Magnetic vortex state and multi-domain pattern in electrodeposited hemispherical nanogranular nickel films

International Nuclear Information System (INIS)

Samardak, Alexander; Sukovatitsina, Ekaterina; Ognev, Alexey; Stebliy, Maksim; Davydenko, Alexander; Chebotkevich, Ludmila; Keun Kim, Young; Nasirpouri, Forough; Janjan, Seyed-Mehdi; Nasirpouri, Farzad

2014-01-01

Magnetic states of nickel nanogranular films were studied in two distinct structures of individual and agglomerated granules electrodeposited on n-type Si(1 1 1) surface from a modified Watts bath at a low pH of 2. Magnetic force microscopy and micromagnetic simulations revealed three-dimensional out-of-plane magnetic vortex states in stand-alone hemispherical granules and their arrays, and multi-domain patterns in large agglomerates and integrated films. Once the granules coalesce into small chains or clusters, the coercivity values increased due to the reduction of inter-granular spacing and strengthening of the magnetostatic interaction. Further growth leads to the formation of a continuous granulated film which strongly affected the coercivity and remanence. This was characterized by the domain wall nucleation and propagation leading to a stripe domain pattern. Magnetoresistance measurements as a function of external magnetic field are indicative of anisotropic magnetoresistance (AMR) for the continuous films electrodeposited on Si substrate. - Highlights: • Magnetic states of electrodeposited nickel in isolated spherical and agglomerated nanogranules, and a continuous film. • Preferential magnetization reversal mechanism in isolated granules is vortex state. • Micromagnetic simulations confirm the three-dimensional vortex. • Transition between the vortex state and multi-domain magnetic pattern causes a significant decrease in the coercive force. • Continuous nickel films electrodeposited on silicon substrate exhibit AMR whose magnitude increases with the film thickness

Electrodeposited zinc/nickel coatings. A review

Energy Technology Data Exchange (ETDEWEB)

Shoeib, Madiha A. [Central Metallurgical Research and Development Institute (CMRDI), Helwan, Cairo (Egypt). Surface Coating Dept.

2011-10-15

In recent years, the use of electrodeposited zinc-nickel coatings has significantly increased, mainly because of their superior corrosion resistance as compared with zinc. An additional strength of the process is that the proportion of the two metals, and thus the coating properties, can be varied. Initially, these alloy deposits were relatively brittle, with a tendency to crack-formation. More recently, ductile coatings have been developed. Now, as in the past, the emphasis has been on the cathodic corrosion protection which these coatings provide. Their properties can be further enhanced by post-treatment where additional developments have taken place. (orig.)

Controllable growth and magnetic properties of nickel nanoclusters electrodeposited on the ZnO nanorod template

International Nuclear Information System (INIS)

Tang Yang; Zhao Dongxu; Shen Dezhen; Zhang Jiying; Wang Xiaohua

2009-01-01

The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

Controllable growth and magnetic properties of nickel nanoclusters electrodeposited on the ZnO nanorod template

Energy Technology Data Exchange (ETDEWEB)

Tang Yang; Zhao Dongxu; Shen Dezhen; Zhang Jiying [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Wang Xiaohua, E-mail: dxzhao2000@yahoo.com.c [National Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 WeiXing Road, ChangChun 130022 (China)

2009-12-09

The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

Cathodic protection of steel by electrodeposited zinc-nickel alloy coatings

Energy Technology Data Exchange (ETDEWEB)

Baldwin, K.R.; Smith, C.J.E. [Defence Research Agency, Farnborough (United Kingdom). Structural Materials Centre; Robinson, M.J. [Cranfield Univ. (United Kingdom). School of Industrial and Manufacturing Science

1995-12-01

The ability of electrodeposited zinc-nickel alloy coatings to cathodically protect steel was studied in dilute chloride solutions. The potential distribution along steel strips partly electroplated with zinc-nickel alloys was determined, and the length of exposed steel that was held below the minimum protection potential (E{sub prot}) was taken as a measure of the level of cathodic protection (CP) provided by the alloy coatings. The level of CP afforded by zinc alloy coatings was found to decrease with increasing nickel content. When nickel content was increased to {approx} {ge} 21 wt%, no CP was obtained. Surface analysis of uncoupled zinc-nickel alloys that were immersed in sodium chloride (NaCl) solutions showed the concentration of zinc decreased in the surface layers while the concentration of nickel increased, indicating that the alloys were susceptible to dezincification. The analysis of zinc-nickel alloy coatings on partly electroplated steel strips that were immersed in chloride solution showed a significantly higher level of dezincification than that found for uncoupled alloy coatings. This effect accounted for the rapid loss of CP afforded to steel by some zinc alloy coatings, particularly those with high initial nickel levels.

A simple and efficient method of nickel electrodeposition for the cyclotron production of 64Cu

International Nuclear Information System (INIS)

Manrique-Arias, Juan C.; Avila-Rodriguez, Miguel A.

2014-01-01

Nickel targets for the cyclotron production of 64 Cu were prepared by electrodeposition on a gold backing from nickel chloride solutions using boric acid as buffer. Parameters studied were nickel chloride and boric acid concentration, temperature and current density. All plating conditions studied were successful obtaining efficiencies of approximately 90% in 2–3 h, reaching almost quantitative plating (>97%) in 10–20 h depending on the current density. All plated targets withstood proton irradiations up to 40 µA for 2 h. Recovered nickel was successfully recycled and reused with an overall efficiency >95%. - Highlights: • Simple and efficient method of Ni electrodeposition from NiCl 2 solutions. • Represents an improvement over current methods for the preparation of Ni targets. • All plated targets underwent irradiation and withstood currents up to 40 µA for 2 h. • Nickel target material was recycled and reused with an overall efficiency >95%. • Specific activity of 64 Cu was similar than that obtained with older methods of Ni plating

Characterization of nickel nanocones routed by electrodeposition without any template.

Science.gov (United States)

Hang, Tao; Li, Ming; Fei, Qin; Mao, Dali

2008-01-23

This work reports the synthesis of Ni nanocones by a one-step electrodeposition method without any template. With the addition of ethylenediamine dihydrochloride (EDA·2HCl) in the nickel plating solution, the novel Ni conical structure can be easily deposited onto different metal surfaces. The as-prepared nickel nanocones grow preferentially along [Formula: see text] directions with very sharp tips. The conical structures are single crystalline without any disruption of the lattice planes. In addition, the Ni nanocone structure is demonstrated to show magnetocrystalline anisotropy and enhance the magnetic properties when compared with other Ni nanostructures.

Electrodeposited Ni-B coatings: Formation and evaluation of hardness and wear resistance

International Nuclear Information System (INIS)

Krishnaveni, K.; Sankara Narayanan, T.S.N.; Seshadri, S.K.

2006-01-01

The formation of electrodeposited Ni-B alloy coatings using a dimethylamine borane (DMAB) modified Watt's nickel bath and evaluation of their structural characteristics, hardness and wear resistance are discussed. The boron content in the electrodeposited Ni-B alloy coating is determined by the ratio of rate of reduction of nickel and rate of decomposition of DMAB. The boron content of the electrodeposited Ni-B coating decreases as the current density increased from 0.4 to 4 A dm -2 . XRD diffraction pattern of electrodeposited Ni-B coatings in their as-plated condition exhibits the presence of Ni (1 1 1) (2 0 0) and (2 2 0) reflections with (1 1 1) texture. Heat treatment at 400 deg. C for 1 h has resulted in the formation of nickel boride phases, which results in an increase in hardness and wear resistance. The mechanism of wear in electrodeposited Ni-B coatings is intensive plastic deformation of the coating due to the ploughing action of the hard counter disk

Electrodeposition of nickel particles and their characterization

Energy Technology Data Exchange (ETDEWEB)

Martinez, G. T. [Centro de Investigacion en Quimica Aplicada, Laboratorio de Microscopia. Blvd. Enrique Reyna No. 140, Saltillo 25253, Coahuila (Mexico); Zavala, G.; Videa, M. [ITESM, Campus Monterrey, Depto. de Fisica, Av. Garza Sada 2501 Sur, Monterrey 64849, N. L. (Mexico)], e-mail: gtadeo@ciqa.mx

2009-07-01

Electrodeposition of nickel particles on ITO substrates is achieved by current pulse reduction. A comparison between potential pulse and current pulse experiments presents differences in particle size and particle size distribution. The latter shows smaller particle size dispersion than what is found with potential pulses. Characterization of the particles carried out by Atomic Force Microscopy shows particles with average sizes between 100 to 300 nm. Magnetic characterization by Magnetic Force Microscopy and SQUID shows that particles of {approx} 300 nm were ferromagnetic with a coercive field of 200 Oe and a saturation magnetization of 40 x 10{sup -6} emu at 300 K. (Author)

Experimental Study of Nonequilibrium Electrodeposition of Nanostructures on Copper and Nickel for Photochemical Fuel Cell Application

Directory of Open Access Journals (Sweden)

Rajesh K. Shanmugam

2011-01-01

Full Text Available To increase the performance of photochemical fuel cells, nonequilibrium electrodeposition has been performed on Cu and Ni to make photosensitive anodes. Processing parameters including electrolyte concentration, and electrode potential were studied using cyclic voltammetry. Scanning electron microscopy (SEM and X-ray Spectroscopy (EDS were performed to understand the formation of the nanostructures during the nonequilibrium deposition of copper fractals. An increase in the deposition rate was observed with the increase in electrolyte concentration (from 0.05 M to 1.0 M. Similar trend was found when the cathode potential was decreased from −0.5 V to −4.5 V. The effect of substrate material was also examined. Porous fractal structures on copper were achieved, while the deposited material showed high density of surface cracks on nickel. The fractal structures deposited on copper electrode with the increased surface area were converted into copper oxide by oxidation in air. Such oxide samples were made into anodes for photochemical fuel cell application. We demonstrated that an increase in the magnitude of open circuit output voltage is associated with the increase in the fractal surface area under the ultraviolet irradiation test conditions. However, the electrodeposited fractals on nickel showed very limited increase in the magnitude of open circuit voltage.

The effect of nickel electrodeposition on magnetic properties of CoFeSiB amorphous wire

International Nuclear Information System (INIS)

Atalay, F.E.

2004-01-01

Nickel films were electrodeposited on rapidly quenched amorphous wires from nitrate bath using a constant voltage. It was found that the pH of plating bath had a very strong effect on the formation of nickel films. The magnetic field, H, dependence of the impedance, of nickel plated (Co 0.94 Fe 0.06 ) 72.5 Si 12.5 B 15 wires have been investigated using a Hewlett-Packard 4294A impedance analyser with 42941A impedance probe. The best elecroplating condition and GMI response were obtained for the plated wire at pH 5 for 30 min plating time

Influence of current density on microstructure and properties of electrodeposited nickel-alumina composite coatings

International Nuclear Information System (INIS)

Góral, Anna; Nowak, Marek; Berent, Katarzyna; Kania, Bogusz

2014-01-01

Highlights: • Current density of the electrodeposition affects the incorporation of Al 2 O 3 in Ni matrix. • Ni/Al 2 O 3 composite coatings exhibit changes in crystallographic texture. • The pitting corrosion effects were observed in Ni/Al 2 O 3 coatings. • Residual stresses were decreased with increasing current density and coating thickness. - Abstract: Electrodeposition process is a very promising method for producing metal matrix composites reinforced with ceramic particles. In this method insoluble particles suspended in an electrolytic bath are embedded in a growing metal layer. This paper is focused on the investigations of the nickel matrix nanocomposite coatings with hard α-Al 2 O 3 nano-particles, electrochemically deposited from modified Watts-type baths on steel substrates. The influence of various current densities on the microstructure, residual stresses, texture, hardness and corrosion resistance of the deposited nickel/alumina coatings was investigated. The surface morphology, cross sections of the coatings and distribution of the ceramic particles in the metal matrix were examined by scanning electron microscopy. The phase composition, residual stresses and preferred grain orientation of the coatings were characterized using X-ray diffraction techniques. The coating morphology revealed that α-Al 2 O 3 particles show a distinct tendency to form agglomerates, approximately uniformly distributed into the nickel matrix

Super-hydrophobic nickel films with micro-nano hierarchical structure prepared by electrodeposition

International Nuclear Information System (INIS)

Hang Tao; Hu Anmin; Ling Huiqin; Li Ming; Mao Dali

2010-01-01

Super-hydrophobic nickel films were prepared by a simple and low cost electrodepositing method. The surface morphologies of the films characterized by scanning electronic microscope exhibit hierarchical structure with micro-nanocones array, which can be responsible for their super-hydrophobic characteristic (water contact angle over 150 o ) without chemical modification. The wettability of the film can be varied from super-hydrophobic (water contact angle 154 o ) to relatively hydrophilic (water contact angle 87 o ) by controlling the size of the micro-nanocones. The mechanism of the hydrophobic characteristic of nickel films with this unique structure was illustrated by several models. Such micro-nanostructure and its special wettability are expected to be applied in the practical industry.

Characterisation of electrodeposited polycrystalline uranium dioxide thin films on nickel foil for industrial applications

International Nuclear Information System (INIS)

Adamska, A.M.; Bright, E. Lawrence; Sutcliffe, J.; Liu, W.; Payton, O.D.; Picco, L.; Scott, T.B.

2015-01-01

Polycrystalline uranium dioxide thin films were grown on nickel substrates via aqueous electrodeposition of a precursor uranyl salt. The arising semiconducting uranium dioxide thin films exhibited a tower-like morphology, which may be suitable for future application in 3D solar cell applications. The thickness of the homogenous, tower-like films reached 350 nm. Longer deposition times led to the formation of thicker (up to 1.5 μm) and highly porous films. - Highlights: • Electrodeposition of polycrystalline UO_2 thin films • Tower-like morphology for 3D solar cell applications • Novel technique for separation of heavy elements from radioactive waste streams

Melt impregnation as a post processing treatment for performance enhancement in high capacity 3D microporous tin-copper-nickel intermetallic anode for Li-ion battery supported by electrodeposited nickel scaffold: A structural study

Science.gov (United States)

Sengupta, Srijan; Patra, Arghya; Mitra, Arijit; Jena, Sambedan; Das, Karabi; Majumder, Subhasish Basu; Das, Siddhartha

2018-05-01

This paper communicates stabilization of a Sn anode by impregnating it within the porous framework of a Ni-scaffold. The impregnation is carried out by electrodeposition Sn on Ni-foam followed by heating at 300 °C for 1 h. The Ni-foam was also electrodeposited on a Cu foil prior to deposition of Sn. The melting step leads to the formation of Nisbnd Sn and Cusbnd Sn intermetallics within pores of the Ni-scaffold. Snsbnd Cu/Ni intermetallics lithiate following the active-inactive strategy in which the inactive Cu/Ni buffers the volume expansion while Sn lithiates. Furthermore, this entire process takes place within Ni-scaffold which resists material pulverization and delamination and provide better electronic pathway for charge transfer. This active-inactive Sn:Snsbnd Cu/Ni intermetallic within a protected Ni-scaffold assembly results in 100th cycle discharge capacity of 587.9 mA h/g at a rate of 500 mA/g (0.5 C), and superior rate capability delivering 463 mAh/g at a rate of 2 A/g (2 C) while retaining structural integrity as compared to pure Sn electrodeposited (without heat-treatment) on the nickel scaffold.

