradually spread into the intact coating. The cathodic regions were distinguished from the anodic area and distributed over the WBE. The changes of cathodic sites could reflect the deterioration process of defective coating. The cathodic area ratio was a more useful parameter than the cathodic delamination degree to evaluate the coating cathodic delamination. The polarity reversals of electrodes at the defect and beneath coating were observed. A simple discussion of relationship between the blister and the polarity reversal was made from a standpoint of electrochemical distribution. WBE method was able to map and record the changes of local cathodic sites beneath defective coating in real time, which could provide more detailed information about the local degradation of coating.展开更多
The degradation process of organosol coated tinplate in beverage was investigated by electrochemical noise (EN) technique combined with morphology characterization.EN data were analyzed using phase space reconstructio...The degradation process of organosol coated tinplate in beverage was investigated by electrochemical noise (EN) technique combined with morphology characterization.EN data were analyzed using phase space reconstruction theory.With the correlation dimensions obtained from the phase space reconstruction,the chaotic behavior of EN was quantitatively evaluated.The results show that both electrochemical potential noise (EPN) and electrochemical current noise (ECN) have chaotic properties.The correlation dimensions of EPN increase with corrosion extent,while those of ECN seem nearly unchanged.The increased correlation dimensions of EPN during the degradation process are associated with the increased susceptibility to local corrosion.展开更多
Low alloy steels are widely used in bridges,construction,chemical and various equipment and metal components due to their low cost and excellent mechanical strength.Information in the literature related to the prepara...Low alloy steels are widely used in bridges,construction,chemical and various equipment and metal components due to their low cost and excellent mechanical strength.Information in the literature related to the preparation,advantages and disadvantages,and applications along with research progress of various types of protective coatings suitable for low-alloy steel surfaces is reviewed,while a conclusive and comparative analysis is also afforded to the numerous factors influencing the protective ability of coatings.The characteristics of coatings drawn from the latest published literature are discussed and suggest that the modification of traditional metal coatings and the development of new organic coatings under the consideration of environmental protection,low cost,simplicity and large-scale industrial application are simultaneously proceeding,which holds promise for improving the understanding of corrosion protection in related fields and helps to address some of the limitations identified with more conventional coating techniques.展开更多
In order to investigate the anticorrosion performance of the organic coating/metal system, electrochemical impedance spectra (EIS) were measured in the 3.5wt% NaCl solution, the chemical component and the formation ...In order to investigate the anticorrosion performance of the organic coating/metal system, electrochemical impedance spectra (EIS) were measured in the 3.5wt% NaCl solution, the chemical component and the formation of corrosion products scale were analyzed by laser Raman microspectroscopy, and the pattern of the organic coating/metal system was observed by scanning electron microscopy (SEM). The characteristics and the delamination process of the organic coating/metal system were investigated systematically, and the emphases were on the transportation of the corrosive medium and the changes of the coating/metal interface. The results show that the impedance decreases at the initial immersion, then increases at the middle-immersion, and again decreases at last, which is related to the corrosion products scale. The concentration of Cl in the coating, which destroys the corrosion products scale, increases with the immersion time.展开更多
The stresses around bubbles formed on a coating/substrate interface under hydrostatic pressure(HP)and alternating hydrostatic pressure(AHP)were calculated using the finite element method.The results reveal that HP pro...The stresses around bubbles formed on a coating/substrate interface under hydrostatic pressure(HP)and alternating hydrostatic pressure(AHP)were calculated using the finite element method.The results reveal that HP promotes coating failure but does not mechanically destroy the interface,whereas AHP can provide tensile stress on bubbles formed at the interface and accelerate disbonding of the coating.Because of water resistance,a lag time exists for the coating that serves in an AHP environment.The coating can have a better protective performance if the lag time suits the AHP to minimize the impact of the AHP on the interface.展开更多
A two-stage process was used to produce nano-composite epoxy coatings. The first step involved preparing nano-AI concentrates with high concentration and low viscosity, and the second step produced nano- composite epo...A two-stage process was used to produce nano-composite epoxy coatings. The first step involved preparing nano-AI concentrates with high concentration and low viscosity, and the second step produced nano- composite epoxy coatings by mixing the nano-AI concentrates and epoxy resin. Later, the coating was examined with immersion and salt spray tests. The coatings were characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the 5% nano-AI significantly improves the corrosion resistance of the coatings. There are two effects of nano-AI on the coating. Nano-AI is corroded initially to protect the substrate from corrosion, and then the aluminum oxide and aluminum hydroxide were produced after corrosion of nano-AI, which hindered the transmission of corrosion fluid into the coatings.展开更多
