Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm ...Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.展开更多
In international thermonuclear experimental reactor (ITER), one of major concerns is an in-vessel tritium inventory from a point of safety. It is believed that the carbon-tritium co-deposited film produced by the er...In international thermonuclear experimental reactor (ITER), one of major concerns is an in-vessel tritium inventory from a point of safety. It is believed that the carbon-tritium co-deposited film produced by the erosion of carbon diverter walls has a high tritium concentration. However, no systematic evaluation for the tritium concentration has been conducted yet. In the present study, the carbon-hydrogen co-deposited films were prepared at the wall of pumping duct in Local Island Divertor experiments of LHD, in order to evaluate the tritium concentration of the co-deposited films produced in ITER. The hydrogen concentration was obtained by measuring the amount of retained hydrogen in the film and the mass density of the film. The hydrogen concentration of the co-deposited carbon film at the wall not facing to the plasma with a low temperature was extremely high, 1.3 in the atomic ratio of H/C. This value is triple times higher than the previous value obtained so far. The crystal structure of the co-deposited carbon film observed by Raman spectroscopy showed very unique structure (polymeric aC:H), which is well consistent with the high hydrogen concentration. The present study suggests that the tritium concentration of the co-deposited film in ITER depends on the wall position and becomes quite high as high as T/C-0.65. The results obtained contribute to evaluate the in-vessel tritium inventory owing to the co-deposited carbon films.展开更多
Electrodeposited Ni matrix/Al microparticles or nanoparticles dispersed composite coatings (termed as EMCCs or ENCCs) are developed from a Ni-based electrolyte bath. The Al microparticles are in a size range of 1 -5 ...Electrodeposited Ni matrix/Al microparticles or nanoparticles dispersed composite coatings (termed as EMCCs or ENCCs) are developed from a Ni-based electrolyte bath. The Al microparticles are in a size range of 1 -5 μm and the Al nanoparticles in an average size of 75 nm. The Al content in coatings increases with increase in the particle content in the bath. Particle size effect on the degree of codeposition is not significant. However, codeposition of Al nanoparticles instead of microparticles promotes more homogenous growth of Ni deposits on {111}, {200} and {220} planes. The oxidation at 1 050 ℃ of the as-deposited composite coatings shows that at a comparable Al content, ENCC of Ni-Al exhibits a better oxidation resistance than EMCC of Ni-Al due to the fast formation of an alumina scale during the transient stage of oxidation.展开更多
Zn-SnO2 composite coatings were prepared by direct potential using electrolytic co-deposition technique from sulfate solution. The effect of Zn2+ and SnO2 concentrations in deposited bath on the mechanical properties...Zn-SnO2 composite coatings were prepared by direct potential using electrolytic co-deposition technique from sulfate solution. The effect of Zn2+ and SnO2 concentrations in deposited bath on the mechanical properties and mor- phological characteristics of the composite coatings were examined. The characterizations of the sample were analyzed using scanning electron microscopy couple with energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD) and atomic force microscopy (AFM). The electrochemical degradation behavior of the samples in 3.65 wt.% NaCl solution was studied using potentiodynamic polarization technique and characterized by high-resolution optical microscope. From all the fabricated composite coatings, obvious diffraction peaks were observed with Zn-7Sn-S-0.3V film with Zn2Sn7, Sn, Zn2Sn5 and Zn phases, confirming the presence and formation of Zn-SnO2 coating. The XRD pattern shows that the presences of SnO2 particle remarkably play a major role in the precipitation and orientation of the alloy matrix. From the SEM/EDS and AFM results, the deposits show that composite particle and proper bath composition have strong influence on the microstructure. An enhanced corrosion resistance was attained as a result of the induced particles.展开更多