Lithographically patterned electrodeposition of gold, silver, and nickel nanoring arrays with widely tunable near-infrared plasmonic resonances.

Science.gov (United States)

Halpern, Aaron R; Corn, Robert M

2013-02-26

A novel low-cost nanoring array fabrication method that combines the process of lithographically patterned nanoscale electrodeposition (LPNE) with colloidal lithography is described. Nanoring array fabrication was accomplished in three steps: (i) a thin (70 nm) sacrificial nickel or silver film was first vapor-deposited onto a plasma-etched packed colloidal monolayer; (ii) the polymer colloids were removed from the surface, a thin film of positive photoresist was applied, and a backside exposure of the photoresist was used to create a nanohole electrode array; (iii) this array of nanoscale cylindrical electrodes was then used for the electrodeposition of gold, silver, or nickel nanorings. Removal of the photoresist and sacrificial metal film yielded a nanoring array in which all of the nanoring dimensions were set independently: the inter-ring spacing was fixed by the colloidal radius, the radius of the nanorings was controlled by the plasma etching process, and the width of the nanorings was controlled by the electrodeposition process. A combination of scanning electron microscopy (SEM) measurements and Fourier transform near-infrared (FT-NIR) absorption spectroscopy were used to characterize the nanoring arrays. Nanoring arrays with radii from 200 to 400 nm exhibited a single strong NIR plasmonic resonance with an absorption maximum wavelength that varied linearly from 1.25 to 3.33 μm as predicted by a simple standing wave model linear antenna theory. This simple yet versatile nanoring array fabrication method was also used to electrodeposit concentric double gold nanoring arrays that exhibited multiple NIR plasmonic resonances.

Effects of deposition temperature on electrodeposition of zinc–nickel alloy coatings

International Nuclear Information System (INIS)

Qiao, Xiaoping; Li, Helin; Zhao, Wenzhen; Li, Dejun

2013-01-01

Highlights: ► Both normal and anomalous deposition can be realized by changing bath temperature. ► The Ni content in Zn–Ni alloy deposit increases sharply as temperature reach 60 °C. ► The abrupt change in coating composition is caused by the shift of cathodic potential. ► The deposition temperature has great effect on microstructure of Zn–Ni alloy deposit. -- Abstract: Zinc–nickel alloy coatings were electrodeposited on carbon steel substrates from the ammonium chloride bath at different temperatures. The composition, phase structure and morphology of these coatings were analyzed by energy dispersive spectrometer, X-ray diffractometer and scanning electron microscopy respectively. Chronopotentiometry and potentiostatic methods were also employed to analyze the possible causes of the composition and structure changes induced by deposition temperature. It has been shown that both normal and anomalous co-deposition of zinc and nickel could be realized by changing deposition temperature under galvanostatic conditions. The abrupt changes in the composition and phase structure of the zinc–nickel alloy coatings were observed when deposition temperature reached 60 °C. The sharply decrease of current efficiency for zinc–nickel co-deposition was also observed when deposition temperature is higher than 40 °C. Analysis of the partial current densities showed that the decrease of current efficiency with the rise of deposition temperature was due to the enhancement of the hydrogen evolution. It was also confirmed that the ennoblement of cathodic potential was the cause for the increase of nickel content in zinc–nickel alloy coatings as a result of deposition temperature rise. The good zinc–nickel alloy coatings with compact morphology and single γ phase could be obtained when the deposition temperature was fixed at 30–40 °C

Challenges of sample preparation for cross sectional EBSD analysis of electrodeposited nickel films

DEFF Research Database (Denmark)

Alimadadi, Hossein; Pantleon, Karen

2009-01-01

Thorough microstructure and crystallographic orientation analysis of thin films by means of electron backscatter diffraction requires cross section preparation of the film-substrate compound. During careful preparation, changes of the rather non-stable as-deposited microstructure must be avoided....... Different procedures for sample preparation including mechanical grinding and polishing, electropolishing and focused ion beam milling have been applied to a nickel film electrodeposited on top of an amorphous Ni-P layer on a Cu-substrate. Reliable EBSD analysis of the whole cross section can be obtained...

Controlling electrodeposited ultrathin amorphous Fe hydroxides film on V-doped nickel sulfide nanowires as efficient electrocatalyst for water oxidation

Science.gov (United States)

Shang, Xiao; Yan, Kai-Li; Lu, Shan-Shan; Dong, Bin; Gao, Wen-Kun; Chi, Jing-Qi; Liu, Zi-Zhang; Chai, Yong-Ming; Liu, Chen-Guang

2017-09-01

Developing cost-effective electrocatalysts with both high activity and stability remains challenging for oxygen evolution reaction (OER) in water electrolysis. Herein, based on V-doped nickel sulfide nanowire on nickel foam (NiVS/NF), we further conduct controllable electrodeposition of Fe hydroxides film on NiVS/NF (eFe/NiVS/NF) to further improve OER performance and stability. For comparison, ultrafast chemical deposition of Fe hydroxides on NiVS/NF (uFe/NiVS/NF) is also utilized. V-doping of NiVS/NF may introduce more active sites for OER, and nanowire structure can expose abundant active sites and facilitate mass transport. Both of the two depositions generate amorphous Fe hydroxides film covering on the surface of nanowires and lead to enhanced OER activities. Furthermore, electrodeposition strategy realizes uniform Fe hydroxides film on eFe/NiVS/NF confirmed by superior OER activity of eFe/NiVS/NF than uFe/NiVS/NF with relatively enhanced stability. The OER activity of eFe/NiVS/NF depends on various electrodepositon time, and the optimal time (15 s) is obtained with maximum OER activity. Therefore, the controllable electrodeposition of Fe may provide an efficient and simple strategy to enhance the OER properties of electrocatalysts.

Microstructure and surface mechanical properties of pulse electrodeposited nickel

Energy Technology Data Exchange (ETDEWEB)

Ul-Hamid, A., E-mail: anwar@kfupm.edu.sa [Center of Research Excellence in Corrosion (CoRE-C), Research Institute, King Fahd University of Petroleum and Minerals, P.O. Box 1073, Dhahran 31261 (Saudi Arabia); Dafalla, H.; Quddus, A.; Saricimen, H.; Al-Hadhrami, L.M. [Center of Research Excellence in Corrosion (CoRE-C), Research Institute, King Fahd University of Petroleum and Minerals, P.O. Box 1073, Dhahran 31261 (Saudi Arabia)

2011-09-01

The surface of carbon steel was modified by electrochemical deposition of Ni in a standard Watt's bath using dc and pulse plating electrodeposition. The aim was to compare the microstructure and surface mechanical properties of the deposit obtained by both techniques. Materials characterization was conducted using field emission scanning electron microscope fitted with scanning transmission electron detector, atomic force microscope and X-ray diffractometer. Nanoindentation hardness, elastic modulus, adhesion, coefficients of friction and wear rates were determined for both dc and pulse electrodeposits. Experimental results indicate that pulse electrodeposition produced finer Ni grains compared to dc plating. Size of Ni grains increased with deposition. Both dc and pulse deposition resulted in grain growth in preferred (2 0 0) orientation. However, presence of Ni (1 1 1) grains increased in deposits produced by pulse deposition. Pulse plated Ni exhibited higher hardness, creep and coefficient of friction and lower modulus of elasticity compared to dc plated Ni.

THE LOCAL LASER-STIMULATED ELECTRODEPOSITION OF THE NICKEL

Directory of Open Access Journals (Sweden)

V. A. Zabludovskyi

2009-12-01

Full Text Available The mask-free method for obtaining the local nickel coatings using laser radiation is developed. The parameters of local nickel coatings are calculated. The rate of electroplating process is estimated.

Electrodeposited nickel oxide and graphene modified carbon ionic liquid electrode for electrochemical myglobin biosensor

International Nuclear Information System (INIS)

Sun, Wei; Gong, Shixing; Deng, Ying; Li, Tongtong; Cheng, Yong; Wang, Wencheng; Wang, Lei

2014-01-01

By using ionic liquid 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE) as the substrate electrode, graphene (GR) and nickel oxide (NiO) were in situ electrodeposited step by step to get a NiO/GR nanocomposite modified CILE. Myoglobin (Mb) was further immobilized on the surface of NiO/GR/CILE with a Nafion film to get the electrochemical sensor denoted as Nafion/Mb/NiO/GR/CILE. Cyclic voltammetric experiments indicated that a pair of well-defined quasi-reversible redox peaks appeared in pH 3.0 phosphate buffer solution with the formal peak potential (E 0′ ) located at − 0.188 V (vs. SCE), which was the typical characteristics of Mb Fe(III)/Fe(II) redox couples. So the direct electron transfer of Mb was realized and promoted due to the presence of the NiO/GR nanocomposite on the electrode. Based on the cyclic voltammetric data, the electrochemical parameters of Mb on the modified electrode were calculated. The Mb modified electrode showed an excellent electrocatalytic activity towards the reduction of different substrates including trichloroacetic acid and H 2 O 2 . Therefore a third-generation electrochemical Mb biosensor based on NiO/GR/CILE was constructed with good stability and reproducibility. - Highlights: • Graphene and nickel oxide nanocomposites were prepared by electrodeposition. • Electrochemical myoglobin sensor was prepared on a nanocomposite modified electrode. • Direct electrochemistry and electrocatalysis of myglobin were realized

Texture and microstructure evolution in nickel electrodeposited from an additive-free Watts electrolyte

DEFF Research Database (Denmark)

Alimadadi, Hossein; da Silva Fanta, Alice Bastos; Kasama, Takeshi

2016-01-01

Nickel layers with 〈100〉, 〈210〉, 〈110〉 and 〈211〉 fiber textures were electrodeposited from additive-free Watts type electrolytes by adjusting both the pH and the applied current density. Quantitative crystallographic texture analysis by XRD was supplemented by micro-texture analysis applying EBSD....... While XRD results correspond to absorption-weighted averages over the top part of the layer, EBSD on the cross section allowed studying the texture evolution as a function of distance to the substrate. Although layer growth started on amorphous substrates, implying that nucleation occurs unbiased...

One-step electrodeposited nickel cobalt sulfide nanosheet arrays for high-performance asymmetric supercapacitors.

Science.gov (United States)

Chen, Wei; Xia, Chuan; Alshareef, Husam N

2014-09-23

A facile one-step electrodeposition method is developed to prepare ternary nickel cobalt sulfide interconnected nanosheet arrays on conductive carbon substrates as electrodes for supercapacitors, resulting in exceptional energy storage performance. Taking advantages of the highly conductive, mesoporous nature of the nanosheets and open framework of the three-dimensional nanoarchitectures, the ternary sulfide electrodes exhibit high specific capacitance (1418 F g(-1) at 5 A g(-1) and 1285 F g(-1) at 100 A g(-1)) with excellent rate capability. An asymmetric supercapacitor fabricated by the ternary sulfide nanosheet arrays as positive electrode and porous graphene film as negative electrode demonstrates outstanding electrochemical performance for practical energy storage applications. Our asymmetric supercapacitors show a high energy density of 60 Wh kg(-1) at a power density of 1.8 kW kg(-1). Even when charging the cell within 4.5 s, the energy density is still as high as 33 Wh kg(-1) at an outstanding power density of 28.8 kW kg(-1) with robust long-term cycling stability up to 50,000 cycles.

One-Step Electrodeposited Nickel Cobalt Sulfide Nanosheet Arrays for High-Performance Asymmetric Supercapacitors

KAUST Repository

Chen, Wei

2014-09-23

A facile one-step electrodeposition method is developed to prepare ternary nickel cobalt sulfide interconnected nanosheet arrays on conductive carbon substrates as electrodes for supercapacitors, resulting in exceptional energy storage performance. Taking advantages of the highly conductive, mesoporous nature of the nanosheets and open framework of the three-dimensional nanoarchitectures, the ternary sulfide electrodes exhibit high specific capacitance (1418 F g(-1) at 5 A g(-1) and 1285 F g(-1) at 100 A g(-1)) with excellent rate capability. An asymmetric supercapacitor fabricated by the ternary sulfide nanosheet arrays as positive electrode and porous graphene film as negative electrode demonstrates outstanding electrochemical performance for practical energy storage applications. Our asymmetric supercapacitors show a high energy density of 60 Wh kg(-1) at a power density of 1.8 kW kg(-1). Even when charging the cell within 4.5 s, the energy density is still as high as 33 Wh kg(-1) at an outstanding power density of 28.8 kW kg(-1) with robust long-term cycling stability up to 50 000 cycles.

One-Step Electrodeposited Nickel Cobalt Sulfide Nanosheet Arrays for High-Performance Asymmetric Supercapacitors

KAUST Repository

Chen, Wei; Xia, Chuan; Alshareef, Husam N.

2014-01-01

A facile one-step electrodeposition method is developed to prepare ternary nickel cobalt sulfide interconnected nanosheet arrays on conductive carbon substrates as electrodes for supercapacitors, resulting in exceptional energy storage performance. Taking advantages of the highly conductive, mesoporous nature of the nanosheets and open framework of the three-dimensional nanoarchitectures, the ternary sulfide electrodes exhibit high specific capacitance (1418 F g(-1) at 5 A g(-1) and 1285 F g(-1) at 100 A g(-1)) with excellent rate capability. An asymmetric supercapacitor fabricated by the ternary sulfide nanosheet arrays as positive electrode and porous graphene film as negative electrode demonstrates outstanding electrochemical performance for practical energy storage applications. Our asymmetric supercapacitors show a high energy density of 60 Wh kg(-1) at a power density of 1.8 kW kg(-1). Even when charging the cell within 4.5 s, the energy density is still as high as 33 Wh kg(-1) at an outstanding power density of 28.8 kW kg(-1) with robust long-term cycling stability up to 50 000 cycles.