To realize a rapid evaluation of coating degradation under alternating hydrostatic pressure(AHP),appropriate physical models of electrochemical impedance spectroscopy(EIS)data fitting were respectively developed for e...To realize a rapid evaluation of coating degradation under alternating hydrostatic pressure(AHP),appropriate physical models of electrochemical impedance spectroscopy(EIS)data fitting were respectively developed for epoxy coatings with and without pigments,based on their different water absorption behaviours.Power-law model was selected to evaluate the anti-permeability of epoxy varnish(EV)coating,which tends to form through pores in the coating structure.On the other hand,two-layer model based on Young theory was developed to evaluate the anti-permeability of pigmented epoxy coating.Consequently,the resistivity profile with coating thickness was calculated as a critical parameter to describe the anti-permeability of coating at different immersion time.The interpretation of water diffusion dynamics based on different coating structures was also given,which is responsible for the choice of distribution models.展开更多
Anticorrosion epoxy coatings from Al and Zn based pigments were synthesized by adjusting their volume ratios, aiming at their increasing anticorrosion performances. The anticorrosion properties were examined via elec-...Anticorrosion epoxy coatings from Al and Zn based pigments were synthesized by adjusting their volume ratios, aiming at their increasing anticorrosion performances. The anticorrosion properties were examined via elec- trochemical impedance spectroscopy, Tafel polarization curve analysis and salt spray test. The coating morphologies before and after the salt spray tests were studied via scanning electron microscopy(SEM). The elemental and chemical compositions of the corroded surfaces of the coatings were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results indicate that the coating composed of Al/Zn at 10:1(volume ratio) displays the maximum anticorrosion performances, which are superior to those of pristine Al or Zn based pigment.展开更多
Implantable electronic devices(IEDs)are widely used by human beings to achieve medical treatment and diagnosis nowadays.However,ideal encapsulation of IEDs is still far from perfect as full prevention of body fluid di...Implantable electronic devices(IEDs)are widely used by human beings to achieve medical treatment and diagnosis nowadays.However,ideal encapsulation of IEDs is still far from perfect as full prevention of body fluid diffusion into the coating remains unsolved.Herein,we develop a high-performance composite coating for IED encapsulation by introducing SiO_(2) nanoparticles into silicone rubber,which synergistically enhances mechanical properties and improves barrier performance.By fabricating composite coatings with different nanosilica contents,3%nanosilica is proved to be an optimal additive content with an excellent combination of improved fracture strength(from 2.5 MPa to 4.5 MPa),increased coating resistance(from 10^(4) to 10^(9) cm^(2))and ideal coating uniformity.Mechanical and electrochemical characterizations subsequently confirm substantially enhanced mechanical properties and barrier performance of the composite coating,which effectively resist crack propagation and impede penetrations of water and chloride ions through the coating.Theoretical calculations further uncover that modified SiO_(2) particles with enriched methyl groups endow a strong bridging effect to interact with silicone rubber monomer,which,together with anti-agglomeration property of methyl groups,contributes to a pronounced improvement in mechanical performance of nanosilica-filled silicone rubber.Benefitting from the enhanced mechanical and barrier properties,the as-fabricated nanosilica-filled silicone rubber demonstrates superior protection for the encapsulated circuits with a significantly improved lifetime(709.1 h)compared to that of circuits coated by pure silicone rubber(472.8 h)and bare circuit boards(1 h),which offers great values for packaging material design in future IED encapsulation.展开更多
文摘Nafion/polypyrrole and Nafion/Dimethysulfoxid (DMSO) organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.
文摘The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid (DMSO) organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.
基金Supported by Major State Basic Research Program of China ("973"Program,No. 2011CB610500)
文摘The degradation coefficient is proposed to evaluate the degradation degree of organic coatings by directly anaIyzing the Bode plots of the electrochemical impedance spectroscopy (EIS) data. This paper investigated the degradation of phenolic epoxy coating/tinplate system by EIS and the degradation coefficient value, which correlates well with the results of breakpoint frequency and variation of phase angle at 10 Hz. Furthermore, the degradation process was confirmed by scanning electron microscope (SEM) and scanning probe microscopy (SPM). It is concluded that degradation coefficient can be used for the fast evaluation of degradation degree of organic coatings in practical appli- cations.
