Showing papers on "Coating published in 2011"
TL;DR: The application of conducting polymer to minimize the diffusion of polysulfides out of the mesoporous carbon matrix by coating poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) onto mesoporus carbon/sulfur particles.
Abstract: Rechargeable lithium–sulfur (Li–S) batteries hold great potential for next-generation high-performance energy storage systems because of their high theoretical specific energy, low materials cost, and environmental safety. One of the major obstacles for its commercialization is the rapid capacity fading due to polysulfide dissolution and uncontrolled redeposition. Various porous carbon structures have been used to improve the performance of Li–S batteries, as polysulfides could be trapped inside the carbon matrix. However, polysulfides still diffuse out for a prolonged time if there is no effective capping layer surrounding the carbon/sulfur particles. Here we explore the application of conducting polymer to minimize the diffusion of polysulfides out of the mesoporous carbon matrix by coating poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) onto mesoporous carbon/sulfur particles. After surface coating, coulomb efficiency of the sulfur electrode was improved from 93% to 97%, and capaci...
815 citations
TL;DR: It is indicated that the deposition behavior of pDA is not strongly dependent on the nature of the substrates, and effective strategies for exploiting the properties of dopamine to create novel functional polymer materials are found.
Abstract: This study aims to explore the fundamental surface characteristics of polydopamine (pDA)-coated hydrophobic polymer films. A poly(vinylidene fluoride) (PVDF) film was surface modified by dip coating in an aqueous solution of dopamine on the basis of its self-polymerization and strong adhesion feature. The self-polymerization and deposition rates of dopamine on film surfaces increased with increasing temperature as evaluated by both spectroscopic ellipsometry and scanning electronic microscopy (SEM). Changes in the surface morphologies of pDA-coated films as well as the size and shape of pDA particles in the solution were also investigated by SEM, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The surface roughness and surface free energy of pDA-modified films were mainly affected by the reaction temperature and showed only a slight dependence on the reaction time and concentration of the dopamine solution. Additionally, three other typical hydrophobic polymer films of polytetrafluoroethylene (PTFE), poly(ethylene terephthalate) (PET), and polyimide (PI) were also modified by the same procedure. The lyophilicity (liquid affinity) and surface free energy of these polymer films were enhanced significantly after being coated with pDA, as were those of PVDF films. It is indicated that the deposition behavior of pDA is not strongly dependent on the nature of the substrates. This information provides us with not only a better understanding of biologically inspired surface chemistry for pDA coatings but also effective strategies for exploiting the properties of dopamine to create novel functional polymer materials.
628 citations
TL;DR: In this article, the authors reviewed the tribological advancement of different electroless nickel coatings based on the bath types, structure and also the tribo testing parameters in recent years.
477 citations
TL;DR: It is found that this specially structured robust coating was extremely effective in resisting biofilm formation, and that the biofilm resistance depended on the nature of conjugated peptides.
365 citations
TL;DR: In this article, the surface of the nanoparticles was treated with amino propyl trimethoxy silane (APS) to achieve proper dispersion of nanoparticles in the epoxy-based coating and making possible chemical interactions between nanoparticles and polymeric coating.
362 citations
TL;DR: MAO showed beneficial effects on the corrosion resistance of, and thus improved cell adhesion to, the Mg-Ca alloy, and should be a good surface modification method for other biomedical magnesium alloys.
340 citations
TL;DR: In this paper, a life cycle analysis was performed on a full roll-to-roll coating procedure used for the manufacture of flexible polymer solar cell modules, and the results showed that an Energy Pay-Back Time (EPBT) of 2.02 years can be achieved for an organic solar module of 2% efficiency, which could be reduced to 1.35 years, if the efficiency was 3%.
325 citations
TL;DR: A new fabrication strategy of the graphene-coated solid-phase microextraction (SPME) fiber is developed, and the obtained fiber was stable enough for more than 150 replicate extraction cycles and exhibited higher enrichment factors (EFs) than the commercial polydimethylsioxane (PDMS) fiber.