Nanoindentation and micro-mechanical fracture toughness of electrodeposited nanocrystalline Ni-W alloy films

Energy Technology Data Exchange (ETDEWEB)

Armstrong, D.E.J., E-mail: david.armstrong@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Haseeb, A.S.M.A. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Roberts, S.G.; Wilkinson, A.J. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Bade, K. [Institut fuer Mikrostrukturtechnik (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2012-04-30

Nanocrystalline nickel-tungsten alloys have great potential in the fabrication of components for microelectromechanical systems. Here the fracture toughness of Ni-12.7 at.%W alloy micro-cantilever beams was investigated. Micro-cantilevers were fabricated by UV lithography and electrodeposition and notched by focused ion beam machining. Load was applied using a nanoindenter and fracture toughness was calculated from the fracture load. Fracture toughness of the Ni-12.7 at.%W was in the range of 1.49-5.14 MPa {radical}m. This is higher than the fracture toughness of Si (another important microelectromechanical systems material), but considerably lower than that of electrodeposited nickel and other nickel based alloys. - Highlights: Black-Right-Pointing-Pointer Micro-scale cantilevers manufactured by electro-deposition and focused ion beam machining. Black-Right-Pointing-Pointer Nanoindenter used to perform micro-scale fracture test on Ni-13at%W micro-cantilevers. Black-Right-Pointing-Pointer Calculation of fracture toughness of electrodeposited Ni-13at%W thin films. Black-Right-Pointing-Pointer Fracture toughness values lower than that of nanocrystalline nickel.

Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

Science.gov (United States)

Pandey, B.; Das, D.; Kar, A. K.

2015-05-01

Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current-voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp2 content in DLC matrix. The magnetic moment vs. magnetic field (m-H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

Nickel coating electroplated characterization with and without carbon nanotubes

International Nuclear Information System (INIS)

Lopes, A.C.; Banczek, E.P.; Cunha, M.T.; Rodrigues, P.R.P.; Terada, M.

2010-01-01

The metals have great application, but when their properties are not suitable they should be improved through treatments to increase corrosion resistance, mechanical and wear. The metals electrodeposition such as nickel is one of treatment options. This study aims the development a nickel coating with and without (CNT), obtained by electrodeposition on aluminum alloy AA6061. The nickel electrodeposition was performed with cyclic voltammetry and chronoamperometry. Open circuit potential and anodic polarization curves were carried out samples characterization. The microstructure and the chemical composition of the M x O z coating were studied using the scanning electron microscopy, energy dispersion spectroscopy and X-ray diffraction. The results indicated that the nickel coating improve the corrosion resistance of aluminum in the presence of CNT. (author)

Acidic aqueous uranium electrodeposition for target fabrication

International Nuclear Information System (INIS)

Saliba-Silva, A.M.; Oliveira, E.T.; Garcia, R.H.L.; Durazzo, M.

2013-01-01

Direct irradiation of targets inside nuclear research or multiple purpose reactors is a common route to produce 99 Mo- 99m Tc radioisotopes. The electroplating of low enriched uranium over nickel substrate might be a potential alternative to produce targets of 235 U. The electrochemistry of uranium at low temperature might be beneficial for an alternative route to produce 99 Mo irradiation LEU targets. Electrodeposition of uranium can be made using ionic and aqueous solutions producing uranium oxide deposits. The performance of uranium electrodeposition is relatively low because a big competition with H 2 evolution happens inside the window of electrochemical reduction potential. This work explores possibilities of electroplating uranium as UO 2 2+ (Uranium-VI) in order to achieve electroplating uranium in a sufficient amount to be commercially irradiated in the future Brazilian RMB reactor. Electroplated nickel substrate was followed by cathodic current electrodeposition from aqueous UO 2 (NO 3 ) 2 solution. EIS tests and modeling showed that a film formed differently in the three tested cathodic potentials. At the lower level, (-1.8V) there was an indication of a double film formation, one overlaying the other with ionic mass diffusion impaired at the interface with nickel substrate as showed by the relatively lower admittance of Warburg component. (author)

Characterizations of electrodeposited Ni–CeO{sub 2} nanocomposite coatings

Energy Technology Data Exchange (ETDEWEB)

Kasturibai, S., E-mail: s.kasturibai@yahoo.co.in [Department of Chemistry, Alagappa Government Arts College, Karaikudi 630 003, Tamilnadu (India); Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamilnadu (India); Kalaignan, G. Paruthimal, E-mail: pkalaignan@yahoo.com [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, School of Chemical Sciences, Alagappa University, Karaikudi 630 003, Tamilnadu (India)

2014-10-15

The expansion of current machinery requires metallic materials with better surface properties. In the present investigation, CeO{sub 2} reinforced nickel nanocomposite coatings were deposited on mild steel substrate by direct current electrodeposition process employing nickel acetate bath. The effect of incorporation of CeO{sub 2} particles in the Ni nanocomposite coatings on the micro hardness and corrosion behaviour has been evaluated. Smooth and compact nanocomposite deposits containing well-distributed cerium oxide particles were obtained. The crystallite structure was fcc for electrodeposited nickel and Ni–CeO{sub 2} nanocomposite coatings. It has been observed that, the presence of CeO{sub 2} nanoparticles favours the [111] and [200] texture of nickel matrix. The co-deposition of CeO{sub 2} nanoparticles with nickel was found to be favoured at applied current density of 8 A dm{sup −2}. The micro hardness values of the nickel nanocomposite coatings (725 HV) was higher than that of pure nickel (265 HV).The decrease in I{sub corr} values and increase in Constant Phase Element values were investigated in 3.5% NaCl solution which showed the higher corrosion resistant nature of Ni–CeO{sub 2} coatings. - Highlights: • Ni–CeO{sub 2} composite coatings have electrodeposited from eco-friendly acetate bath. • Inclusion of CeO{sub 2} in the composite coating has refined the crystallite size. • Micro hardness values have increased with CeO{sub 2} content in the composite coatings. • The negative shift of E{sub corr} confirming cathodic protective nature of coatings.

Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

Energy Technology Data Exchange (ETDEWEB)

Pandey, B., E-mail: pandey.beauty@yahoo.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Das, D. [UGC-DAE CSR, Sector III/LB-8, Bidhan Nagar, Kolkata 700098 (India); Kar, A.K. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

2015-05-15

Highlights: • Electrical and magnetic properties of DLC and Ni-DLC thin films are studied. • The ohmicity and conductivity of DLC films rise with nickel addition. • The ohmicity of Ni-DLC is enhanced with increase in dilution of electrolyte. • Dielectric loss is high for Ni-DLC and decreases with frequency till 100 kHz. • (m–H) and (m–T) curves of Ni-DLC indicate superparamagnetic behavior. - Abstract: Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current–voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp{sup 2} content in DLC matrix. The magnetic moment vs. magnetic field (m–H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

Effect of natural and magnetic convections on the structure of electrodeposited zinc-nickel alloy

Energy Technology Data Exchange (ETDEWEB)

Levesque, A., E-mail: alexandra.levesque@univ-reims.fr [LACMDTI URCA, BP 1039, 51687 Reims Cedex2 (France); Chouchane, S. [Faculte des Sciences, Universite Badji Mokhtar, Annaba (Algeria); Douglade, J. [LACMDTI URCA, BP 1039, 51687 Reims Cedex2 (France); Rehamnia, R. [Faculte des Sciences, Universite Badji Mokhtar, Annaba (Algeria); Chopart, J.-P. [LACMDTI URCA, BP 1039, 51687 Reims Cedex2 (France)

2009-06-30

The effects of a magnetic field applied in a direction parallel or perpendicular to the cathode substrate plane, during electrodeposition process of Zn-Ni alloy have been investigated by means of chronoamperometric measurements, X-ray diffraction and EDX analysis. The modification of crystal orientation of the alloy by the superimposition of a high magnetic field is discussed for alloys with a content of nickel range 6-13 at%. Whatever the phase composition obtained without magnetic field, either {gamma}-Ni{sub 5}Zn{sub 21} or a mixture of the {gamma} and zinc phases, which depends on the concentration of Ni{sup 2+} in the electrolyte bath, the preferential orientation (1 0 1) of the zinc phase is always favoured with perpendicular and parallel magnetic field. There is no saturation of this effect with amplitude of B up to 8 T. A study of different geometric configurations of the cathode, which induce more or less natural convection, consolidates these results. The structural modifications of Zn-Ni alloy electrodeposits are thus probably due to a magnetohydrodynamic effect. An additional phenomenon is observed in presence of a perpendicular applied magnetic field since the (3 3 0) preferential orientation of the {gamma}-Ni{sub 5}Zn{sub 21} disappears with high values of B.

Effect of natural and magnetic convections on the structure of electrodeposited zinc-nickel alloy

International Nuclear Information System (INIS)

Levesque, A.; Chouchane, S.; Douglade, J.; Rehamnia, R.; Chopart, J.-P.

2009-01-01

The effects of a magnetic field applied in a direction parallel or perpendicular to the cathode substrate plane, during electrodeposition process of Zn-Ni alloy have been investigated by means of chronoamperometric measurements, X-ray diffraction and EDX analysis. The modification of crystal orientation of the alloy by the superimposition of a high magnetic field is discussed for alloys with a content of nickel range 6-13 at%. Whatever the phase composition obtained without magnetic field, either γ-Ni 5 Zn 21 or a mixture of the γ and zinc phases, which depends on the concentration of Ni 2+ in the electrolyte bath, the preferential orientation (1 0 1) of the zinc phase is always favoured with perpendicular and parallel magnetic field. There is no saturation of this effect with amplitude of B up to 8 T. A study of different geometric configurations of the cathode, which induce more or less natural convection, consolidates these results. The structural modifications of Zn-Ni alloy electrodeposits are thus probably due to a magnetohydrodynamic effect. An additional phenomenon is observed in presence of a perpendicular applied magnetic field since the (3 3 0) preferential orientation of the γ-Ni 5 Zn 21 disappears with high values of B.

Nanoindentation and micro-mechanical fracture toughness of electrodeposited nanocrystalline Ni–W alloy films

International Nuclear Information System (INIS)

Armstrong, D.E.J.; Haseeb, A.S.M.A.; Roberts, S.G.; Wilkinson, A.J.; Bade, K.

2012-01-01

Nanocrystalline nickel–tungsten alloys have great potential in the fabrication of components for microelectromechanical systems. Here the fracture toughness of Ni–12.7 at.%W alloy micro-cantilever beams was investigated. Micro-cantilevers were fabricated by UV lithography and electrodeposition and notched by focused ion beam machining. Load was applied using a nanoindenter and fracture toughness was calculated from the fracture load. Fracture toughness of the Ni–12.7 at.%W was in the range of 1.49–5.14 MPa √m. This is higher than the fracture toughness of Si (another important microelectromechanical systems material), but considerably lower than that of electrodeposited nickel and other nickel based alloys. - Highlights: ► Micro-scale cantilevers manufactured by electro-deposition and focused ion beam machining. ► Nanoindenter used to perform micro-scale fracture test on Ni-13at%W micro-cantilevers. ► Calculation of fracture toughness of electrodeposited Ni-13at%W thin films. ► Fracture toughness values lower than that of nanocrystalline nickel.

Electrodeposition of engineering alloy coatings

DEFF Research Database (Denmark)

Christoffersen, Lasse

Nickel based electrodeposited alloys were investigated with respect to their deposition process, heat treatment, hardness, corrosion resistance and combined wear-corrosion resistance. The investigated alloys were Ni-B, Ni-P and Ni-W, which are not fully developed for industrial utilisation...... are written in brackets). Temperature and especially pH influenced the cathodic efficiency of the electrodeposition processes for Ni-W and Ni-P. Mass balance problems of the development alloy processes are identified.Heat treatment for one hour at approx. 350°C, 400°C and 600°C of electrodeposited Ni-B, Ni......-P and Ni-W, respectively, resulted in hardness values of approx. 1000 HV0.1 in the case of Ni-P(6), approx. 1100 HV0.1 in the case of Ni-W(40-53) and approx. 1300 HV0.1 in the case of Ni-B(5). Cracks, which emerged during electrodeposition and heat treatment, were observed on Ni-W and Ni-B.The corrosion...

Effect of parameters on the electrodeposition of Ni-TiO2 nanocomposite coatings

International Nuclear Information System (INIS)

Le Thi Phuong Thao; Nguyen Duc Hung; Nguyen Duy Ket

2013-01-01

The Ni-TiO 2 composite was formed from nickel chloride solution by coelectrodeposition. Effect of stirring rate, current density, kind of current, electrodeposition time and concentration of TiO 2 in the solution on the codeposition of the particle in the nanocomposite coating was investigated. The composition of coating was characterized with energy dispersive analyzer system (EDX). Results showed that, the amount of nano-TiO 2 embedded in coatings depended on these factors. When the amount of nanoparticles in bath of electrochemical was 6 g/1, the codeposition of the TiO 2 particle in the matrix reached 10.53% at current density 3 A/dm 2 , stirring rate of 600 rpm and 20 minutes electrodeposition. (author)

Interpretation of microstructure evolution during self-annealing and thermal annealing of nanocrystalline electrodeposits-A comparative study

International Nuclear Information System (INIS)

Pantleon, Karen; Somers, Marcel A.J.

2010-01-01

Electrodeposition results in a non-equilibrium state of the as-deposited nanocrystalline microstructure, which evolves towards an energetically more favorable state as a function of time and/or temperature upon deposition. Real-time investigation of the evolving microstructure in copper, silver and nickel electrodeposits was achieved by time-resolved X-ray diffraction line profile analysis and crystallographic texture analysis during room temperature storage and during isothermal annealing at elevated temperatures. These in-situ studies with unique time resolution allowed quantification of the self-annealing kinetics of copper and silver electrodeposits as well as the annealing kinetics of electrodeposited nickel. Similarities and characteristic differences of the kinetics and mechanisms of microstructure evolution in the various electrodeposits are discussed and the experimental results are attempted to be interpreted in terms of recovery, recrystallization and grain growth.