文摘The development of methods to produce nanoparticles with unique properties via the aerosol route is progressing rapidly. Typical characterization techniques extract particles from the synthesis process for subsequent offiine analysis, which may alter the particle characteristics. In this work, we use laser-vaporization aerosol mass spectrometry (LV-AMS) with 70-eV electron ionization for real-time, in-situ nanoparticle characterization. The particle characteristics are examined for various aerosol synthesis methods, degrees of sintering, and for controlled condensation of organic material to simulate surface coating/functionalization. The LV-AMS is used to characterize several types of metal nanoparticles (Ag, Au, Pd, PdAg, Fe, Ni, and Cu). The degree of oxidation of the Fe and Ni nanoparticles is found to increase with increased sintering temperature, while the surface organic-impurity content of the metal particles decreases with increased sintering temperature. For aggregate metal particles, the organic-impurity content is found to be similar to that of a monolayer. By comparing different equivalent-diameter measurements, we demonstrate that the LV-AMS can be used in tandem with a differential mobility analyzer to determine the compactness of synthesized metal particles, both during sintering and during material addition for surface functionalization. Further, materials supplied to the particle production line downstream of the particle generators are found to reach the generators as contaminants. The capacity for such in-situ observations is important, as it facilitates rapid response to undesired behavior within the particle production process. This study demonstrates the utility of real-time, in-situ aerosol mass spectrometric measurements to characterize metal nanoparticles obtained directly from the synthesis process line, including their chemical composition, shape, and contamination, providing the potential for effective optimization of process operating parameters.
基金supported by the National Natural Science Foundation of China(Nos.52275199 and 52335004)Beijing–Tianjin–Hebei Fundamental Research Cooperation Project(No.J230001).
文摘Organic polymer coatings have been commonly used in biomedical field,which play an important role in achieving biological antifouling,drug delivery,and bacteriostasis.With the continuous development of polymer science,organic polymer coatings can be designed with complex and advanced functions,which is conducive to the construction of biomedical materials with different performances.According to different physical and chemical properties of materials,biomedical organic polymer coating materials are classified into zwitterionic polymers,non-ionic polymers,and biomacromolecules.The strategies of combining coatings with substrates include physical adsorption,chemical grafting,and self-adhesion.Though the coating materials and construction methods are different,many biomedical polymer coatings have been developed to achieve excellent performances,i.e.,enhanced lubrication,anti-inflammation,antifouling,antibacterial,drug release,anti-encrustation,anti-thrombosis,etc.Consequently,a large number of biomedical polymer coatings have been used in artificial lungs,ureteral stent,vascular flow diverter,and artificial joints.In this review,we summarize different types,properties,construction methods,biological functions,and clinical applications of biomedical organic polymer coatings,and prospect future direction for development of organic polymer coatings in biomedical field.It is anticipated that this review can be useful for the design and synthesis of functional organic polymer coatings with various biomedical purposes.
文摘A new method for pre;baring highly pure and viscous organic smectite has been investigated and developed; The key feature of the method Is the use of a chemical aid with multi-functions of high purification, modification and chelation, This ensures the preparation of the high performance organic smectite product even using the most conventional organic coating agent.
基金Funded by the Science and Technology Support Plan of Guizhou Province(No.[2021]482)the Provincial University Joint Fund Project of Guizhou Science and Technology agency(No.[2014]7656)+1 种基金the Science and Technology Plan Project of Guizhou Province(No.[2020]1Z045)the Chunhui Plan of the National Department of Education of China(No.Z2006-1-52003)。
文摘A polarizing microscope,X-ray diffraction(XRD),fourier transform infrared spectrometer(FTIR),scanning electron microscope and energy dispersive spectrometer(SEM-EDS),X-ray photoelectron spectroscopy(XPS),and micro computed tomography(Micro CT)were used to investigate the relation between the structure and properties of the composite.Meanwhile,the physical properties,mechanical properties and strength mechanism were researched.The experimental results show that the structure and morphology of coated phosphogypsum remain intact in the composite,which shows good compatibility and forms a clear interface layer of transition zone between the coated phosphogypsum and the matrix,conforming to the structure of particle reinforced inorganic composites.The emulsion coated phosphogypsum has a certain strengthening effect on the aluminous rock mineral polymer composite.The compressive strength of the composite can reach 16.5 MPa when the amount of coated phosphogypsum is 40%,and the apparent density is 1.75 g·cm^(-3),which is significantly lower than that of common concrete;the thermal stability of the composite is also improved to a certain extent.Some certain chemical reactions occur in the process of forming the matrix of aluminous rock mineral polymer materials,with a structure of three-dimensional network.The research will provide a new way for the comprehensive utilization of phosphogypsum and low-grade aluminous rock.