The composite coating has gained wider attention due to its property to protect materials used in energy, bridges, offshore platforms, underground pipelines, and the aviation industry from corrosion and deterioration....The composite coating has gained wider attention due to its property to protect materials used in energy, bridges, offshore platforms, underground pipelines, and the aviation industry from corrosion and deterioration. In this work, a literature review was conducted about the processes of nanocomposite coating, the mechanisms of electrolytic co-deposition, the texture of layers, and the residual stresses. An important aspect, residual stress, was emphasized, which represents the persistent stress after removing the external force affecting a metal in the plastic region. Because it cannot be measured directly and may be determined by measuring strain and indirect methods, the sources and methods for measuring residual stresses (XRD, SEM, TEM, EDS) were described in the last section to provide a comprehensive overview. Based on the thorough analysis of the published literature, it was concluded that nanoparticles could be electrodeposited with Ni on an Al substrate using a direct current and Ni sulfamate as an electrolytic solution, and Nickel will not reside on the oxide layer covering Al, so chemical changes are needed to prepare the Al surface. In addition, texture changes with the thickness of the coated layer must be investigated.展开更多
In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstruc...In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.展开更多
Mild steel is commonly used in the construction of Pipeline. The major problem of this Pipeline is corrosion. Effort is make my researchers to combat this problem. In this work Co-deposition of Ni-CoSiO_2 composite co...Mild steel is commonly used in the construction of Pipeline. The major problem of this Pipeline is corrosion. Effort is make my researchers to combat this problem. In this work Co-deposition of Ni-CoSiO_2 composite coating on mild steel was reported with the view to reduce this problem. The SiO_2 was varies from 5 to 25 wt% in the deposition. The microstructure, hardness values and potentiodynamic polarization in simulated sea water were determined. The results show that XRD pattern of the Ni Co deposited mild steel revealed the presence hard phases of NiO, Co_5Ni, Co_2Ni_3, Ni Co5 while that of Ni-CoSiO_2 deposited mild steel revealed the presence harder phases of NiOSiO_2, CoNi_7Si_2, Co_5Ni_2Si_3. The NiCo-25 SiO_2 deposited sample has smaller particle size than Ni-10 Co coating. Coating thickness of 110.7 mm was obtained for Ni-10 Co coating, while coating thickness of 135.7, 157.7, 165.0 mm were obtained at Ni-10 Co-x SiO_2(x=10, 15, 25 wt%). 99.90% corrosion resistance was achieved at Ni-Co-25 SiO_2. This improvement in corrosion resistance after composites coating could be attributed to the hard and fine structure obtained after coating.展开更多
Si-Al-Y co-deposition coatings were prepared on Ti-Al alloy by pack cementation processes at 1 050 ℃ for 4 h with different halide activators in the packs for enhancing the high temperature oxidation resistance of Ti...Si-Al-Y co-deposition coatings were prepared on Ti-Al alloy by pack cementation processes at 1 050 ℃ for 4 h with different halide activators in the packs for enhancing the high temperature oxidation resistance of Ti-Al alloy. The structure, constituent phases, formation process and oxidation behavior of the coatings were investigated. The experimental results showed that the coatings prepared respectively with NaF and NH_4Cl as activators were composed of a(Ti, X)_5Si_4,(Ti, X)_5Si_3(X represents Nb and Cr), and TiSi_2 outer layer, a TiAl_2 inner layer and an Al-rich interdiffusion zone. However, the constituent phases changed into TiSi_2 in the outer layer and(Ti, X)_5Si_4 and(Ti, X)_5Si_3 phases were observed in the middle layer of the coating prepared with AlCl_3·6H_2O activator. Among the halide activators studied, the coating prepared with AlCl_3·6H_2O was thicker and denser, which is the only suitable activator for pack Si-Al-Y co-deposition coatings on a Ti-Al alloy. The oxidation results show that the coating can protect the Ti-Al alloy from oxidation at 1000 ℃ in air for at least 80 h. The excellent oxidation resistance of the coating is attributed to the formation of a dense scale mainly consisted of TiO_2, SiO_2 and Al_2O_3.展开更多
Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the s...Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from (220) to (200). Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane (220) grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane (200) grew in the process of co-deposition. It was inferred that copper plane (200) was propitious to the deposition of submicron diamonds.展开更多