Abstract: A new fabrication strategy of the graphene-coated solid-phase microextraction (SPME) fiber is developed. Graphite oxide was first used as starting coating material that covalently bonded to the fused-silica substrate using 3-aminopropyltriethoxysilane (APTES) as cross-linking agent and subsequently deoxidized by hydrazine to give the graphene coating in situ. The chemical bonding between graphene and the silica fiber improve its chemical stability, and the obtained fiber was stable enough for more than 150 replicate extraction cycles. The graphene coating was wrinkled and folded, like the morphology of the rough tree bark. Its performance is tested by headspace (HS) SPME of polycyclic aromatic hydrocarbons (PAHs) followed by GC/MS analysis. The results showed that the graphene-coated fiber exhibited higher enrichment factors (EFs) from 2-fold for naphthalene to 17-fold for B(b)FL as compared to the commercial polydimethylsioxane (PDMS) fiber, and the EFs increased with the number of condensed rings of PAHs. The strong adsorption affinity was believed to be mostly due to the dominant role of π-π stacking interaction and hydrophobic effect, according to the results of selectivity study for a variety of organic compounds including PAHs, the aromatic compounds with different substituent groups, and some aliphatic hydrocarbons. For PAHs analysis, the graphene-coated fiber showed good precision (<11%), low detection limits (1.52-2.72 ng/L), and wide linearity (5-500 ng/L) under the optimized conditions. The repeatability of fiber-to-fiber was 4.0-10.8%. The method was applied to simultaneous analysis of eight PAHs with satisfactory recoveries, which were 84-102% for water samples and 72-95% for soil samples, respectively.
306 citations
TL;DR: Results suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect is suggested, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell.
Abstract: This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol−gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g−1), narrow pore size distribution (d ∼ 3 nm), and large pore volume (∼1 mL·g−1). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol−gel coating was observed during a simulated corrosion process by the ...
299 citations
TL;DR: In this paper, the performance of several conversion coating technologies is reviewed and the assessment of performance based on the literature to date, thermodynamic analysis has been used to compare coating processes.
Abstract: The corrosion susceptibility of Mg and its alloys in humid and aqueous environments limits their widespread application. The performance of several conversion coating technologies is reviewed herein. In addition to the assessment of performance based on the literature to date, thermodynamic analysis has been used to compare coating processes. Ongoing research reveals that the search for appropriate conversion coatings to replace toxic Cr-based coatings continues. It is seen that the variability between coatings of the same technology was greater than the averages between coating technologies. Additionally, coating pretreatment also appears to be more significant than the choice of coating technology itself.
297 citations
TL;DR: In this article, the authors highlight the recent progress made by tuning the processing conditions beyond conventional ranges to prepare more and more complex and controlled nanostructured layers, and demonstrate that dip-coating is also a well suited method to impregnate porosity, to make nanocomposites, or to perform nanocasting.
Abstract: Dip-coating is an ideal method to prepare thin layers from chemical solutions since it is a low-cost and waste-free process that is easy to scale up and offers a good control on thickness. For such reasons, it is becoming more and more popular not only in research and development laboratories, but also in industrial production, as testified by the increasing number of annual publications (9, 180, and 480 articles in 1990, 2000, and 2010, respectively). Even so, the full potential of dip-coating has not yet been fully explored and exploited. This article highlights the recent progresses made by tuning the processing conditions beyond conventional ranges to prepare more and more complex and controlled nanostructured layers. Especially, we will see how one can take advantage of an accurate tuning of the withdrawal speed and of the atmosphere to control the nanostructuration originating from evaporation-induced-self-assembly (EISA), together with the final thickness from a few nm up to 1 μm from the same initial solution. A new regime of deposition, involving capillary induced convective coating that is highly suitable for the deposition from aqueous and/or highly diluted solutions, will be described. Finally, it will be demonstrated that dip-coating is also a well suited method to impregnate porosity, to make nanocomposites, or to perform nanocasting. The present discussion is illustrated with systems of interests in domains such as optics, energies, nanoelectronics, nanofluidics, etc.
TL;DR: A superhydrophobic xerogel coating synthesized from a mixture of nanostructured fluorinated silica colloids, fluoroalkoxysilane, and a backbone silane is reported, making it an ideal candidate as a biopassivation strategy.
Abstract: A superhydrophobic xerogel coating synthesized from a mixture of nanostructured fluorinated silica colloids, fluoroalkoxysilane, and a backbone silane is reported. The resulting fluorinated surface was characterized using contact angle goniometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Quantitative bacterial adhesion studies performed using a parallel plate flow cell demonstrated that the adhesion of Staphylococcus aureus and Pseudomonas aeruginosa was reduced by 2.08 ± 0.25 and 1.76 ± 0.12 log over controls, respectively. This simple superhydrophobic coating synthesis may be applied to any surface, regardless of geometry, and does not require harsh synthesis or processing conditions, making it an ideal candidate as a biopassivation strategy.
TL;DR: In this article, a method for the construction of the window of deposition and the selection of optimum process parameters is presented for cold spraying, where particle impact velocity and the critical particle velocity for bonding are worked out and expressed explicitly in terms of key process and material parameters.