文摘In recent years,the concern about environmental protection is increasing on a world scale.Major manufacturers of home appliances and OA equipment have introduced so-called 'green procurement schemes' for reducing environmentally harmful substances in manufacturing process and end products. Under such background,a new type of chromate-free organic composite coated electro-galvanized steel sheet with high conductivity was developed by Baosteel,which meets the EU RoHS Directive(Restriction of the Hazardous Substances) and other related laws and regulations on environmental safety.It also provides excellent surface electrical conductivity,corrosion resistance,fingerprint resistance,solvent resistance,coating adhesion, heat resistance,formability and other special properties to meet the demand of manufacture's process of OA machine. Compared with previously developed anti-fingerprinting coated electro-galvanized steel sheet,this newly developed product has a good balance between high corrosion resistance(time to 5%white rust in salt spray test is 120 h for flat panel and 72 h for worked potion) and conductivity(surface electro-resistivity in accordance with LOREAST is less than 0.1 milliohm ) due to the special design of coating's structure.Besides,It also provides the properties of grounding and shielding against electromagnetic waves.The evaluation of surface performances of new product showed that it is comparable or even better than the similar products. Currently,the newly developed product has been commercialized. In this paper,the major properties are discussed,such as corrosion resistance,surface electrical conductivity, fingerprint resistance,solvent resistance,coating adhesion(ink/melamine alkyd paint),heat resistance and formability.Furthermore,the application is also briefly described.
文摘The heat dissipated pad is made of composite mixing silicon or epoxy resin with thermal conductive inorganic fillers. The heat-dissipation material improves performance as the amount of thermal conductivity filler increases. However, the optimum recipe should be determined by considering the price and pad formability. In this study, high performance thermal pad is made of silicon resin mixed with Al2O3 as a thermally conductive filler. Since Al2O3 is low cost, it can use much filler. Al2O3 has improved slip-ability with organic coating on it to increase the viscosity of the slurry. The same process and the same recipe, could maximize the amount of the filler. As a result, the thermal conductivity is lower by 10%. But the viscosity is reduced by 60%, too. So form-ability is getting priority.
基金the National Natural Science Foundation of China(Nos.52171089 and 51571202)the LingChuang Research Project of China National Nuclear Corporation(No.E041F212Z1).
文摘ZnMOF-BTA,a new metal–organic framework with excellent anti-corrosion properties was prepared and characterized.Polarization and immersion tests in 3.5 wt%NaCl were performed on AA2024-T3 alloy to assess the corrosion inhibition ability of ZnMOF-BTA.It showed an inhibition efficiency of more than 90%,indicating excellent corrosion inhibition of ZnMOF-BTA on AA 2024-T3 in NaCl.Moreover,ZnMOF-BTA particles were incorporated into polyurethane coatings to create corrosion-resistant coatings.Electrochemical tests and neutral salt spray analysis were used to assess the corrosion protection ability of ZnMOF-BTA-laden polyurethane coatings.The results of electrochemical impedance spectra clearly showed the outstanding corrosion resistance and durability of ZnMOF-BTA coatings after 1440 h of immersion with a high pore resistance(Rpo)of 1.76×10^(10)Ωcm^(2).In addition,during the cross-cut adhesion test,the coating did not detach from the substrate,and after the impact test,there was scarcely any indication of a fracture,which further supports the notion that the coating has strong adhesion to the substrate.
基金co-supported by the National Science and Technology Major Special Funding,China(No.J2019-I-0016-0015)the National Natural Science Foundation of China(No.52175155)the Supported Fund for Excellent Doctoral Dissertation of Air Force Engineering University,China(No.KGD082520001).