AN ELECTROPLATING METHOD OF FORMING PLATINGS OF NICKEL, COBALT, NICKEL ALLOYS OR COBALT ALLOYS

DEFF Research Database (Denmark)

1997-01-01

An electroplating method of forming platings of nickel, cobalt, nickel alloys or cobalt alloys with reduced stresses in an electrodepositing bath of the type: Watt's bath, chloride bath or a combination thereof, by employing pulse plating with periodic reverse pulse and a sulfonated naphthalene...

THE EFFECT OF IRON ION TO THE REMOVAL OF NICKEL ION FROM ELECTROPLATING WASTEWATER USING DOUBLE CHAMBER ELECTRODEPOSITION CELL (DCEC REACTOR

Directory of Open Access Journals (Sweden)

Djaenudin Djaenudin

2017-05-01

Full Text Available Modern society demands industrial technology advances to produce products that have high durability and long utilization lives. Materials made from ferrous metal become a solution to meet these industry needs. Ferrous metal is corrosive and it requires more care to support the performance. Electroplating or metal coating applied to iron or nickel solves this problem. In the production process, the usage of nickel is only 30%-40% and the remaining 60-70% is wasted through effluent. Nickel is a toxic heavy metal that can cause cancer. The purpose of this study is to evaluate the effect of iron concentration on nickel metal removal in electroplating wastewater using an insulated electrolytic reactor double chamber electrodeposition cell (DCEC. The result of this study shows that any ratio variation of iron concentration to nickel gives varying impacts on nickel removal efficiency, electric current efficiency, and specific energy. On the fourth variation, the iron ratio of 1.29% removed 83.1% nickel (the highest removal efficiency at the cost of 20.687 kWh / kg specific energy. The number is extremely high for energy needs. On the other hand, the variation of iron ratio of 1.73% consumpting only 15.067 kWh / kg, the lowest specific energy needs, resulted in the lowest removal efficiency of 63.6%.

Bright metal coatings from sustainable electrolytes: the effect of molecular additives on electrodeposition of nickel from a deep eutectic solvent.

Science.gov (United States)

Abbott, Andrew P; Ballantyne, Andrew; Harris, Robert C; Juma, Jamil A; Ryder, Karl S

2017-01-25

Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the [111] orientation whereas DMH and BA direct crystal growth to the [220] orientation.

Electrochemically deposited hybrid nickel-cobalt hexacyanoferrate nanostructures for electrochemical supercapacitors

International Nuclear Information System (INIS)

Safavi, A.; Kazemi, S.H.; Kazemi, H.

2011-01-01

Highlights: → Nanostructured hybrid nickel-cobalt hexacyanoferrate is used in supercapacitors. → A high capacitance (765 F g -1 ) is obtained at a specific current of 0.2 A g -1 . → Long cycle-life and excellent stability are demonstrated during 1000 cycles. - Abstract: This study describes the use of electrodeposited nanostructured hybrid nickel-cobalt hexacyanoferrate in electrochemical supercapacitors. Herein, various compositions of nickel and cobalt hexacyanoferrates (Ni/CoHCNFe) nanostructures are electrodeposited on an inexpensive stainless steel substrate using cyclic voltammetric (CV) method. The morphology of the electrodeposited nanostructures is studied using scanning electron microscopy, while their electrochemical characterizations are investigated using CV, galvanostatic charge and discharge and electrochemical impedance spectroscopy. The results show that the nanostructures of hybrid metal cyanoferrate, shows a much higher capacitance (765 F g -1 ) than those obtained with just nickel hexacyanoferrate (379 F g -1 ) or cobalt hexacyanoferrate (277 F g -1 ). Electrochemical impedance spectroscopy results confirm the favorable capacitive behavior of the electrodeposited materials. The columbic efficiency is approximately 95% based on the charge and discharge experiments. Long cycle-life and excellent stability of the nanostructured materials are also demonstrated during 1000 cycles.

Electrochemically deposited hybrid nickel-cobalt hexacyanoferrate nanostructures for electrochemical supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Safavi, A., E-mail: safavi@chem.susc.ac.ir [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Nanotechnology Research Institute, Shiraz University, Shiraz (Iran, Islamic Republic of); Kazemi, S.H., E-mail: habibkazemi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kazemi, H. [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

2011-10-30

Highlights: > Nanostructured hybrid nickel-cobalt hexacyanoferrate is used in supercapacitors. > A high capacitance (765 F g{sup -1}) is obtained at a specific current of 0.2 A g{sup -1}. > Long cycle-life and excellent stability are demonstrated during 1000 cycles. - Abstract: This study describes the use of electrodeposited nanostructured hybrid nickel-cobalt hexacyanoferrate in electrochemical supercapacitors. Herein, various compositions of nickel and cobalt hexacyanoferrates (Ni/CoHCNFe) nanostructures are electrodeposited on an inexpensive stainless steel substrate using cyclic voltammetric (CV) method. The morphology of the electrodeposited nanostructures is studied using scanning electron microscopy, while their electrochemical characterizations are investigated using CV, galvanostatic charge and discharge and electrochemical impedance spectroscopy. The results show that the nanostructures of hybrid metal cyanoferrate, shows a much higher capacitance (765 F g{sup -1}) than those obtained with just nickel hexacyanoferrate (379 F g{sup -1}) or cobalt hexacyanoferrate (277 F g{sup -1}). Electrochemical impedance spectroscopy results confirm the favorable capacitive behavior of the electrodeposited materials. The columbic efficiency is approximately 95% based on the charge and discharge experiments. Long cycle-life and excellent stability of the nanostructured materials are also demonstrated during 1000 cycles.

Characterization of zinc–nickel alloy electrodeposits obtained from ...

Indian Academy of Sciences (India)

Zinc alloy offers superior sacrificial protection to steel as the alloy dissolves more slowly than pure zinc. The degree of protection and the rate of dissolution depend on the alloying metal and its composition. Zinc-nickel alloy may also serve as at less toxic substitute for cadmium. In this paper the physico-chemical ...

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

International Nuclear Information System (INIS)

Jinlong, Lv; Tongxiang, Liang; Chen, Wang

2016-01-01

Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H_2SO_4 solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H_2SO_4 solution at room temperature. A large number of gaps between ‘cauliflower’ like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

Energy Technology Data Exchange (ETDEWEB)

Jinlong, Lv, E-mail: ljlbuaa@126.com [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Tongxiang, Liang; Chen, Wang [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China)

2016-03-15

Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H{sub 2}SO{sub 4} solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H{sub 2}SO{sub 4} solution at room temperature. A large number of gaps between ‘cauliflower’ like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol

International Nuclear Information System (INIS)

Liu, Yong; Liu, Lan; Shan, Jun; Zhang, Jingdong

2015-01-01

Highlights: • Pd and reduced graphene oxide are deposited on foam-Ni via electrodeposition. • Pd particles supported on RGO possess large active surface area. • Pd/RGO/foam-Ni shows high electrocatalytic activity for dechlorination of 4-CP. • 100% 4-CP can be removed on Pd/RGO/foam-Ni under optimum ECH conditions. - Abstract: A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na 2 SO 4 concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96 kJ mol −1 . Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP

High Discharge Rate Electrodeposited Zinc Electrode for Use in Alkaline Microbattery

Directory of Open Access Journals (Sweden)

A. L. Nor Hairin

2012-01-01

Full Text Available High discharge rate zinc electrode is prepared from electrodeposition process. The electrolytic bath consists of zinc chloride as the metal source and ammonium chloride as the supporting electrolyte. The concentration of the supporting electrolyte is varied from zero until 4 M, while the concentration of zinc chloride is fixed at 2 M. The aim is to produce a porous zinc coating with an enhanced and intimate interfacial area per unit volume. These characteristics shall contribute towards reduced ohmic losses, improved active material utilization, and subsequently producing high rate capacity electrochemical cell. Nitrogen physisorption at 77 K is used to measure the BET surface area and pore volume density of the zinc electrodeposits. The electrodeposited zinc electrodes are then fabricated into alkaline zinc-air microbattery measuring 1 cm2 area x ca. 305 µm thick. The use of inorganic MCM-41 membrane separator enables the fabrication of a compact cell design. The quality of the electrodeposited zinc electrodes is gauged directly from the electrochemical performance of zinc-air cell. Zinc electrodeposits prepared from electrolytic bath of 2 M NH4Cl produces the highest discharge capacity.ABSTRAK: Elektrod zink dengan kadar discas tinggi telah dihasilkan dengan proses saduran elektrokimia. Takungan elektrolit terdiri daripada zink klorida sebagai sumber logam dan ammonium klorida sebagai elektrolit sokongan. Kepekatan elektrolit sokongan diubah daripada sifar hingga 4 M, sementara kepekatan zink klorida ditetapkan pada 2 M. Ini bertujuan untuk mendapatkan saduran zink yang poros dengan luas permukaan per unit isipadu dan sentuhan antaramuka yang dipertingkatkan. Ciri-ciri ini akan menyumbang terhadap pengurangan kehilangan disebabkan kerintangan, pertambahan dalam gunapakai bahan aktif dan akhirnya menghasilkan sel elektrokimia berprestasi tinggi. Physisorpsi nitrogen pada 77 K telah digunakan untuk mengukur luas permukaan BET dan isipadu liang

Influence of Bath Composition at Acidic pH on Electrodeposition of Nickel-Layered Silicate Nanocomposites for Corrosion Protection

Directory of Open Access Journals (Sweden)

Jeerapan Tientong

2013-01-01

Full Text Available Nickel-layered silicates were electrochemically deposited from acidic bath solutions. Citrate was used as a ligand to stabilize nickel (II ions in the plating solution. The silicate, montmorillonite, was exfoliated by stirring in aqueous solution over 24 hours. The plating solutions were analyzed for zeta-potential, particle size, viscosity, and conductivity to investigate the effects of the composition at various pHs. The solution particles at pH 2.5 (−22.2 mV and pH 3.0 (−21.9 mV were more stable than at pH 1.6 (−10.1 mV as shown by zeta-potential analysis of the nickel-citrate-montmorillonite plating solution. Ecorr for the films ranged from −0.32 to −0.39 V with varying pH from 1.6 to 3.0. The films were immersed in 3.5% NaCl and the open circuit potential monitored for one month. The coatings deposited at pH 3.0 were stable 13 days longer in the salt solution than the other coatings. X-ray diffraction showed a change in the (111/(200 ratio for the coatings at the various pHs. The scanning electron microscopy and hardness results also support that the electrodeposition of nickel-montmorillonite at pH 3.0 (234 GPa had improved hardness and morphology compared to pH 2.5 (174 GPa and pH 1.6 (147 GPa.

Nickel coating on high strength low alloy steel by pulse current deposition

Science.gov (United States)

Nigam, S.; Patel, S. K.; Mahapatra, S. S.; Sharma, N.; Ghosh, K. S.

2015-02-01

Nickel is a silvery-white metal mostly used to enhance the value, utility, and lifespan of industrial equipment and components by protecting them from corrosion. Nickel is commonly used in the chemical and food processing industries to prevent iron from contamination. Since the properties of nickel can be controlled and varied over broad ranges, nickel plating finds numerous applications in industries. In the present investigation, pulse current electro-deposition technique has been used to deposit nickel on a high strength low alloy (HSLA) steel substrate.Coating of nickel is confirmed by X-ray diffraction (XRD) and EDAX analysis. Optical microscopy and SEM is used to assess the coating characteristics. Electrochemical polarization study has been carried out to study the corrosion behaviour of nickel coating and the polarisation curves have revealed that current density used during pulse electro-deposition plays a vital role on characteristics of nickel coating.

Electrodeposited nickel-cobalt sulfide nanosheet on polyacrylonitrile nanofibers: a binder-free electrode for flexible supercapacitors

Science.gov (United States)

Kamran Sami, Syed; Siddiqui, Saqib; Tajmeel Feroze, Muhammad; Chung, Chan-Hwa

2017-11-01

To pursue high-performance energy storage devices with both high energy density and power density, one-dimensional (1D) nanostructures play a key role in the development of functional devices including energy conversion, energy storage, and environmental devices. The polyacrylonitrile (PAN) nanofibers were obtained by the versatile electrospinning method. An ultra-thin nickel-cobalt sulfide (NiCoS) layer was conformably electrodeposited on a self-standing PAN nanofibers by cyclic voltammetry to fabricate the light-weighted porous electrodes for supercapacitors. The porous web of PAN nanofibers acts as a high-surface-area scaffold with significant electrochemical performance, while the electrodeposition of metal sulfide nanosheet further enhances the specific capacitance. The fabricated NiCoS on PAN (NiCoS/PAN) nanofibers exhibits a very high capacitance of 1513 F g-1 at 5 A g-1 in 1 M potassium chloride (KCl) aqueous electrolyte with superior rate capability and excellent electrochemical stability as a hybrid electrode. The high capacitance of the NiCoS is attributed to the large surface area of the electrospun PAN nanofibers scaffold, which has offered a large number of active sites for possible redox reaction of ultra-thin NiCoS layer. Benefiting from the compositional features and electrode architectures, the hybrid electrode of NiCoS/PAN nanofibers shows greatly improved electrochemical performance with an ultra-high capacitance (1124 F g-1 at 50 A g-1). Moreover, a binder-free asymmetric supercapacitor device is also fabricated by using NiCoS/PAN nanofibers as the positive electrode and activated carbon (MSP-20) on PAN nanofibers as the negative electrode; this demonstrates high energy density of 56.904 W h kg-1 at a power density of 1.445 kW kg-1, and it still delivers the energy density of 33.3923 W h kg-1 even at higher power density of 16.5013 kW kg-1.

THE INVESTIGATION OF INFLUENCE OF LASER RADIATION ON THE STRUCTURE AND MECHANICAL PROPERTIES OF COMPOSITE ELECTROLYTIC NICKEL COATING

Directory of Open Access Journals (Sweden)

V. A. Zabludovsky

2013-09-01

Full Text Available Purpose. Investigation of laser radiation effect on the structure and mechanical properties of electrodeposited nickel composite coatings containing ultrafine diamonds. Methodology. Electrodeposition of nickel films was carried out with the addition of a standard solution of ultrafine diamonds (UFD on laser-electrolytic installation, built on the basis of the gas-discharge CO2 laser. Mechanical testing the durability of coatings were performed on a machine with reciprocating samples in conditions of dry friction against steel. The spectral microanalysis of the elemental composition of the film - substrate was performed on REMMA-102-02. Findings. Research of nickel coatings and modified ultrafine diamond electrodeposited under external stimulation laser demonstrated the dependence of the structure and mechanical properties of composite electrolytic coating (CEC, and the qualitative and quantitative distribution of nanodiamond coprecipitated from an electrodeposition method. Originality. The effect of laser light on the process of co-precipitation of the UFD, which increases the micro-hardness and wear resistance of electrolytic nickel coatings was determined. Practical value. The test method of laser-stimulated composite electrolytic nickel electrodeposition coating is an effective method of local increase in wear resistance of metal coatings, which provides durability save performance (functional properties of the surface.