Abstract: For cold spraying, a method for the construction of the window of deposition and the selection of optimum process parameters is presented. Initially, particle impact velocity and the critical particle velocity for bonding are worked out and expressed explicitly in terms of key process and material parameters. Subsequently, the influence of particle velocity on coating characteristics is examined in view of the results of experiments and simulations. It has been found that main coating characteristics can be described as a unique function of the ratio of particle velocity to critical velocity, here referred to as η. Finally, coating properties are linked directly to primary process parameters via parameter selection maps, where contours of constant η are plotted on a plane of gas temperature versus gas pressure. Inferences of the presented method and the resulting parameter selection maps are discussed for the example of copper as feedstock material.
TL;DR: A nonwoven fabric with paperlike qualities composed of silicon nanowires is reported, useful as a self-supporting, mechanically flexible, high-energy-storage anode material in a lithium ion battery.
Abstract: A nonwoven fabric with paperlike qualities composed of silicon nanowires is reported. The nanowires, made by the supercritical-fluid–liquid–solid process, are crystalline, range in diameter from 10 to 50 nm with an average length of >100 μm, and are coated with a thin chemisorbed polyphenylsilane shell. About 90% of the nanowire fabric volume is void space. Thermal annealing of the nanowire fabric in a reducing environment converts the polyphenylsilane coating to a carbonaceous layer that significantly increases the electrical conductivity of the material. This makes the nanowire fabric useful as a self-supporting, mechanically flexible, high-energy-storage anode material in a lithium ion battery. Anode capacities of more than 800 mA h g–1 were achieved without the addition of conductive carbon or binder.
TL;DR: In this article, a new composite separator for a lithium-ion battery was proposed by incorporating SiO 2 nanoparticles and polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) binders.
TL;DR: In this article, the authors investigated the influence of Si (1.2 ) and Mn (1 2 ) on the microstructure, properties and coating quality of laser cladded FeCoNiCrCu high-entropy alloy coating.
TL;DR: In this paper, a spherical colloid with a nematic liquid crystal is used to control the number and orientation of the defects in the crystal, which could be useful for engineering the microstructure of colloidal materials.
Abstract: Coating a spherical colloid with a nematic liquid crystal causes frustration-induced defects in the crystal. The thickness of this coating can be used to systematically control the number and orientation of these defects, which could be useful for engineering the microstructure of colloidal materials.
TL;DR: In this article, an electro-etched carbon fiber cloth is explored as an electrode for super-capacitors by coating polyaniline nanowires, which can reach a mass-normalized specific capacitance of 673 F/g and an area-normalised specific capacity of 3.5 F/cm2.
Abstract: Carbon fiber clothes are a promising material for electrodes of supercapacitors owing to their unique 3-D structure, high surface area, remarkable chemical stability, and electrical conductivity. In this Article, electro-etched carbon fiber cloth is explored as an electrode for supercapacitors by coating polyaniline nanowires. The as-prepared electro-etched carbon fiber cloth and polyaniline nanowires, which were characterized by scanning electron microscopy and transmission electron microscopy, were assembled into supercapacitors. The polyaniline nanowires can reach a mass-normalized specific capacitance of 673 F/g and an area-normalized specific capacitance of 3.5 F/cm2. We also studied the etching and coating of single carbon fibers using the same processing method. The single fiber shows almost the same specific capacitance as the carbon fiber cloth of the same coating density, indicating good accessibility of etched carbon fiber cloth electrode. This work suggests that our polyaniline-based etched ca...
TL;DR: In this article, the surface of Li(Ni1/3Mn 1/3Co/3 Co/3)O2 particles are coated with thin conformal layers of Al2O3 by atomic layer deposition (ALD).
TL;DR: In this article, a carbon-doped titanium dioxide (TiO2) coating on multiwalled carbon nanotubes (MWCNTs) was prepared by oxidation of titanium carbide (TiC) coated MWCNTs.
Abstract: Carbon-doped titanium dioxide (TiO2) coating on multiwalled carbon nanotubes (MWCNTs) was prepared by oxidation of titanium carbide (TiC) coated MWCNTs. The structure, morphology and surface chemistry states of the TiO2 coating on MWCNTs were characterized by XRD, SEM, HRTEM and XPS. The results suggest that the TiO2 coated MWCNTs keep the similar morphology and length with the pristine MWCNTs. The TiO2 coating, composed of homogeneous nanosized particles, contacts closely with MWCNTs via chemistry bond and Ti–O–C bonds are found. The visible light photocatalytic activity of the prepared photocatalyst was evaluated by decomposition of methylene blue aqueous solution. A probable mechanism of TiO2 and MWCNTs on the enhancement of visible light performance is proposed. It suggests that MWCNTs play key roles, which may act as a support, absorbent, photo-generated transfer station and carbon-doping source.