文摘Organic anticorrosive aviation coatings are an effective guarantee for aviation structure,since aircraft corrosion can lead to great economic losses.Whether it is during ground parking or air cruises,organic aviation coatings are important barriers to the corrosion of aviation structure.With the vigorous development of the aviation industry,organic aviation coatings continue to meet the challenges of diverse,complex,and harsh service environments.This review analyzes and summarizes the research status of the types and development of organic aviation coatings,influencing factors and mechanisms,experimental methods,calendar life research methods,and modification methods.It also summarizes the research results that have been achieved to date.The current research deficiencies in the equivalence relationship between atmospheric exposure and artificial acceleration,failure criteria and life prediction were pointed out,and nano-modification technology,and future research strategies and directions that need breakthroughs are discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 51131005)
文摘The current distributions over carbon steel under iron red alkyd primer exposed to 3.5% sodium chloride solution were mapped using the wire beam electrode (WBE). The electrochemical impedance spectroscopy (EIS) of the WBE was carded out to analyze the performance of coating delamination and corrosion behavior of carbon steel beneath defective coating. The EIS data revealed that protective capability of coating decreased with immersion time and the degree of cathodic delamination showed a rapid rise. The current density distribution of WBE indicated that cathodic sites was located at the defect at the beginning of immersion and gradually spread into the intact coating. The cathodic regions were distinguished from the anodic area and distributed over the WBE. The changes of cathodic sites could reflect the deterioration process of defective coating. The cathodic area ratio was a more useful parameter than the cathodic delamination degree to evaluate the coating cathodic delamination. The polarity reversals of electrodes at the defect and beneath coating were observed. A simple discussion of relationship between the blister and the polarity reversal was made from a standpoint of electrochemical distribution. WBE method was able to map and record the changes of local cathodic sites beneath defective coating in real time, which could provide more detailed information about the local degradation of coating.
基金Supported by Major State Basic Research Program of China ("973" Program,No. 2011CB610505)Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120032110029)
文摘The degradation process of organosol coated tinplate in beverage was investigated by electrochemical noise (EN) technique combined with morphology characterization.EN data were analyzed using phase space reconstruction theory.With the correlation dimensions obtained from the phase space reconstruction,the chaotic behavior of EN was quantitatively evaluated.The results show that both electrochemical potential noise (EPN) and electrochemical current noise (ECN) have chaotic properties.The correlation dimensions of EPN increase with corrosion extent,while those of ECN seem nearly unchanged.The increased correlation dimensions of EPN during the degradation process are associated with the increased susceptibility to local corrosion.
基金This paper is supported by Key Scientific Research Project in Shanxi Province(Grant Nos.201903D111008 and 202003D111001)National Natural Science Foundation of China(Grant No.52071227)+4 种基金Fundamental Research Program of Shanxi Province(Grant No.202103021223293)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2021L306)Scientific Research Fund of Taiyuan University of Science and Technology(Grant No.20202044)Award Fund for Outstanding Doctors in Shanxi Province(Grant No.20212041)Postgraduate Education Innovation Project of Shanxi Province(Grant Nos.2022Y686 and 2022Y684).
文摘Low alloy steels are widely used in bridges,construction,chemical and various equipment and metal components due to their low cost and excellent mechanical strength.Information in the literature related to the preparation,advantages and disadvantages,and applications along with research progress of various types of protective coatings suitable for low-alloy steel surfaces is reviewed,while a conclusive and comparative analysis is also afforded to the numerous factors influencing the protective ability of coatings.The characteristics of coatings drawn from the latest published literature are discussed and suggest that the modification of traditional metal coatings and the development of new organic coatings under the consideration of environmental protection,low cost,simplicity and large-scale industrial application are simultaneously proceeding,which holds promise for improving the understanding of corrosion protection in related fields and helps to address some of the limitations identified with more conventional coating techniques.
文摘In order to investigate the anticorrosion performance of the organic coating/metal system, electrochemical impedance spectra (EIS) were measured in the 3.5wt% NaCl solution, the chemical component and the formation of corrosion products scale were analyzed by laser Raman microspectroscopy, and the pattern of the organic coating/metal system was observed by scanning electron microscopy (SEM). The characteristics and the delamination process of the organic coating/metal system were investigated systematically, and the emphases were on the transportation of the corrosive medium and the changes of the coating/metal interface. The results show that the impedance decreases at the initial immersion, then increases at the middle-immersion, and again decreases at last, which is related to the corrosion products scale. The concentration of Cl in the coating, which destroys the corrosion products scale, increases with the immersion time.
基金financially supported by the National Natural Science Foundation of China(Nos.51871049 and 51622106)the National Key R&D Program of China(No.2017YFB0702303)Aclass pilot of the Chinese Academy of Sciences(No.XDA22010303)。
文摘The stresses around bubbles formed on a coating/substrate interface under hydrostatic pressure(HP)and alternating hydrostatic pressure(AHP)were calculated using the finite element method.The results reveal that HP promotes coating failure but does not mechanically destroy the interface,whereas AHP can provide tensile stress on bubbles formed at the interface and accelerate disbonding of the coating.Because of water resistance,a lag time exists for the coating that serves in an AHP environment.The coating can have a better protective performance if the lag time suits the AHP to minimize the impact of the AHP on the interface.