The Ti+C+N film was co-deposited on H13 steel by Filtered Vacuum Arc PlasmaDeposition (FVAPD) operated with a modified cathode. The co-deposited layer was effective for theimprovement of surface hardness and corrosion...The Ti+C+N film was co-deposited on H13 steel by Filtered Vacuum Arc PlasmaDeposition (FVAPD) operated with a modified cathode. The co-deposited layer was effective for theimprovement of surface hardness and corrosion resistance. The nano-hardness value of theco-deposited film is 1.3 times more than that of undeposited sample. The corrosion behaviormeasurement shows that the corrosion resistance for acid corrosion and pitting corrosion wasimproved greatly. It is owing to the formation of the new ternary ceramic phase TiC_(0.7) N_(0.3) inthe co-deposited layer. The mechanism of property improvement is discussed.展开更多
Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium ...Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium dodecyl sulfonate concentration were investigated.Electrochemical experiments demonstrate that iron's electrodeposition plays a leading role in the Ni-Fe co-deposition process,and the co-deposition nucleation mechanism accords with a progressive nucleation.Temperature increase does favor in increasing nickel content in the ferronickel(Ni-Fe co-deposition products),while Fe^(2+) concentration increase does not.When solution pH is higher than 3.5,nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe^(2+).With the current density of 180 A/m^2,Na_2SO_4 concentration of 100 g/L and Ni^(2+) concentration of 60 g/L,a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C,Fe^(2+) concentration of 0.3 g/L,solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.展开更多
Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique...Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy(EDXS), anode polarization curves, quasi-stationary polarization(Tafel) curves, electrochemical impedance spectroscopy(EIS), scanning electron microscopy(SEM), and X-ray diffraction(XRD). Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential(0.610 V at 500 A/m2) for oxygen evolution, the best electrocatalytic activity, the longest service life(360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2), and the lowest cell voltage(2.75 V at 500 A/m2). Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed.展开更多
The ultra high strength SiC particles (SiCp) reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were ana...The ultra high strength SiC particles (SiCp) reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O (5 nm) layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.展开更多
The reduction of Ni(Ⅱ) is an irreversible reaction and La(Ⅲ) cannot be reduced to La directly but be co-deposited inductively in the present of Ni(Ⅱ) in the Acetamide-Urea-NaBr molten salt electrolyte at 353 K. The...The reduction of Ni(Ⅱ) is an irreversible reaction and La(Ⅲ) cannot be reduced to La directly but be co-deposited inductively in the present of Ni(Ⅱ) in the Acetamide-Urea-NaBr molten salt electrolyte at 353 K. The uncrystallized alloy film of La-Ni is obtained by potentiostatic electrolysis, and the amount of La grows with increasing cathodic overpotential, molar ratios of La(Ⅲ) to Ni(Ⅱ) and the electrolysis time. The maximum amount of La in alloy film reaches to 78.81% (mass fraction) in present study.展开更多
Nickel-Ti O_2 hybrid catalysts are synthesized by electrodeposition and their catalytic activity with respect to the hydrogen evolution reaction is analyzed.Two types of titanium oxide particles,which are commercial p...Nickel-Ti O_2 hybrid catalysts are synthesized by electrodeposition and their catalytic activity with respect to the hydrogen evolution reaction is analyzed.Two types of titanium oxide particles,which are commercial particles of dense Ti O_2 and mesoporous TiO_2 particles synthesized by an aerosol method,are incorporated into the matrix of the nickel catalyst.Both nickel catalysts containing Ti O_2 particles presented higher catalytic activity than the conventional nickel Watts catalyst.Mesoporous TiO_2-modified nickel catalyst showed the highest catalytic activity towards HER in alkaline medium.In addition,this type of nickel catalyst increases its catalytic activity after ageing treatment,which is an indication of an increase in the electro-active area of the electrode.展开更多
Improvements of wear and corrosion properties are essential characteristic in engineering application. A study was made on the structure, electro-oxidation and properties of fabricated Zn-Al-SnO 2-Ti O2(Zn-Al-Sn-Ti)...Improvements of wear and corrosion properties are essential characteristic in engineering application. A study was made on the structure, electro-oxidation and properties of fabricated Zn-Al-SnO 2-Ti O2(Zn-Al-Sn-Ti) thin films using electrodeposition technique from chloride bath. The microstructural studies were performed by scanning electron microscopy with attached energy dispersive spectrometer(SEM-EDS), optical microscopy(OPM) and X-ray diffractogram(XRD). The electrochemical oxidation and erosion behavior in 3.65% Na Cl medium were studied by potentiodynamic polarization technique and characterized by atomic force microscopy(AFM). The hardness and wear behavior of the electrodeposited film were performed by high diamond dura scan microhardness tester and CERT UMT-2 reciprocating sliding machine. It was found that a successful co-deposition of composite and particle were attained. Homogeneous imbedded grain structure distribution and fine refinement of crystal with improved micromechanical behavior was achieved. The corrosion resistance, hardness and wear stability resistance of the fabricated quaternary films improved significantly in all varied process parameter.展开更多