TL;DR: Preparation of a highly crystalline nano hydroxyapatite (HA) coating on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray and their in vitro and in vivo biological response are reported.
Abstract: This paper reports preparation of a highly crystalline nano hydroxyapatite (HA) coating on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray and their in vitro and in vivo biological response. HA coatings were prepared on Ti using normal and supersonic plasma nozzles at different plate powers and working distances. X-ray diffraction (XRD) and Fourier transformed infrared spectroscopic (FTIR) analysis show that the normal plasma nozzle lead to increased phase decomposition, high amorphous calcium phosphate (ACP) phase formation, and severe dehydroxylation of HA. In contrast, coatings prepared using supersonic nozzle retained the crystallinity and phase purity of HA due to relatively short exposure time of HA particles in the plasma. In addition, these coatings exhibited a microstructure that varied from porous and glassy structure at the coating-substrate interface to dense HA at the top surface. The microstructural analysis showed that the coating was made of multigrain HA particles of ~200 nm in size, which consisted of recrystallized HA grains in the size range of 15- 20 nm. Apart from the type of nozzle, working distance was also found to have a strong influence on the HA phase decomposition, while plate power had little influence. Depending on the plasma processing conditions, a coating thickness between 300 and 400 μm was achieved where the adhesive bond strengths were found to be between 4.8 MPa to 24 MPa. The cytotoxicity of HA coatings was examined by culturing human fetal osteoblast cells (hFOB) on coated surfaces. In vivo studies, using the cortical defect model in rat femur, evaluated the histological response of the HA coatings prepared with supersonic nozzle. After 2 weeks of implantation, osteoid formation was evident on the HA coated implant surface, which could indicate early implant- tissue integration in vivo.
TL;DR: In this article, a high thermal conductivity of 493 Wm−m−1 K−1 was achieved in the Cu/Ti-coated diamond composites, attributed to the 285nm thick Ti coating.
TL;DR: In this paper, the microstructure and corrosion resistance of Fe-based amorphous coatings with a composition of Fe 49.7 Cr 18 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2.4 have been prepared on a mild steel substrate by HVAF and HVOF processes.
TL;DR: In this article, the anti-corrosion properties of thin (10, 50 and 100 nm) alumina coatings grown by atomic layer deposition at 160°C on steel is reported.
TL;DR: Geopolymer-type coatings prepared by using an industrially available sodium silicate solution (SiO2:Na2O = 3.1) and metakaolin were applied to steel substrates as mentioned in this paper.
Abstract: Geopolymer-type coatings prepared by using an industrially available sodium silicate solution (SiO2:Na2O = 3.1) and metakaolin were applied to steel substrates. The coatings exhibited excellent adhesion to steel substrates achieving greater than 3.5 MPa tensile stress. Dissolution of the coating in water after 72 h of static testing varied between 12.8 and 34.5 wt.% depending on the water content of initial formulations. Coating formulations showed up to 3% thermal expansion after heating to 800 °C. Coatings maintained high structural integrity with steel substrates when subjected to a heat treatment by a gas torch and formulations calcined at 1000 °C for 1 h showed an X-ray amorphous structure.
TL;DR: In this article, the authors presented two spray techniques used for manufacturing nanostructured coatings: thermal plasma and HVOF sensors developed for in-flight diagnostics of micrometre-sized particles and the interaction of a liquid and hot gas flow.