Alteration of corrosion and nanomechanical properties of pulse electrodeposited Ni/SiC nanocomposite coatings

Energy Technology Data Exchange (ETDEWEB)

Zarghami, V. [Department of Materials Science and Engineering, Sharif University of Technology, Azadi Street, Tehran (Iran, Islamic Republic of); Ghorbani, M., E-mail: Ghorbani@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, Azadi Street, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Azadi Street, Tehran (Iran, Islamic Republic of)

2014-06-15

Highlights: • Preparing Ni/SiC coatings on the Cu substrate by using of rotating disk electrode. • Optimizing of pulse current density parameters. • Optimizing of SiC content in the bath. • Investigation the effect of codeposited SiC amount on the properties of coatings. - Abstract: Nickel/silicon carbide composite electrodeposits were prepared on a rotating disk electrode (RDE), under pulse current condition. The effect of pulse parameters, current density, SiC content in the electrolyte on the codeposition of SiC were studied. Afterwards, the effect of codeposited SiC amount was investigated on electrochemical behavior and nanomechanical properties of coatings. The coatings were analyzed with Scanning Electron Microscopy (SEM), linear polarization, nanoindentation and Atomic Force Microscopy (AFM). The Ni–SiC electrocomposites, prepared at optimum conditions, exhibited improved nanomechanical properties in comparison to pure nickel electrodeposits. With increasing current density the morphology changed from flat surface to cauliflower structure. The Ni–SiC electrocomposites exhibited improved nanomechanical properties and corrosion resistances in comparison to pure nickel electrodeposits and these properties were improving with increasing codeposited SiC particles in electrocomposites.

Sulfiphilic nickel phosphosulfide enabled Li_2S impregnation in 3D graphene cages for Li-S batteries

International Nuclear Information System (INIS)

Zhou, Guangmin; Sun, Jie; Jin, Yang; Chen, Wei; Zu, Chenxi

2017-01-01

A 3D graphene cage with a thin layer of electrodeposited nickel phosphosulfide for Li_2S impregnation, using ternary nickel phosphosulphide as a highly conductive coating layer for stabilized polysulfide chemistry, is accomplished by the combination of theoretical and experimental studies. As a result, the 3D interconnected graphene cage structure leads to high capacity, good rate capability and excellent cycling stability in a Li_2S cathode.

Nickel coating electroplated characterization with and without carbon nanotubes; Caracterizacao de niquel eletrodepositado na presenca de nanotubos de carbono

Energy Technology Data Exchange (ETDEWEB)

Lopes, A C; Banczek, E P; Cunha, M T; Rodrigues, P R.P. [Universidade Estadual do Centro-Oeste, Guarapuava, PR (Brazil). Dept. de Quimica; Costa, I [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Terada, M [Universidade de Sao Paulo (EPUSP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

2010-07-01

The metals have great application, but when their properties are not suitable they should be improved through treatments to increase corrosion resistance, mechanical and wear. The metals electrodeposition such as nickel is one of treatment options. This study aims the development a nickel coating with and without (CNT), obtained by electrodeposition on aluminum alloy AA6061. The nickel electrodeposition was performed with cyclic voltammetry and chronoamperometry. Open circuit potential and anodic polarization curves were carried out samples characterization. The microstructure and the chemical composition of the M{sub x}O{sub z} coating were studied using the scanning electron microscopy, energy dispersion spectroscopy and X-ray diffraction. The results indicated that the nickel coating improve the corrosion resistance of aluminum in the presence of CNT. (author)

Electrodeposition and Properties of Copper Layer on NdFeB Device

Directory of Open Access Journals (Sweden)

LI Yue

2017-06-01

Full Text Available To decrease the impact of the regular Ni/Cu/Ni coating on the magnetic performance of sintered NdFeB device, alkaline system of HEDP complexing agent was applied to directly electro-deposit copper layer on NdFeB matrix, then nickel layer was electrodeposited on the copper layer and Cu/Ni coating was finally obtained to replace the regular Ni/Cu/Ni coating. The influence of concentration of HEDP complexing agent on deposition course was tested by electrochemical testing; morphology of copper layer was characterized by SEM, XRD and TEM; the binding force of copper layer and the thermal reduction of magnetic of NdFeB caused by electrodeposited coating were respectively explored through the thermal cycle test and thermal demagnetization test. The results show that the concentration of HEDP has great impact on the deposition overpotential of copper. In the initial electrodepositing stage, copper particles precipitate at the grain boundaries of NdFeB magnets with a preferred (111 orientation. The copper layer is compact and has enough binding force with the NdFeB matrix to meet the requirements in SJ 1282-1977. Furthermore, the thermal demagnetization loss rate of the sintered NdFeB with the protection of Cu/Ni coating is significantly less than that with the protection of Ni/Cu/Ni coating.

A uric acid sensor based on electrodeposition of nickel hexacyanoferrate nanoparticles on an electrode modified with multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Fang, B.; Feng, Y.; Wang, G.; Zhang, C.; Gu, A.; Liu, M.

2011-01-01

An electrode sensitive to uric acid was prepared by electrodeposition of nickel(II) hexacyanoferrate(III) on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes. The morphology of the material was characterized by scanning electron microscopy and Fourier transform infrared spectrometry. The modified electrode were characterized via cyclic voltammetry and amperometry (i - t). It exhibited efficient electron transfer ability and a strong and fast (< 3 s) response towards uric acid which is linear in the range from 0.1 μM to 18 μM, with a lower detection limit of 50 nM (at an S/N ratio of 3). In addition, the electrode exhibited good reproducibility and long-term stability. (author)

Magnetoelectric Effect in Gallium Arsenide-Nickel-Tin-Nickel Multilayer Structures

Science.gov (United States)

Filippov, D. A.; Tikhonov, A. A.; Laletin, V. M.; Firsova, T. O.; Manicheva, I. N.

2018-02-01

Experimental data have been presented for the magnetoelectric effect in nickel-tin-nickel multilayer structures grown on a GaAs substrate by cathodic electrodeposition. The method of fabricating these structures has been described, and the frequency dependence of the effect has been demonstrated. It has been shown that tin used as an intermediate layer reduces mechanical stresses due to the phase mismatch at the Ni-GaAs interface and, thus, makes it possible to grow good structures with a 70-μm-thick Ni layer. The grown structures offer good adhesion between layers and a high Q factor.

Characterization of thin Zn-Ni alloy coatings electrodeposited on low carbon steel

International Nuclear Information System (INIS)

El Hajjami, A.; Gigandet, M.P.; De Petris-Wery, M.; Catonne, J.C.; Duprat, J.J.; Thiery, L.; Raulin, F.; Pommier, N.; Starck, B.; Remy, P.

2007-01-01

The characteristics of initial layer formation in alkaline bath for Zn-Ni (12-15%) alloy electrodeposition on low carbon steel plates are detected in a nanometric thickness range by electron probe microanalysis (EPMA), with both bulk sample and thin film on substrate correction procedure, glow discharge optical emission spectroscopy (GDOES) and gracing incidence X-ray diffraction (GIXRD). The Zn-Ni coatings were elaborated using either intensiostatic or potentiostatic mode. A preferential deposition of Ni, in the initial thin layer, is detected by these analyses; according to EPMA and GDOES measurements, a layer rich in nickel at the interface substrate/deposit is observed (90 wt.% Ni) and approved by GIXRD; the thin layer of Ni formed in the first moments of electrolysis greatly inhibits the Zn deposition. The initial layer depends upon the relative ease of hydrogen and metal discharge and on the different substrate surfaces involved. The electrodeposition of zinc-nickel alloys in the first stage is a normal phenomenon of codeposition, whereby nickel - the more noble metal - is deposited preferentially

Nanocrystalline electrodeposited Ni-Mo-C cathodes for hydrogen production

International Nuclear Information System (INIS)

Hashimoto, K.; Sasaki, T.; Meguro, S.; Asami, K.

2004-01-01

Tailoring active nickel alloy cathodes for hydrogen evolution in a hot concentrated hydroxide solution was attempted by electrodeposition. The carbon addition to Ni-Mo alloys decreased the nanocrystalline grain size and remarkably enhanced the activity for hydrogen evolution, changing the mechanism of hydrogen evolution. The Tafel slope of hydrogen evolution was about 35 mV per decade. This suggested that the rate-determining step is desorption of adsorbed hydrogen atoms by recombination. As was distinct from the binary Ni-Mo alloys, after open circuit immersion, the overpotential, that is, the activity of nanocrystalline Ni-Mo-C alloys for hydrogen evolution was not changed, indicating the sufficient durability in the practical electrolysis

Protection of uranium by electrodeposition of nickel and diffusion

International Nuclear Information System (INIS)

Chauvin, G.; Coriou, H.; Hure, J.

1959-01-01

This work forms part of the overall scheme for investigating uranium canning for nuclear reactors. It is necessary to: - Protect the fuel (uranium) against corrosion by the cooling medium (heavy water, CO 2 , etc.), in the case of a rupture of the can; - Avoid dangerous U-Al diffusion (when it is question of an aluminium can) by using an intermediate layer of a metal whose rate of diffusion in uranium is very much less than that of aluminium under the same conditions. In the present work based on the use of an intermediate layer of nickel the following points are apparent: 1) After having treated the uranium surface it is possible to electroplate nickel on it in such a way that after annealing without the application of any pressure these deposits give a very good intermetallic U-Ni diffusion. Though this diffusion is inferior to that of the UAl system, it enables the protection to be reinforced and thus the corrosion resistance to be increased. 2) When no other factor varies, the experiments show that the quality of the diffusion zones obtained depends on the nature of the electrolytic nickel bath. 3) The classical nickel baths used previously for this type of work contain 20 to 40 g/l of boric acid acting as an electrolytic buffer. As a result of this, the deposits are highly contaminated by boron (400 to 500 ppm of boron). We shall show that with a bath which does not contain nuclear poisons, a very clean U-Ni diffusion zone can be obtained. 4) After annealing for 100 hours at 700 deg. C, microscopic examination of the diffusion front reveals the existence of five layers under bright field illumination and six Layers in polarised light: at least four of these layers are well crystallised. 5) Important irregularities in the interface between uranium and the first intermetallic compound U 6 Ni seem to be result of barriers to the diffusion caused by certain impurities in the uranium. 6) Of the seven definite compounds which can be formed during the diffusion, that

Process for electroforming nickel containing dispersed thorium oxide particles therein

International Nuclear Information System (INIS)

Malone, G.A.

1975-01-01

Nickel electroforming is effected by passing a direct current through a bath containing a dissolved nickel salt or a mixture of such salts, such as those present in sulfamate or Watts baths, and finely divided sol-derived thorium oxide particles of 75 to 300 angstroms, preferably 100 to 200 angstroms diameters therein, at a pH in the range of 0.4 to 1.9, preferably 0.8 to 1.3. The nickel so deposited, as on a pre-shaped stainless steel cathode, may be produced in desired shape and may be removed from the cathode and upon removal, without additional working, possesses desirable engineering properties at elevated temperatures, e.g., 1,500 to 2,200 0 F. Although the material produced is of improved high temperature stability, hardness, and ductility, compared with nickel alone, it is still ductile at room temperature and has properties equivalent or superior to nickel at room temperatures up to 1,500 0 F. Further improvements in mechanical properties of the material may be obtained by working. Also disclosed are electrodeposition baths, methods for their manufacture, and products resulting from the electrodeposition process. (U.S.)

Effects of choline chloride on electrodeposited Ni coating from a Watts-type bath

Science.gov (United States)

Wang, Yurong; Yang, Caihong; He, Jiawei; Wang, Wenchang; Mitsuzak, Naotoshi; Chen, Zhidong

2016-05-01

Electrodeposition of bright nickel (Ni) was carried out in a Watts-type bath. Choline chloride (ChCl) was applied as a multifunctional additive and substitute for nickel chloride (NiCl2) in a Watts-type bath. The function of ChCl was investigated through conductivity tests, anodic polarization, and cathodic polarization experiments. The studies revealed that ChCl performed well as a conducting salt, anodic activator, and cathodic inhibitor. The effects of ChCl on deposition rate, preferred orientation, grain size, surface morphology, and microhardness of Ni coatings were also studied. The deposition rate reached a maximum value of greater than 27 μm h-1 when 20 g L-1 ChCl was introduced to the bath. Using X-ray diffraction, it was confirmed that progressive addition of ChCl promoted the preferred crystal orientation modification from (2 0 0) and (2 2 0) to (1 1 1), refined grain size, and enhanced microhardness. The presence of ChCl lowered the roughness of the coating.

Effect of cobalt content on wear and corrosion behaviors of electrodeposited Ni-Co/WC nano-composite coatings.

Science.gov (United States)

Amadeh, A; Ebadpour, R

2013-02-01

Metal-ceramic composite coatings are widely used in automotive and aerospace industries as well as micro-electronic systems. Electrodeposition is an economic method for application of these coatings. In this research, nickel-cobalt coatings reinforced by nano WC particles were applied on carbon steel substrate by pulse electrodeposition from modified Watts bath containing different amounts of cobalt sulphate as an additive. Saccharin and sodium dodecyl sulphate (SDS) were also added to electroplating bath as grain refiner and surfactant, respectively. The effect of cobalt content on wear and corrosion behavior of the coatings was investigated. Wear and corrosion properties were assessed by pin-on-disk and potentiodynamic polarization methods, respectively. Phase analysis was performed by X-ray diffraction (XRD) using CuK(alpha) radiation and the worn surfaces were studied by means of Scanning Electron Microscopy (SEM). The results showed that the addition of cobalt improved the wear resistance of the coatings. In the presence of 18 g/L cobalt in electrodeposition bath, the wear rate of the coating decreased to 0.002 mg/m and the coefficient of friction reduced to 0.695 while they were 0.004 mg/m and 0.77 in the absence of cobalt, respectively. This improvement in wear properties can be attributed to the formation of hcp phase in metallic matrix. Meanwhile, the corrosion resistance of the coatings slightly reduced because cobalt is more active metal with respect to nickel.