A β-zeolite/polystyrene composite material was synthesized by co-deposition of mono-disperse polystyrene spheres and nano β-zeolite particles in aqueous suspension on a vertical substrate. Macro-porous β-zeolite wa...A β-zeolite/polystyrene composite material was synthesized by co-deposition of mono-disperse polystyrene spheres and nano β-zeolite particles in aqueous suspension on a vertical substrate. Macro-porous β-zeolite was obtained after the polystyrene template was removed by calcination. The micro/macro-pore structure of the prepared β-zeolite was highly ordered. In comparison with other assembly methods, the co-deposition method could obtain a highly ordered macro-porous material with relatively large zeolite filling particles, and therefore the co-deposition of particles with different size is a promising method for the fabrication of macro-porous materials.展开更多
Lithium(Li)metal batteries have long been deemed as the representative high-energy-density energy storage systems due to the ultrahigh theoretical capacity and lowest electrochemical potential of Li metal anode.Unfort...Lithium(Li)metal batteries have long been deemed as the representative high-energy-density energy storage systems due to the ultrahigh theoretical capacity and lowest electrochemical potential of Li metal anode.Unfortunately,the intractable dendritic Li deposition during cycling greatly restrains the large-scale applications of Li metal anodes.Recent advances have been explored to address this issue,among which a specific class of electrolyte additives for electroplating is deeply impressive,as they are economic and pragmatic.Different from the conventional additives that construct solid electrolyte interphase(SEI)layer on anodes,they make dendrite-free Li metal anodes feasible through altering Li plating behavior.In this research news article,the interlinked principles between industrial electroplating and Li deposition are firstly illustrated.The featured effects of electroplating additives on regulating Li plating morphology are also summarized and mainly divided into three categories:co-deposition with Li cation,coordination with Li cation,and leveling effect of Li films.Furthermore,the mechanism exploration or derivative use of electroplating additive for dendrite suppression and potential research directions are proposed,with emphasizing that industrial electroplating might enable Li metal anode to scalable battery techniques and spread to metal battery systems beyond Li.展开更多
The halide-activated pack cementation method is utilized to codeposit aluminum and silicon on Mo substrate. Emphasis is placed on the microstructure and elevated-temperature oxidation resistance of coatings. The resul...The halide-activated pack cementation method is utilized to codeposit aluminum and silicon on Mo substrate. Emphasis is placed on the microstructure and elevated-temperature oxidation resistance of coatings. The results show that hexagonal Mo(Si, Al)2 as a main phase and a little amount of the lower disilicide Mo5Si3 was formed on Mo substrate through the halide-activated pack cementation method. The resultant Si-Al coating on Mo substrate exhibits excellent cyclic oxidation resistance. The excellent cyclic oxidation resistance of the coatings is attributed to the formation of alumina on the coatings during the oxidation.展开更多
TiB2 - particulate- reinforced Ni3 Al composites were prepared by spray a tom-ization co-deposition technique. The reinforcement particulate can be uniformly distributedin matrix alloy, and no interaction would be fou...TiB2 - particulate- reinforced Ni3 Al composites were prepared by spray a tom-ization co-deposition technique. The reinforcement particulate can be uniformly distributedin matrix alloy, and no interaction would be found at interface between TiB, and Ni,Al.In a word, the composites possess comprehensive mechanical properties.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11874427 and 11804395)the Fundamental Research Funds for the Central Universities of Central South University (Grant No.2020zzts377)。
文摘Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.