基金the National Key Technology R&D Program (Grant No.2012BAB15B00) for supporting these studies
文摘A two-stage process was used to produce nano-composite epoxy coatings. The first step involved preparing nano-AI concentrates with high concentration and low viscosity, and the second step produced nano- composite epoxy coatings by mixing the nano-AI concentrates and epoxy resin. Later, the coating was examined with immersion and salt spray tests. The coatings were characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the 5% nano-AI significantly improves the corrosion resistance of the coatings. There are two effects of nano-AI on the coating. Nano-AI is corroded initially to protect the substrate from corrosion, and then the aluminum oxide and aluminum hydroxide were produced after corrosion of nano-AI, which hindered the transmission of corrosion fluid into the coatings.
基金financially supported by the National Natural Science Foundation of China(No.51622106 and 51901040)the Fundamental Research Funds for the Central Universities(No.N170203005 and N170212021)the China Postdoctoral Science Foundation(No.2018M640256)。
文摘To realize a rapid evaluation of coating degradation under alternating hydrostatic pressure(AHP),appropriate physical models of electrochemical impedance spectroscopy(EIS)data fitting were respectively developed for epoxy coatings with and without pigments,based on their different water absorption behaviours.Power-law model was selected to evaluate the anti-permeability of epoxy varnish(EV)coating,which tends to form through pores in the coating structure.On the other hand,two-layer model based on Young theory was developed to evaluate the anti-permeability of pigmented epoxy coating.Consequently,the resistivity profile with coating thickness was calculated as a critical parameter to describe the anti-permeability of coating at different immersion time.The interpretation of water diffusion dynamics based on different coating structures was also given,which is responsible for the choice of distribution models.
基金Supported by the National High Technology Research and Development Program of China(Nos.2010AA09Z203, 2010AA065104), the National Natural Science Foundation of China(Nos.51003099, 51102219) and the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2012BAB 15B02).
文摘Anticorrosion epoxy coatings from Al and Zn based pigments were synthesized by adjusting their volume ratios, aiming at their increasing anticorrosion performances. The anticorrosion properties were examined via elec- trochemical impedance spectroscopy, Tafel polarization curve analysis and salt spray test. The coating morphologies before and after the salt spray tests were studied via scanning electron microscopy(SEM). The elemental and chemical compositions of the corroded surfaces of the coatings were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results indicate that the coating composed of Al/Zn at 10:1(volume ratio) displays the maximum anticorrosion performances, which are superior to those of pristine Al or Zn based pigment.
基金supported by the National Natural Science Foundation of China(Nos.51871227 and 52271079).
文摘Implantable electronic devices(IEDs)are widely used by human beings to achieve medical treatment and diagnosis nowadays.However,ideal encapsulation of IEDs is still far from perfect as full prevention of body fluid diffusion into the coating remains unsolved.Herein,we develop a high-performance composite coating for IED encapsulation by introducing SiO_(2) nanoparticles into silicone rubber,which synergistically enhances mechanical properties and improves barrier performance.By fabricating composite coatings with different nanosilica contents,3%nanosilica is proved to be an optimal additive content with an excellent combination of improved fracture strength(from 2.5 MPa to 4.5 MPa),increased coating resistance(from 10^(4) to 10^(9) cm^(2))and ideal coating uniformity.Mechanical and electrochemical characterizations subsequently confirm substantially enhanced mechanical properties and barrier performance of the composite coating,which effectively resist crack propagation and impede penetrations of water and chloride ions through the coating.Theoretical calculations further uncover that modified SiO_(2) particles with enriched methyl groups endow a strong bridging effect to interact with silicone rubber monomer,which,together with anti-agglomeration property of methyl groups,contributes to a pronounced improvement in mechanical performance of nanosilica-filled silicone rubber.Benefitting from the enhanced mechanical and barrier properties,the as-fabricated nanosilica-filled silicone rubber demonstrates superior protection for the encapsulated circuits with a significantly improved lifetime(709.1 h)compared to that of circuits coated by pure silicone rubber(472.8 h)and bare circuit boards(1 h),which offers great values for packaging material design in future IED encapsulation.