Electrodeposition and Corrosion Resistance of Ni-Graphene Composite Coatings

Science.gov (United States)

Szeptycka, Benigna; Gajewska-Midzialek, Anna; Babul, Tomasz

2016-08-01

The research on the graphene application for the electrodeposition of nickel composite coatings was conducted. The study assessed an important role of graphene in an increased corrosion resistance of these coatings. Watts-type nickel plating bath with low concentration of nickel ions, organic addition agents, and graphene as dispersed particles were used for deposition of the composite coatings nickel-graphene. The results of investigations of composite coatings nickel-graphene deposited from the bath containing 0.33, 0.5, and 1 g/dm3 graphene and one surface-active substance were shown. The contents of particles in coatings, the surface morphology, the cross-sectional structures of the coated samples, and their thickness and the internal stresses were studied. Voltammetric method was used for examination of the corrosion resistance of samples of composite coatings in 0.5 M NaCl. The obtained results suggest that the content of incorporated graphene particles increases with an increasing amount of graphene in plating bath. The application of organic compounds was advantageous because it caused compressive stresses in the deposited coatings. All of the nickel-graphene composite layers had better corrosion resistance than the nickel coating.

Microstructure and thermal stability of nickel layers electrodeposited from an additive-free sulphamate-based electrolyte

DEFF Research Database (Denmark)

Rasmussen, Anette Alsted; Møller, Per; Somers, Marcel A. J.

2006-01-01

and scanning electron microscopy and X-ray diffraction; the Vickers hardness was measured in cross sections. The present is meant as a reference for forthcoming articles on the investigation of various strengthening mechanisms on the microstructure, hardness and thermal stability of Ni (alloys) electrodeposits.......The influences of the current density and the temperature on the microstructure and hardness of Ni layers electrodeposited from an additive-free sulphamate bath were investigated. The microstructure and thermal stability of the electrodeposits was investigated with a combination of transmission...

Monodispersed macroporous architecture of nickel-oxide film as an anode material for thin-film lithium-ion batteries

International Nuclear Information System (INIS)

Wu, Mao-Sung; Lin, Ya-Ping

2011-01-01

A nickel-oxide film with monodispersed open macropores was prepared on a stainless-steel substrate by electrophoretic deposition of a polystyrene-sphere monolayer followed by anodic electrodeposition of nickel oxy-hydroxide. The deposited films convert to cubic nickel oxide after annealing at 400 o C for 1 h. Galvanostatic charge and discharge results indicate that the nickel-oxide film with monodispersed open macropores is capable of delivering a higher capacity than the bare nickel-oxide film, especially in high-rate charge and discharge processes. The lithiation capacity of macroporous nickel oxide reaches 1620 mA h g -1 at 1 C current discharge and decreases to 990 mA h g -1 at 15 C current discharge. The presence of monodispersed open macropores in the nickel-oxide film might facilitate the electrolyte penetration, diffusion, and migration. Electrochemical reactions between nickel oxide and lithium ions are therefore markedly improved by this tailored film architecture.

Nickel and titanium nanoboride composite coating

International Nuclear Information System (INIS)

Efimova, K A; Galevsky, G V; Rudneva, V V; Kozyrev, N A; Orshanskaya, E G

2015-01-01

Electrodeposition conditions, structural-physical and mechanical properties (microhardness, cohesion with a base, wear resistance, corrosion currents) of electroplated composite coatings on the base of nickel with nano and micro-powders of titanium boride are investigated. It has been found out that electro-crystallization of nickel with boride nanoparticles is the cause of coating formation with structural fragments of small sizes, low porosity and improved physical and mechanical properties. Titanium nano-boride is a component of composite coating, as well as an effective modifier of nickel matrix. Nano-boride of the electrolyte improves efficiency of the latter due to increased permissible upper limit of the cathodic current density. (paper)

Effect of different nickel precursors on capacitive behavior of electrodeposited NiO thin films

Energy Technology Data Exchange (ETDEWEB)

Kore, R. M.; Ghadge, T. S.; Ambare, R. C.; Lokhande, B. J., E-mail: bjlokhande@yahoo.com [School of Physical Sciences, Solapur University, Solapur-413 255, M.S. (India)

2016-04-13

In the present study, the effect of nickel precursors containing different anions like nitrate, chloride and sulphate on the morphology and pseudocapacitance behavior of NiO is investigated. The NiO samples were prepared by using a potentiondynamic electrodeposition technique in the three electrode cell. Cyclic voltammetry technique was exploited for potentiodynamic deposition of the films. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. The XRD reveals the cubic crystal structure for all samples. The SEM micrograph shows nanoflakelike, up grown nanoflakes and honeycomb like nanostructured morphologies for nitrate, chloride and sulphate precursors respectively. The capacitive behavior of these samples was recorded using cyclic voltammetry (CV), charge-discharge and electrochemical impedance spectroscopy (EIS) in 1 M KOH electrolyte. The specific capacitance values of NiO samples obtained using CV for nitrate, chloride and sulphate precursors were 136, 214 and 893 Fg{sup −1} respectively, at the scan rate of 5 mVs{sup −1}. The charge discharge study shows high specific energy for the sample obtained from sulphate (23.98 Whkg{sup −1}) as compared to chloride (9.67 Whkg{sup −1}) and nitrate (4.9 Whkg{sup −1}), whereas samples of cholride (13.9 kWkg{sup −1} and nitrate (10.5 kWkg{sup −1}) shows comparatively more specific power than samples obtained from sulphate (7.6 kWkg{sup −1}). The equivalent series resistance of NiO samples observed from EIS study are 1.34, 1.29 and 1.27 Ω respectively for nitrate, chloride and sulphate precursors. These results emphasizes that the samples obtained from sulphate precursors provides very low impedance through honeycomb like nanostructured morphology which supports good capacitive behavior of NiO.

Electrochemical and surface characterisation of oxide films on nano-grain nickel films electrodeposited on INCOLOY-800

International Nuclear Information System (INIS)

Navin Vinayak, S.; Sunitha, Y.; Rangarajan, S.; Narasimhan, S.V.

2008-01-01

Nano materials have different properties from the corresponding bulk materials because of fine grain size, large fraction of surface atoms, high surface energy and high grain boundary volume fraction. For similar reasons, the nano-alloy coatings show superior high-temperature corrosion resistance and are generally more resistant to stress corrosion cracking. Hence, it is of interest to know the materials performance, if the structural materials used in nuclear reactors are made of nano-grains. In Indian PHWRs, Incoloy-800 is being used as the steam generator tubing material. It's corrosion resistance property is very important as it forms not only the pressure boundary between the radioactive primary water and non-active secondary water but also from the view point of loss of heavy water, in case of any corrosion damage. In this paper, the corrosion resistance of the oxide films formed on nano-grain nickel film electrodeposited on Incoloy-800 (a) in the presence of saccharine (WS) and (b) in the absence of saccharine (WOS) were compared with that formed on Commercial Ni foil, using electrochemical dc polarization and ac impedance techniques. The surface morphology, elemental analysis and grain size were studied with SEM, EDX and XRD techniques respectively. The nano-grain nickel films were prepared on Incoloy-800 by electrodeposition using Watt's Bath with saccharine sodium as a surfactant. The oxide films were developed by exposing them to LiOH solution (pH-10.0) at 245 deg C for 3 days (A-group) and 7 days (B-group). XRD results showed that the grain size of Ni formed in the absence of saccharine (WOS) was ∼ 60 nm and did not change after being autoclaved. But, for Ni formed in the presence of saccharine (WS), the grain size was ∼ 16 nm which increased to 40-50 nm after being autoclaved. With both A and B-group specimens, the PDAP curves showed an active-passive transition, a passive region and a transpassive region in 2N H 2 SO 4 . However, the critical

Preliminary study on auto-electrodeposition of copper, cadmium, nickel, and cobalt in acid and glycerol medium

Directory of Open Access Journals (Sweden)

S.G. Viswanath

2013-12-01

Full Text Available Electrodeposition can be carried out even without corresponding metal ions in the solution, but the respective metal electrode acts as anode. This process is called auto-electrodeposition. It occurs under similar conditions applied for electrowinning or electrodeposition. The electrochemical mechanism of electrowinning and autoelectrodeposition is suggested. Hydroxyl ions play very important role in this process. In this process, a black loss deposit is formed on the anode metal. The autoelectrodeposition is combination of electrodissolution process and electrowinning process.

The electrochemical deposition of tin-nickel alloys and the corrosion properties of the coating

DEFF Research Database (Denmark)

Jellesen, Morten Stendahl; Møller, Per

2005-01-01

The electrodeposition of tin/nickel (65/35 wt%) is a unique coating process because of the deposition of an intermetallic phase of nickel and tin, which cannot be formed by any pyrometallurgical process. From thermodynamic calculations it can be shown that intermetallic phases can be formed throu...

In situ Ni-doping during cathodic electrodeposition of hematite for excellent photoelectrochemical performance of nanostructured nickel oxide-hematite p-n junction photoanode

Science.gov (United States)

Phuan, Yi Wen; Ibrahim, Elyas; Chong, Meng Nan; Zhu, Tao; Lee, Byeong-Kyu; Ocon, Joey D.; Chan, Eng Seng

2017-01-01

Nanostructured nickel oxide-hematite (NiO/α-Fe2O3) p-n junction photoanodes synthesized from in situ doping of nickel (Ni) during cathodic electrodeposition of hematite were successfully demonstrated. A postulation model was proposed to explain the fundamental mechanism of Ni2+ ions involved, and the eventual formation of NiO on the subsurface region of hematite that enhanced the potential photoelectrochemical water oxidation process. Through this study, it was found that the measured photocurrent densities of the Ni-doped hematite photoanodes were highly dependent on the concentrations of Ni dopant used. The optimum Ni dopant at 25 M% demonstrated an excellent photoelectrochemical performance of 7-folds enhancement as compared to bare hematite photoanode. This was attributed to the increased electron donor density through the p-n junction and thus lowering the energetic barrier for water oxidation activity at the optimum Ni dopant concentration. Concurrently, the in situ Ni-doping of hematite has also lowered the photogenerated charge carrier transfer resistance as measured using the electrochemical impedance spectroscopy. It is expected that the fundamental understanding gained through this study is helpful for the rational design and construction of highly efficient photoanodes for application in photoelectrochemical process.

Influence of 1,3,6 naphthalene trisulfonic acid on microstructure & hardness in electrodeposited Ni-layers

DEFF Research Database (Denmark)

Rasmussen, Anette Alsted; Møller, Per; Somers, Marcel A. J.

2002-01-01

The influence of the additive 1,3,6 naphthalene trisulfonic acid on the microstructure and hardness of electrodeposited nickel layers was investigated. The microstructure was characterized using transmission electron microscopy; the Vickers hardness was measured in cross sections. The additive wa...

Initial study of Nickel Electrolyte for EnFACE Process

Directory of Open Access Journals (Sweden)

Tri Widayatno

2015-03-01

Full Text Available Nickel electrolyte for a micro-pattern transfer process without photolithography, EnFACE, has been developed. Previous work on copper deposition indicated that a conductivity of ~2.7 Sm-1 is required. Electrochemical parameters of electrolyte i.e. current density and overpotential are also crucial to govern a successful pattern replication. Therefore, the investigation focused on the measurement of physicochemical properties and electrochemical behaviour of the electrolyte at different nickel concentrations and complexing agents of chloride and sulfamate. Nickel electrolytes containing sulfamate, chloride and combined sulfamate-chloride with concentrations between 0.14 M and 0.3 M were investigated. Physicochemical properties i.e. pH and conductivity were measured to ensure if they were in the desired value. The electrochemical behaviour of the electrolytes was measured by polarisation experiments in a standard three-electrode cell. The working electrode was a copper disc (surface area of 0.196 cm2 and the counter electrode was platinum mesh. The potential was measured againts a saturated calomel reference electrode (SCE. The experiments were carried out at various scan rate and Rotating Disc Electrode (RDE rotation speed to see the effect of scan rate and agitation. Based on the measured physicochemical properties, the electrolyte of 0.19 M nickel sulfamate was chosen for experimentation. Polarisation curve of agitated solution suggested that overall nickel electrodeposition reaction is controlled by a combination of kinetics and mass transfer.  Reduction potential of nickel was in the range of -0.7 to -1.0 V. The corresponding current densities for nickel deposition were in the range of -0.1 to -1.5 mA cm-2.

Residual stress in Ni-W electrodeposits

DEFF Research Database (Denmark)

Mizushima, Io; Tang, Peter Torben; Hansen, Hans Nørgaard

2006-01-01

In the present work, the residual stress in Ni–W layers electrodeposited from electrolytes based on NiSO4 and Na2WO4, is investigated. Citrate, glycine and triethanolamine were used as complexing agents, enabling complex formation between the nickel ion and tungstate. The results show that the type...... of complexing agent and the current efficiency have an influence on the residual stress. In all cases, an increase in tensile stress in the deposit with time after deposition was observed. Pulse plating could improve the stress level for the electrolyte containing equal amounts of citrate...

Process for forming a nickel foil with controlled and predetermined permeability to hydrogen

Science.gov (United States)

Engelhaupt, Darell E.

1981-09-22

The present invention provides a novel process for forming a nickel foil having a controlled and predetermined hydrogen permeability. This process includes the steps of passing a nickel plating bath through a suitable cation exchange resin to provide a purified nickel plating bath free of copper and gold cations, immersing a nickel anode and a suitable cathode in the purified nickel plating bath containing a selected concentration of an organic sulfonic acid such as a napthalene-trisulfonic acid, electrodepositing a nickel layer having the thickness of a foil onto the cathode, and separating the nickel layer from the cathode to provide a nickel foil. The anode is a readily-corrodible nickel anode. The present invention also provides a novel nickel foil having a greater hydrogen permeability than palladium at room temperature.

Process for forming a nickel foil with controlled and predetermined permeability to hydrogen

International Nuclear Information System (INIS)

Engelhaupt, D. E.

1981-01-01

The present invention provides a novel process for forming a nickel foil having a controlled and predetermined hydrogen permeability. This process includes the steps of passing a nickel plating bath through a suitable cation exchange resin to provide a purified nickel plating bath free of copper and gold cations, immersing a nickel anode and a suitable cathode in the purified nickel plating bath containing a selected concentration of an organic sulfonic acid such as a napthalene-trisulfonic acid, electrodepositing a nickel layer having the thickness of a foil onto the cathode, and separating the nickel layer from the cathode to provide a nickel foil. The anode is a readilycorrodible nickel anode. The present invention also provides a novel nickel foil having a greater hydrogen permeability than palladium at room temperature

Contribution to the study of the electrodeposition of iron-nickel alloys

International Nuclear Information System (INIS)

Valignat, J.