文摘In international thermonuclear experimental reactor (ITER), one of major concerns is an in-vessel tritium inventory from a point of safety. It is believed that the carbon-tritium co-deposited film produced by the erosion of carbon diverter walls has a high tritium concentration. However, no systematic evaluation for the tritium concentration has been conducted yet. In the present study, the carbon-hydrogen co-deposited films were prepared at the wall of pumping duct in Local Island Divertor experiments of LHD, in order to evaluate the tritium concentration of the co-deposited films produced in ITER. The hydrogen concentration was obtained by measuring the amount of retained hydrogen in the film and the mass density of the film. The hydrogen concentration of the co-deposited carbon film at the wall not facing to the plasma with a low temperature was extremely high, 1.3 in the atomic ratio of H/C. This value is triple times higher than the previous value obtained so far. The crystal structure of the co-deposited carbon film observed by Raman spectroscopy showed very unique structure (polymeric aC:H), which is well consistent with the high hydrogen concentration. The present study suggests that the tritium concentration of the co-deposited film in ITER depends on the wall position and becomes quite high as high as T/C-0.65. The results obtained contribute to evaluate the in-vessel tritium inventory owing to the co-deposited carbon films.
文摘Electrodeposited Ni matrix/Al microparticles or nanoparticles dispersed composite coatings (termed as EMCCs or ENCCs) are developed from a Ni-based electrolyte bath. The Al microparticles are in a size range of 1 -5 μm and the Al nanoparticles in an average size of 75 nm. The Al content in coatings increases with increase in the particle content in the bath. Particle size effect on the degree of codeposition is not significant. However, codeposition of Al nanoparticles instead of microparticles promotes more homogenous growth of Ni deposits on {111}, {200} and {220} planes. The oxidation at 1 050 ℃ of the as-deposited composite coatings shows that at a comparable Al content, ENCC of Ni-Al exhibits a better oxidation resistance than EMCC of Ni-Al due to the fast formation of an alumina scale during the transient stage of oxidation.
基金supported financially by National Research Foundation and Surface Engineering Research Centre,Tshwane University of Technology,Pretoria,South Africa
文摘Zn-SnO2 composite coatings were prepared by direct potential using electrolytic co-deposition technique from sulfate solution. The effect of Zn2+ and SnO2 concentrations in deposited bath on the mechanical properties and mor- phological characteristics of the composite coatings were examined. The characterizations of the sample were analyzed using scanning electron microscopy couple with energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD) and atomic force microscopy (AFM). The electrochemical degradation behavior of the samples in 3.65 wt.% NaCl solution was studied using potentiodynamic polarization technique and characterized by high-resolution optical microscope. From all the fabricated composite coatings, obvious diffraction peaks were observed with Zn-7Sn-S-0.3V film with Zn2Sn7, Sn, Zn2Sn5 and Zn phases, confirming the presence and formation of Zn-SnO2 coating. The XRD pattern shows that the presences of SnO2 particle remarkably play a major role in the precipitation and orientation of the alloy matrix. From the SEM/EDS and AFM results, the deposits show that composite particle and proper bath composition have strong influence on the microstructure. An enhanced corrosion resistance was attained as a result of the induced particles.