Abstract: From the pioneering works of McPherson in 1973 who identified nanometre-sized features in thermal spray conventional alumina coatings (using sprayed particles in the tens of micrometres size range) to the most recent and most advanced work aimed at manufacturing nanostructured coatings from nanometre-sized feedstock particles, the thermal spray community has been involved with nanometre-sized features and feedstock for more than 30 years.Both the development of feedstock (especially through cryo-milling, and processes able to manufacture coatings structured at the sub-micrometre or nanometre sizes, such as micrometre-sized agglomerates made of nanometre-sized particles for feedstock) and the emergence of thermal spray processes such as suspension and liquid precursor thermal spray techniques have been driven by the need to manufacture coatings with enhanced properties. These techniques result in two different types of coatings: on the one hand, those with a so-called bimodal structure having nanometre-sized zones embedded within micrometre ones, for which the spray process is similar to that of conventional coatings and on the other hand, sub-micrometre or nanostructured coatings achieved by suspension or solution spraying. Compared with suspension spraying, solution precursor spraying uses molecularly mixed precursors as liquids, avoiding a separate processing route for the preparation of powders and enabling the synthesis of a wide range of oxide powders and coatings. Such coatings are intended for use in various applications ranging from improved thermal barrier layers and wear-resistant surfaces to thin solid electrolytes for solid oxide fuel cell systems, among other numerous applications.Meanwhile these processes are more complex to operate since they are more sensitive to parameter variations compared with conventional thermal spray processes. Progress in this area has resulted from the unique combination of modelling activities, the evolution of diagnostic tools and strategies, and experimental advances that have enabled the development of a wide range of coating structures exhibiting in numerous cases unique properties. Several examples are detailed. In this paper the following aspects are presented successively (i) the two spray techniques used for manufacturing such coatings: thermal plasma and HVOF, (ii) sensors developed for in-flight diagnostics of micrometre-sized particles and the interaction of a liquid and hot gas flow, (iii) three spray processes: conventional spraying using micrometre-sized agglomerates of nanometre-sized particles, suspension spraying and solution spraying and (iv) the emerging issues resulting from the specific structures of these materials, particularly the characterization of these coatings and (v) the potential industrial applications.Further advances require the scientific and industrial communities to undertake new research and development activities to address, understand and control the complex mechanisms occurring, in particular, thermal flow?liquid drops or stream interactions when considering suspension and liquid precursor thermal spray techniques. Work is still needed to develop new measurement devices to diagnose in-flight droplets or particles below 2??m average diameter and to validate that the assumptions made for liquid?hot gas interactions.Efforts are also required to further develop some of the characterization protocols suitable to address the specificities of such nanostructured coatings, as some existing 'conventional' protocols usually implemented on thermal spray coatings are not suitable anymore, in particular to address the void network architectures from which numerous coatings properties are derived.
TL;DR: In this paper, a laser-clad high entropy alloy coating was applied on Ti-6Al-4V alloy by laser cladding and the phase equilibrium of the coating material was calculated using the CALPHAD method.
Abstract: TiVCrAlSi high entropy alloy coatings were deposited on Ti–6Al–4V alloy by laser cladding. SEM, XRD and EDS analyses show that, the as-clad coating is composed of (Ti,V) 5 Si 3 and a BCC solid solution. After annealing at 800 °C for 24 h under vacuum, the coating is composed of (Ti,V) 5 Si 3 , Al 8 (V,Cr) 5 , and a BCC solid solution. The temperature-dependent phase equilibrium for the coating material calculated by using the CALPHAD method, indicates that above 880 °C the stable phases existing in the coating material are a BCC solid-solution and (Ti,V) 5 Si 3 . When the temperature is below 880 °C, the stable phases are (Ti,V) 5 Si 3 , Al 8 (V,Cr) 5 , and a BCC solid solution. In order to validate the calculation results, they were compared with TiVCrAlSi alloy samples prepared by arc melting, encapsulated in quartz tubes under vacuum, annealed at 400–1100 °C for 3 days and water-quenched. XRD analysis shows that the experimental phase composition agrees with the thermodynamic calculations. After vacuum annealing, there is a small increase of hardness for the laser clad TiVCrAlSi coating, which is due to the formation of Al 8 (V,Cr) 5 . The oxidation tests show that the TiVCrAlSi coating effectively improves the oxidation resistance of Ti–6Al–4V at 800 °C in air. The formation of a dense and adherent scale consisting of SiO 2 , Cr 2 O 3 , TiO 2 , Al 2 O 3 and a small amount of V 2 O 5 is supposed to be responsible for the observed improvement of the oxidation resistance.
TL;DR: In this paper, the residual stress profiles in Cu and Al coatings cold sprayed using kinetic metallization have been studied using neutron diffraction, and the measured profiles were fit to Tsui and Clyne's progressive coating deposition model, which demonstrated that residual stresses are largely due to kinetic and not thermal effects.
TL;DR: In this article, a rapid in situ chemical oxidation polymerization of polyaniline was carried out to coat MWCNT core/sulfur-shell structures, which were obtained by ball-milling and thermal treatment.
Abstract: Rapid in situ chemical oxidation polymerization of polyaniline was carried out to coat MWCNT-core/sulfur-shell structures. The S-coated-MWCNTs were obtained by ball-milling and thermal treatment. T...
TL;DR: In this paper, the surface of titanium dioxide (TiO 2 ) nanoparticles was modified with γ-aminopropyltriethoxy silane as a coupling agent.