1968-01-01

Using a coulometric technique based upon the anodic intentiostatic dissolution, we studied the potentiostatic, deposition of nickel, iron and nickel iron alloys. We have shown that the minimum of the curve I = f (t) (deposition current versus time) is probably due to the transitory blocking of the surface by hydrogen and that the syn-crystallisation of nickel and iron is responsible for the anomalous co-deposition of these two elements. (author) [fr

Fabricating Copper Nanotubes by Electrodeposition

Science.gov (United States)

Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

2009-01-01

Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

The mechanism of cathodic electrodeposition of epoxy coatings and the corrosion behaviour of the electrodeposited

Directory of Open Access Journals (Sweden)

VESNA B. MISKOVIC-STANKOVIC

2002-05-01

Full Text Available The model of organic film growth on a cathode during electrodeposition process proposes the current density-time and film thickness-time relationships and enables the evaluation of the rate contants for the electrochemical reaction of OH– ion evolution and for the chemical reaction of organic film deposition. The dependences of film thickness and rate constants on the applied voltage, bath temperature and resin concentration in the electrodeposition bath have also been obtained. The deposition parameters have a great effect on the cathodic electrodeposition process and on the protective properties of the obtained electrodeposited coatings. From the time dependences of the pore resistance, coating capacitance and relative permittivity, obtained from impedance measurements, the effect of applied voltage, bath temperature and resin concentration on the protective properties of electrodeposited coatings has been shown. Using electrochemical impedance spectroscopy, thermogravimetric analysis, gravimetric liquid sorption experiments, differential scanning calorimetry and optical miscroscopy, the corrosion stability of epoxy coatings was investigated. A mechanism for the penetration of electrolyte through an organic coating has been suggested and the shape and dimensions of the conducting macropores have been determined. It was shown that conduction through a coating depends only on the conduction through the macropores, although the quantity of electrolyte in the micropores of the polymer net is about one order of magnitude greater than that inside the conducting macropores.

Synthesis and Performance Evaluation of Pulse Electrodeposited Ni-AlN Nanocomposite Coatings

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Kamran Ali

2018-01-01

Full Text Available This research work presents the microscopic analysis of pulse electrodeposited Ni-AlN nanocomposite coatings using SEM and AFM techniques and their performance evaluation (mechanical and electrochemical by employing nanoindentation and electrochemical methods. The Ni-AlN nanocomposite coatings were developed by pulse electrodeposition. The nickel matrix was reinforced with various amounts of AlN nanoparticles (3, 6, and 9 g/L to develop Ni-AlN nanocomposite coatings. The effect of reinforcement concentration on structure, surface morphology, and mechanical and anticorrosion properties was studied. SEM and AFM analyses indicate that Ni-AlN nanocomposite coatings have dense, homogenous, and well-defined pyramid structure containing uniformly distributed AlN particles. A decent improvement in the corrosion protection performance is also observed by the addition of AlN particles to the nickel matrix. Corrosion current was reduced from 2.15 to 1.29 μA cm−2 by increasing the AlN particles concentration from 3 to 9 g/L. It has been observed that the properties of Ni-AlN nanocomposite coating are sensitive to the concentration of AlN nanoparticles used as reinforcement.

Special features of nickel-molybdenum alloy electrodeposition onto screen-type cathodes

International Nuclear Information System (INIS)

Aleksandrova, G.S.; Varypaev, V.N.

1982-01-01

Electrolytic nickel-molybdenum alloy, which has a rather low hydrogen overpotential and high corrosion resistance, is of interest as cathode material in industrial electrolysis. Screen-type electrodes with a nickel-molybdenum coating can be used as nonconsumable cathodes in water-activated magnesium-alloy batteries

The use of stainless steel and nickel alloys as low-cost cathodes in microbial electrolysis cells

KAUST Repository

Selembo, Priscilla A.

2009-05-01

Microbial electrolysis cells (MECs) are used to produce hydrogen gas from the current generated by bacteria, but low-cost alternatives are needed to typical cathode materials (carbon cloth, platinum and Nafion™). Stainless steel A286 was superior to platinum sheet metal in terms of cathodic hydrogen recovery (61% vs. 47%), overall energy recovery (46% vs. 35%), and maximum volumetric hydrogen production rate (1.5 m3 m-3 day-1 vs. 0.68 m3 m-3 day-1) at an applied voltage of 0.9 V. Nickel 625 was better than other nickel alloys, but it did not perform as well as SS A625. The relative ranking of these materials in MEC tests was in agreement with cyclic voltammetry studies. Performance of the stainless steel and nickel cathodes was further increased, even at a lower applied voltage (0.6 V), by electrodepositing a nickel oxide layer onto the sheet metal (cathodic hydrogen recovery, 52%, overall energy recovery, 48%; maximum volumetric hydrogen production rate, 0.76 m3 m-3 day-1). However, performance of the nickel oxide cathodes decreased over time due to a reduction in mechanical stability of the oxides (based on SEM-EDS analysis). These results demonstrate that non-precious metal cathodes can be used in MECs to achieve hydrogen gas production rates better than those obtained with platinum. © 2009 Elsevier B.V. All rights reserved.

The use of stainless steel and nickel alloys as low-cost cathodes in microbial electrolysis cells

KAUST Repository

Selembo, Priscilla A.; Merrill, Mathew D.; Logan, Bruce E.

2009-01-01

Microbial electrolysis cells (MECs) are used to produce hydrogen gas from the current generated by bacteria, but low-cost alternatives are needed to typical cathode materials (carbon cloth, platinum and Nafion™). Stainless steel A286 was superior to platinum sheet metal in terms of cathodic hydrogen recovery (61% vs. 47%), overall energy recovery (46% vs. 35%), and maximum volumetric hydrogen production rate (1.5 m3 m-3 day-1 vs. 0.68 m3 m-3 day-1) at an applied voltage of 0.9 V. Nickel 625 was better than other nickel alloys, but it did not perform as well as SS A625. The relative ranking of these materials in MEC tests was in agreement with cyclic voltammetry studies. Performance of the stainless steel and nickel cathodes was further increased, even at a lower applied voltage (0.6 V), by electrodepositing a nickel oxide layer onto the sheet metal (cathodic hydrogen recovery, 52%, overall energy recovery, 48%; maximum volumetric hydrogen production rate, 0.76 m3 m-3 day-1). However, performance of the nickel oxide cathodes decreased over time due to a reduction in mechanical stability of the oxides (based on SEM-EDS analysis). These results demonstrate that non-precious metal cathodes can be used in MECs to achieve hydrogen gas production rates better than those obtained with platinum. © 2009 Elsevier B.V. All rights reserved.

Drying Rate of Carbonate of Nickel

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Ing. Aymara Ricardo-Riverón

2015-11-01

Full Text Available In the present work, the drying rate of carbonate of nickel was studied experimentally at the laboratory scale. The values of critical moisture are shown and the graphics: characteristic curve of drying rate and the moisture dependence of the time. Models ware obtained to estimate the slope of the constant - rate period and to the falling - rate period until the equilibrium humidity, in dependence of external factors: drying temperature, initial moisture and the pH of the slurry. The chemical composition of the carbonate didn't exercise effect statistically significant over the drying rate.

Fabrication and magnetization measurement of Ni thin films on silicon substrate by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Tang Yang [Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Graduate School of the Chinese Academy of Sciences (China); Zhao Dongxu [Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China)], E-mail: dxzhao2000@yahoo.com.cn; Shen Dezhen; Zhang Jiying; Li Binghui; Lu Youming; Fan Xiwu [Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China)

2008-02-29

Ni thin films were electrodeposited on n-Si (100) substrate from the electrolytes containing Ni(CH{sub 3}COO){sub 2} and CH{sub 3}COONH{sub 4} at room temperature. The scanning electron microscope images of the films reveals the uniform distribution of the nickel all over the substrate surface, which illustrates that the fine Ni films on large scales could be obtained through the method of electrodeposition. Vibrating sample magnetometer measurement with the applied field parallel to the surface shows obvious hysteresis loops of the magnetic thin films. The morphology and magnetism of the Ni thin films evolves with the deposition time increasing. The effect of deposition conditions on the properties of the Ni thin films is investigated.

Kinetics of Ni–Mo electrodeposition from Ni-rich citrate baths

International Nuclear Information System (INIS)

Beltowska-Lehman, E.; Indyka, P.

2012-01-01

The kinetics of Ni–Mo alloy electrodeposition on steel substrates from an aqueous citrate–ammonia complex baths has been investigated by means of steady-state polarisation measurements in a system with a rotating disc electrode (RDE). Partial current densities for discharge of Ni(II) and Mo(VI) ions and hydrogen evolution as a function of molybdate concentration in the bath, cathode potentials and the rate of mass transport were determined. It has been shown that – under all investigated conditions – Ni–Mo alloy deposition is more favourable than pure nickel and the cathodic process is strongly influenced by the Mo(VI) content in the solution. The Ni(II) electroreduction rate initially increases, as the cathode potential shifts towards more negative values and the concentration of molybdate grows in the solution. However, for the highest examined MoO 4 2− content, a considerable decrease in the rate of the process is subsequently observed at certain limit potentials, the values of which depend on molybdate concentration and hydrodynamic conditions. This effect, related to the formation of intermediate molybdenum oxides (characterised by very low overvoltage for hydrogen evolution), becomes less pronounced when the RDE rotation speed is increased. Hydrogen evolution is strongly associated with molybdenum deposition. An increase of the molybdate ions concentration in the bath, as well as an increase in the rate of mass transport, leads to an increase in Mo content in deposits and to the reduction of current efficiency. The Ni–Mo coatings electrodeposited from the designed bath (with the current efficiency of about 70%) containing about 30 wt.% Mo, are characterised by a shiny-grey appearance and good adhesion to the steel substrate. They are characterised by column growth and amorphous microstructure with randomly distributed nanocrystallites of the MoNi 4 intermetallic phase.

High Temperature Oxidation of Nickel-based Cermet Coatings Composed of Al2O3 and TiO2 Nanosized Particles

Science.gov (United States)

Farrokhzad, M. A.; Khan, T. I.

2014-09-01

New technological challenges in oil production require materials that can resist high temperature oxidation. In-Situ Combustion (ISC) oil production technique is a new method that uses injection of air and ignition techniques to reduce the viscosity of bitumen in a reservoir and as a result crude bitumen can be produced and extracted from the reservoir. During the in-situ combustion process, production pipes and other mechanical components can be exposed to air-like gaseous environments at extreme temperatures as high as 700 °C. To protect or reduce the surface degradation of pipes and mechanical components used in in-situ combustion, the use of nickel-based ceramic-metallic (cermet) coating produced by co-electrodeposition of nanosized Al2O3 and TiO2 have been suggested and earlier research on these coatings have shown promising oxidation resistance against atmospheric oxygen and combustion gases at elevated temperatures. Co-electrodeposition of nickel-based cermet coatings is a low-cost method that has the benefit of allowing both internal and external surfaces of pipes and components to be coated during a single electroplating process. Research has shown that the volume fraction of dispersed nanosized Al2O3 and TiO2 particles in the nickel matrix which affects the oxidation resistance of the coating can be controlled by the concentration of these particles in the electrolyte solution, as well as the applied current density during electrodeposition. This paper investigates the high temperature oxidation behaviour of novel nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in a nickel matrix and produced by coelectrodeposition technique as a function of the concentration of these particles in the electrolyte solution and applied current density. For this purpose, high temperature oxidation tests were conducted in dry air for 96 hours at 700 °C to obtain mass changes (per unit of area) at specific time

Nickel/Diamond Composite Coating Prepared by High Speed Electrodeposition

Directory of Open Access Journals (Sweden)

ZHANG Yan

2016-10-01

Full Text Available Nickel/diamond composite coatings were prepared on the basis of a new high speed electroplating bath. The influence of additives, plating parameters and diamond concentration on internal stress was investigated in order to find the solution to decrease the stress introduced by high current density; the micro morphology of the coatings were observed by SEM. The bath and depositing parameters were optimized that thick nickel/diamond composite coatings with low internal stress can be high speed electroplated with a high cathode current density of 30A/dm2. The results show that when plated with bath composition and parameters as follows: sodium dodecyl sulfate 0.5g/L, ammonium acetate 3g/L, sodium citrate 1.5g/L, diamond particles 30g/L; pH value 3-4, temperature 50℃, the composite coatings prepared in high speed have the lowest internal stress.

Microstructure and Properties of Ni and Ni/Al2O3 Coatings Electrodeposited at Various Current Densities

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Góral A.

2016-03-01

Full Text Available The study presents investigations of an influence of various direct current densities on microstructure, residual stresses, texture, microhardness and corrosion resistance of the nickel coatings electrodeposited from modified Watt’s baths. The properties of obtained coatings were compared to the nano-crystalline composite Ni/Al2O3 coatings prepared under the same plating conditions. The similarities and differences of the obtained coatings microstructures visible on both their surfaces and cross sections and determined properties were presented. The differences in the growth character of the Ni matrix and in the microstructural properties were observed. All electrodeposited Ni and Ni/Al2O3 coatings were compact and well adhering to the steel substrates. The thickness and the microhardness of the Ni and Ni/Al2O3 deposits increased significantly with the current density in the range 2 - 6 A/dm2. Residual stresses are tensile and they reduced as the current density increased. The composite coatings revealed better protection from the corrosion of steel substrate than pure nickel in solution 1 M NaCl.