文摘The composite coating has gained wider attention due to its property to protect materials used in energy, bridges, offshore platforms, underground pipelines, and the aviation industry from corrosion and deterioration. In this work, a literature review was conducted about the processes of nanocomposite coating, the mechanisms of electrolytic co-deposition, the texture of layers, and the residual stresses. An important aspect, residual stress, was emphasized, which represents the persistent stress after removing the external force affecting a metal in the plastic region. Because it cannot be measured directly and may be determined by measuring strain and indirect methods, the sources and methods for measuring residual stresses (XRD, SEM, TEM, EDS) were described in the last section to provide a comprehensive overview. Based on the thorough analysis of the published literature, it was concluded that nanoparticles could be electrodeposited with Ni on an Al substrate using a direct current and Ni sulfamate as an electrolytic solution, and Nickel will not reside on the oxide layer covering Al, so chemical changes are needed to prepare the Al surface. In addition, texture changes with the thickness of the coated layer must be investigated.
基金Project(2014JZ012)supported by the Natural Science Program for Basic Research in Key Areas of Shaanxi Province,China
文摘In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.
文摘Mild steel is commonly used in the construction of Pipeline. The major problem of this Pipeline is corrosion. Effort is make my researchers to combat this problem. In this work Co-deposition of Ni-CoSiO_2 composite coating on mild steel was reported with the view to reduce this problem. The SiO_2 was varies from 5 to 25 wt% in the deposition. The microstructure, hardness values and potentiodynamic polarization in simulated sea water were determined. The results show that XRD pattern of the Ni Co deposited mild steel revealed the presence hard phases of NiO, Co_5Ni, Co_2Ni_3, Ni Co5 while that of Ni-CoSiO_2 deposited mild steel revealed the presence harder phases of NiOSiO_2, CoNi_7Si_2, Co_5Ni_2Si_3. The NiCo-25 SiO_2 deposited sample has smaller particle size than Ni-10 Co coating. Coating thickness of 110.7 mm was obtained for Ni-10 Co coating, while coating thickness of 135.7, 157.7, 165.0 mm were obtained at Ni-10 Co-x SiO_2(x=10, 15, 25 wt%). 99.90% corrosion resistance was achieved at Ni-Co-25 SiO_2. This improvement in corrosion resistance after composites coating could be attributed to the hard and fine structure obtained after coating.
基金the Key Scientific Research Projects in 2017 at North Minzu University(2017KJ05)
文摘Si-Al-Y co-deposition coatings were prepared on Ti-Al alloy by pack cementation processes at 1 050 ℃ for 4 h with different halide activators in the packs for enhancing the high temperature oxidation resistance of Ti-Al alloy. The structure, constituent phases, formation process and oxidation behavior of the coatings were investigated. The experimental results showed that the coatings prepared respectively with NaF and NH_4Cl as activators were composed of a(Ti, X)_5Si_4,(Ti, X)_5Si_3(X represents Nb and Cr), and TiSi_2 outer layer, a TiAl_2 inner layer and an Al-rich interdiffusion zone. However, the constituent phases changed into TiSi_2 in the outer layer and(Ti, X)_5Si_4 and(Ti, X)_5Si_3 phases were observed in the middle layer of the coating prepared with AlCl_3·6H_2O activator. Among the halide activators studied, the coating prepared with AlCl_3·6H_2O was thicker and denser, which is the only suitable activator for pack Si-Al-Y co-deposition coatings on a Ti-Al alloy. The oxidation results show that the coating can protect the Ti-Al alloy from oxidation at 1000 ℃ in air for at least 80 h. The excellent oxidation resistance of the coating is attributed to the formation of a dense scale mainly consisted of TiO_2, SiO_2 and Al_2O_3.
文摘Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from (220) to (200). Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane (220) grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane (200) grew in the process of co-deposition. It was inferred that copper plane (200) was propitious to the deposition of submicron diamonds.
基金This work was supported by Committee 863 High Science & Technology (217003) and The National Natural Science Foundation of China (Grant No.50141022).
文摘The Ti+C+N film was co-deposited on H13 steel by Filtered Vacuum Arc PlasmaDeposition (FVAPD) operated with a modified cathode. The co-deposited layer was effective for theimprovement of surface hardness and corrosion resistance. The nano-hardness value of theco-deposited film is 1.3 times more than that of undeposited sample. The corrosion behaviormeasurement shows that the corrosion resistance for acid corrosion and pitting corrosion wasimproved greatly. It is owing to the formation of the new ternary ceramic phase TiC_(0.7) N_(0.3) inthe co-deposited layer. The mechanism of property improvement is discussed.
基金Project(51574135)supported by the National Natural Science Foundation of ChinaProject(KKPT201563022)supported by Collaborative Innovation Center of Kunming University of Science and Technology,China
文摘Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium dodecyl sulfonate concentration were investigated.Electrochemical experiments demonstrate that iron's electrodeposition plays a leading role in the Ni-Fe co-deposition process,and the co-deposition nucleation mechanism accords with a progressive nucleation.Temperature increase does favor in increasing nickel content in the ferronickel(Ni-Fe co-deposition products),while Fe^(2+) concentration increase does not.When solution pH is higher than 3.5,nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe^(2+).With the current density of 180 A/m^2,Na_2SO_4 concentration of 100 g/L and Ni^(2+) concentration of 60 g/L,a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C,Fe^(2+) concentration of 0.3 g/L,solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.
基金Projects(51004056,51004057)supported by the National Natural Science Foundation of ChinaProject(KKZ6201152009)supported by the Opening Foundation of Key Laboratory of Inorganic Coating Materials,Chinese Academy of Sciences+2 种基金Project(2010ZC052)supported by the Applied Basic Research Foundation of Yunnan Province,ChinaProject(20125314110011)supported by the Specialized Research Fund for the Doctoral Program of Higher Education,ChinaProject(2010247)supported by Analysis&Testing Foundation of Kunming University of Science and Technology,China
文摘Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy(EDXS), anode polarization curves, quasi-stationary polarization(Tafel) curves, electrochemical impedance spectroscopy(EIS), scanning electron microscopy(SEM), and X-ray diffraction(XRD). Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential(0.610 V at 500 A/m2) for oxygen evolution, the best electrocatalytic activity, the longest service life(360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2), and the lowest cell voltage(2.75 V at 500 A/m2). Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed.
基金Project (02Gky2004) supported by Hunan Provincial Science and Technology Department, China
文摘The ultra high strength SiC particles (SiCp) reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O (5 nm) layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.
文摘The reduction of Ni(Ⅱ) is an irreversible reaction and La(Ⅲ) cannot be reduced to La directly but be co-deposited inductively in the present of Ni(Ⅱ) in the Acetamide-Urea-NaBr molten salt electrolyte at 353 K. The uncrystallized alloy film of La-Ni is obtained by potentiostatic electrolysis, and the amount of La grows with increasing cathodic overpotential, molar ratios of La(Ⅲ) to Ni(Ⅱ) and the electrolysis time. The maximum amount of La in alloy film reaches to 78.81% (mass fraction) in present study.
基金financial support from "Agencia Nacional de Promoción Científica y Tecnológica" (PICT 1818)CONICET (PIP 112 201301 00808)
文摘Nickel-Ti O_2 hybrid catalysts are synthesized by electrodeposition and their catalytic activity with respect to the hydrogen evolution reaction is analyzed.Two types of titanium oxide particles,which are commercial particles of dense Ti O_2 and mesoporous TiO_2 particles synthesized by an aerosol method,are incorporated into the matrix of the nickel catalyst.Both nickel catalysts containing Ti O_2 particles presented higher catalytic activity than the conventional nickel Watts catalyst.Mesoporous TiO_2-modified nickel catalyst showed the highest catalytic activity towards HER in alkaline medium.In addition,this type of nickel catalyst increases its catalytic activity after ageing treatment,which is an indication of an increase in the electro-active area of the electrode.
基金supported financially by the National Research Foundationsupported by Surface Engineering Research Centre (SERC),Tshwane University of Technology
文摘Improvements of wear and corrosion properties are essential characteristic in engineering application. A study was made on the structure, electro-oxidation and properties of fabricated Zn-Al-SnO 2-Ti O2(Zn-Al-Sn-Ti) thin films using electrodeposition technique from chloride bath. The microstructural studies were performed by scanning electron microscopy with attached energy dispersive spectrometer(SEM-EDS), optical microscopy(OPM) and X-ray diffractogram(XRD). The electrochemical oxidation and erosion behavior in 3.65% Na Cl medium were studied by potentiodynamic polarization technique and characterized by atomic force microscopy(AFM). The hardness and wear behavior of the electrodeposited film were performed by high diamond dura scan microhardness tester and CERT UMT-2 reciprocating sliding machine. It was found that a successful co-deposition of composite and particle were attained. Homogeneous imbedded grain structure distribution and fine refinement of crystal with improved micromechanical behavior was achieved. The corrosion resistance, hardness and wear stability resistance of the fabricated quaternary films improved significantly in all varied process parameter.
基金the National Basic Research Program of China (No. 2004CB217808) the National Natural Science Foundation of China (No. 20376046).
文摘A β-zeolite/polystyrene composite material was synthesized by co-deposition of mono-disperse polystyrene spheres and nano β-zeolite particles in aqueous suspension on a vertical substrate. Macro-porous β-zeolite was obtained after the polystyrene template was removed by calcination. The micro/macro-pore structure of the prepared β-zeolite was highly ordered. In comparison with other assembly methods, the co-deposition method could obtain a highly ordered macro-porous material with relatively large zeolite filling particles, and therefore the co-deposition of particles with different size is a promising method for the fabrication of macro-porous materials.
基金support from National Nature Science Foundation of China(Grant No.51872157)Shenzhen Technical Plan Project(Grant Nos.JCYJ20170412170911187 and JCYJ20170817161753629)+1 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(Grant No.2017BT01N111)Guangdong Technical Plan Project(Grant No.2017B090907005)
文摘Lithium(Li)metal batteries have long been deemed as the representative high-energy-density energy storage systems due to the ultrahigh theoretical capacity and lowest electrochemical potential of Li metal anode.Unfortunately,the intractable dendritic Li deposition during cycling greatly restrains the large-scale applications of Li metal anodes.Recent advances have been explored to address this issue,among which a specific class of electrolyte additives for electroplating is deeply impressive,as they are economic and pragmatic.Different from the conventional additives that construct solid electrolyte interphase(SEI)layer on anodes,they make dendrite-free Li metal anodes feasible through altering Li plating behavior.In this research news article,the interlinked principles between industrial electroplating and Li deposition are firstly illustrated.The featured effects of electroplating additives on regulating Li plating morphology are also summarized and mainly divided into three categories:co-deposition with Li cation,coordination with Li cation,and leveling effect of Li films.Furthermore,the mechanism exploration or derivative use of electroplating additive for dendrite suppression and potential research directions are proposed,with emphasizing that industrial electroplating might enable Li metal anode to scalable battery techniques and spread to metal battery systems beyond Li.
文摘The halide-activated pack cementation method is utilized to codeposit aluminum and silicon on Mo substrate. Emphasis is placed on the microstructure and elevated-temperature oxidation resistance of coatings. The results show that hexagonal Mo(Si, Al)2 as a main phase and a little amount of the lower disilicide Mo5Si3 was formed on Mo substrate through the halide-activated pack cementation method. The resultant Si-Al coating on Mo substrate exhibits excellent cyclic oxidation resistance. The excellent cyclic oxidation resistance of the coatings is attributed to the formation of alumina on the coatings during the oxidation.
文摘TiB2 - particulate- reinforced Ni3 Al composites were prepared by spray a tom-ization co-deposition technique. The reinforcement particulate can be uniformly distributedin matrix alloy, and no interaction would be found at interface between TiB, and Ni,Al.In a word, the composites possess comprehensive mechanical properties.