Microstructural, phase evolution and corrosion properties of silicon carbide reinforced pulse electrodeposited nickel-tungsten composite coatings

Science.gov (United States)

Singh, Swarnima; Sribalaji, M.; Wasekar, Nitin P.; Joshi, Srikant; Sundararajan, G.; Singh, Raghuvir; Keshri, Anup Kumar

2016-02-01

Silicon carbide (SiC) reinforced nickel-tungsten (Ni-W) coatings were successfully fabricated on steel substrate by pulse electrodeposition method (PED) and the amount of SiC was varied as 0 g/l, 2 g/l, and 5 g/l in Ni-W coating. Effect of subsequent addition of SiC on microstructures, phases and on corrosion property of the coating was investigated. Field emission scanning electron microscopy (FE-SEM) image of the surface morphology of the coating showed the transformation from the dome like structure to turtle shell like structure. X-ray diffraction (XRD) of Ni-W-5 g/l SiC showed the disappearance of (220) plane of Ni(W), peak splitting in major peak of Ni(W) and formation of distinct peak of W(Ni) solid solution. Absence of (220) plane, peak splitting and presence of W(Ni) solid solution was explained by the high resolution transmission electron microscopy (HR-TEM) images. Tafel polarization plot was used to study the corrosion property of the coatings in 0.5 M NaCl solution. Ni-W-5 g/l SiC coating was showed higher corrosion resistance (i.e. ∼21% increase in corrosion potential, Ecorr) compared to Ni-W coating. Two simultaneous phenomena have been identified for the enhanced corrosion resistance of Ni-W-5 g/l SiC coating. (a) Presence of crystallographic texture (b) formation of continuous double barrier layer of NiWO4 and SiO2.

Fabrication and characterization of nickel nanowires deposited on metal substrate

International Nuclear Information System (INIS)

Rahman, I.Z.; Razeeb, K.M.; Rahman, M.A.; Kamruzzaman, Md.

2003-01-01

The present investigation is a part of ongoing systematic study of production and process development of nanometer scale arrays of magnetic wires on metal substrates. Nickel nanowires are grown in ordered anodic alumina templates using galvanostatic electrodeposition. In this paper we report on the growth of nanowires on the electrochemical cell parameters such as bath temperature, pH and time. Focused ion beam analysis revealed heterogeneous growth of nickel nanowires. X-ray diffraction spectrum showed that FCC nickel changed the preferred orientation from (2 2 0) at lower bath temperatures to (2 0 0) at higher bath temperatures. Magnetic measurement showed that coercive fields were higher for wires with smaller diameters. Magneto-impedance was measured as a function of applied magnetic field and wire diameter

Graphene hydrogels deposited in nickel foams for high-rate electrochemical capacitors.

Science.gov (United States)

Chen, Ji; Sheng, Kaixuan; Luo, Peihui; Li, Chun; Shi, Gaoquan

2012-08-28

Graphene hydrogel/nickel foam composite electrodes for high-rate electrochemical capacitors are produced by reduction of an aqueous dispersion of graphene oxide in a nickel foam (upper half of figure). The micropores of the hydrogel are exposed to the electrolyte so that ions can enter and form electrochemical double-layers. The nickel framework shortens the distances of charge transfer. Therefore, the electrochemical capacitor exhibits highrate performance (see plots). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zinc-Nickel Codeposition in Sulfate Solution Combined Effect of Cadmium and Boric Acid

Directory of Open Access Journals (Sweden)

Y. Addi

2011-01-01

Full Text Available The combined effect of cadmium and boric acid on the electrodeposition of zinc-nickel from a sulfate has been investigated. The presence of cadmium ion decreases zinc in the deposit. In solution, cadmium inhibits the zinc ion deposition and suppresses it when deposition potential value is more negative than −1.2 V. Low concentration of CdSO4 reduces the anomalous nature of Zn-Ni deposit. Boric acid decreases current density and shifts potential discharge of nickel and hydrogen to more negative potential. The combination of boric acid and cadmium increases the percentage of nickel in the deposit. Boric acid and cadmium.

In situ Ni-doping during cathodic electrodeposition of hematite for excellent photoelectrochemical performance of nanostructured nickel oxide-hematite p-n junction photoanode

Energy Technology Data Exchange (ETDEWEB)

Phuan, Yi Wen, E-mail: phuan.yi.wen@monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor DE 47500 (Malaysia); Ibrahim, Elyas, E-mail: meibr2@student.monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor DE 47500 (Malaysia); Chong, Meng Nan, E-mail: Chong.Meng.Nan@monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor DE 47500 (Malaysia); Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor DE 47500 (Malaysia); Zhu, Tao, E-mail: zhu.tao@monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor DE 47500 (Malaysia); Lee, Byeong-Kyu, E-mail: bklee@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Nam-gu, Daehakro 93, Ulsan 680-749 (Korea, Republic of); Ocon, Joey D., E-mail: jdocon@up.edu.ph [Laboratory of Electrochemical Engineering (LEE), Department of Chemical Engineering, University of the Philippines Diliman, Quezon City 1101 (Philippines); Chan, Eng Seng, E-mail: chan.eng.seng@monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor DE 47500 (Malaysia)

2017-01-15

Highlights: • NiO-hematite p-n junction photoanodes were fabricated via an in situ Ni-doping. • The fundamental mechanism of Ni{sup 2+} ions involved was elucidated. • The optimum Ni dopant was 25 M% for the highest photocurrent density. • It exhibited an excellent photoelectrochemical performance of 7-folds enhancement. - Abstract: Nanostructured nickel oxide-hematite (NiO/α-Fe{sub 2}O{sub 3}) p-n junction photoanodes synthesized from in situ doping of nickel (Ni) during cathodic electrodeposition of hematite were successfully demonstrated. A postulation model was proposed to explain the fundamental mechanism of Ni{sup 2+} ions involved, and the eventual formation of NiO on the subsurface region of hematite that enhanced the potential photoelectrochemical water oxidation process. Through this study, it was found that the measured photocurrent densities of the Ni-doped hematite photoanodes were highly dependent on the concentrations of Ni dopant used. The optimum Ni dopant at 25 M% demonstrated an excellent photoelectrochemical performance of 7-folds enhancement as compared to bare hematite photoanode. This was attributed to the increased electron donor density through the p-n junction and thus lowering the energetic barrier for water oxidation activity at the optimum Ni dopant concentration. Concurrently, the in situ Ni-doping of hematite has also lowered the photogenerated charge carrier transfer resistance as measured using the electrochemical impedance spectroscopy. It is expected that the fundamental understanding gained through this study is helpful for the rational design and construction of highly efficient photoanodes for application in photoelectrochemical process.

In situ Ni-doping during cathodic electrodeposition of hematite for excellent photoelectrochemical performance of nanostructured nickel oxide-hematite p-n junction photoanode

International Nuclear Information System (INIS)

Phuan, Yi Wen; Ibrahim, Elyas; Chong, Meng Nan; Zhu, Tao; Lee, Byeong-Kyu; Ocon, Joey D.; Chan, Eng Seng

2017-01-01

Highlights: • NiO-hematite p-n junction photoanodes were fabricated via an in situ Ni-doping. • The fundamental mechanism of Ni"2"+ ions involved was elucidated. • The optimum Ni dopant was 25 M% for the highest photocurrent density. • It exhibited an excellent photoelectrochemical performance of 7-folds enhancement. - Abstract: Nanostructured nickel oxide-hematite (NiO/α-Fe_2O_3) p-n junction photoanodes synthesized from in situ doping of nickel (Ni) during cathodic electrodeposition of hematite were successfully demonstrated. A postulation model was proposed to explain the fundamental mechanism of Ni"2"+ ions involved, and the eventual formation of NiO on the subsurface region of hematite that enhanced the potential photoelectrochemical water oxidation process. Through this study, it was found that the measured photocurrent densities of the Ni-doped hematite photoanodes were highly dependent on the concentrations of Ni dopant used. The optimum Ni dopant at 25 M% demonstrated an excellent photoelectrochemical performance of 7-folds enhancement as compared to bare hematite photoanode. This was attributed to the increased electron donor density through the p-n junction and thus lowering the energetic barrier for water oxidation activity at the optimum Ni dopant concentration. Concurrently, the in situ Ni-doping of hematite has also lowered the photogenerated charge carrier transfer resistance as measured using the electrochemical impedance spectroscopy. It is expected that the fundamental understanding gained through this study is helpful for the rational design and construction of highly efficient photoanodes for application in photoelectrochemical process.

Three-Dimensional Bi-Continuous Nanoporous Gold/Nickel Foam Supported MnO2 for High Performance Supercapacitors.

Science.gov (United States)

Zhao, Jie; Zou, Xilai; Sun, Peng; Cui, Guofeng

2017-12-19

A three-dimensional bi-continuous nanoporous gold (NPG)/nickel foam is developed though the electrodeposition of a gold-tin alloy on Ni foam and subsequent chemical dealloying of tin. The newly-designed 3D metal structure is used to anchor MnO 2 nanosheets for high-performance supercapacitors. The formed ternary composite electrodes exhibit significantly-enhanced capacitance performance, rate capability, and excellent cycling stability. A specific capacitance of 442 Fg -1 is achieved at a scan rate of 5 mV s -1 and a relatively high mass loading of 865 μg cm -2 . After 2500 cycles, only a 1% decay is found at a scan rate of 50 mV s -1 . A high power density of 3513 W kg -1 and an energy density of 25.73 Wh kg -1 are realized for potential energy storage devices. The results demonstrate that the NPG/nickel foam hybrid structure significantly improves the dispersibility of MnO 2 and makes it promising for practical energy storage applications.

Contribution to the study of the electrodeposition of iron-nickel alloys; Contribution a l'etude du depot electrolytique des alliages fer-nickel

Energy Technology Data Exchange (ETDEWEB)

Valignat, J [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1967-12-01

Using a coulometric technique based upon the anodic intentiostatic dissolution, we studied the potentiostatic, deposition of nickel, iron and nickel iron alloys. We have shown that the minimum of the curve I = f (t) (deposition current versus time) is probably due to the transitory blocking of the surface by hydrogen and that the syn-crystallisation of nickel and iron is responsible for the anomalous co-deposition of these two elements. (author) [French] En employant une methode coulometrique par dissolution anodique intensipstatique, nous avons etudie le depot potentiostatique du nickel, du fer et des alliages fer-nickel. Nous avons pu montrer que le minimum de la courbe I = f (t) enregistree au cours du depot est du probablement au blocage momentane de la surface par l'hydrogene et que la syncristallisation du fer et du nickel est responsable de l'anomalie du depot simultane de ces deux elements. (auteur)

Recent Advances in Superhydrophobic Electrodeposits

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Jason Tam

2016-03-01

Full Text Available In this review, we present an extensive summary of research on superhydrophobic electrodeposits reported in the literature over the past decade. As a synthesis technique, electrodeposition is a simple and scalable process to produce non-wetting metal surfaces. There are three main categories of superhydrophobic surfaces made by electrodeposition: (i electrodeposits that are inherently non-wetting due to hierarchical roughness generated from the process; (ii electrodeposits with plated surface roughness that are further modified with low surface energy material; (iii composite electrodeposits with co-deposited inert and hydrophobic particles. A recently developed strategy to improve the durability during the application of superhydrophobic electrodeposits by controlling the microstructure of the metal matrix and the co-deposition of hydrophobic ceramic particles will also be addressed.

Incorporation of iridium into electrodeposited rhenium–nickel alloys

International Nuclear Information System (INIS)

Cohen Sagiv, Maayan; Eliaz, Noam; Gileadi, Eliezer

2013-01-01

Rhenium (Re), a refractory metal that has gained significant recognition as a high performance engineering material, is mostly used in military, aircraft and aerospace applications, as well as for catalysis in the petrochemical industry. However, its performance at high temperature in humid air is limited by the formation of rhenium heptoxide (Re 2 O 7 ), which penetrates the grain boundaries and causes brittleness. Improvement of this is being sought through the incorporation of iridium (Ir) into Re deposits. To this end, suitable plating baths for Re–Ir–Ni coatings were developed. These alloys were deposited from different aqueous solutions on copper substrates under galvanostatic conditions, in a three-electrode cell. The plating bath consisted of iridium tri-chloride, ammonium perrhenate and nickel sulfamate as the electroactive species, and citric acid as the complexing agent. The effects of bath composition and operating conditions on the Faradaic efficiency (FE), partial current densities, as well as on the thickness of the coatings and their composition were studied. Re–Ir–Ni coatings as thick as 18 μm, with Re-content as high as 73 at.% and Ir-content as high as 29 at.%, were obtained, using different plating baths. A mechanism of the electrochemical process was suggested. It was found that both an HCP Ir 0.4 Re 0.6 phase and an HCP Ni phase with nanometric crystallites were formed, possibly together with a hexagonal nickel hydride (Ni 2 H) phase

Electrodeposition of Zn-doped {alpha}-nickel hydroxide with flower-like nanostructure for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

You Zheng [Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China); Shen Kui; Wu Zhicheng [Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China); Wang Xiaofeng [Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China); Kong Xianghua, E-mail: kongxh@ustb.edu.cn [Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China)

2012-08-01

Zn-doped {alpha}-nickel hydroxide materials with flower-like nanostructures are synthesized by electrochemical deposition method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (SEM) and electrochemical measurements. XRD spectra indicate nickel hydroxide doped with Zn is {alpha}-Ni(OH){sub 2} with excellent crystallization. The SEM observation shows that the formation of Zn-doped Ni(OH){sub 2} includes two steps: a honeycomb-like film forms on the substrate first, then flower-like particles forms on the films. The nickel hydroxide doped with 5% Zn can maintain a maximum specific capacitance of 860 F g{sup -1}, suggesting its potential application in electrochemical capacitors.

Electrodeposition of Zn-doped α-nickel hydroxide with flower-like nanostructure for supercapacitors

Science.gov (United States)

You, Zheng; Shen, Kui; Wu, Zhicheng; Wang, Xiaofeng; Kong, Xianghua

2012-08-01

Zn-doped α-nickel hydroxide materials with flower-like nanostructures are synthesized by electrochemical deposition method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (SEM) and electrochemical measurements. XRD spectra indicate nickel hydroxide doped with Zn is α-Ni(OH)2 with excellent crystallization. The SEM observation shows that the formation of Zn-doped Ni(OH)2 includes two steps: a honeycomb-like film forms on the substrate first, then flower-like particles forms on the films. The nickel hydroxide doped with 5% Zn can maintain a maximum specific capacitance of 860 F g-1, suggesting its potential application in electrochemical capacitors.

Preparation of uranium electrodeposited target in aqueous system

International Nuclear Information System (INIS)

Chen Qiping; Li Yougen; Zhong Wenbin

2006-03-01

The main factors affecting uranium electrodeposition were tested and discussed. In the primary experiment about preparation of uranium isotopic target by electrodeposition, a stainless steel disk has been chosen as the target material, the electrolytic bath is comprised of UO 2 (NO 3 ) 2 and (NH 4 ) 2 C 2 O 4 , which has been adjusted to a pH of 2-3. Composition of the lost electrolytic bath was analysed by spectrophotometer. The thickness of resulting film is about 8-10 mg/cm 2 , the target having a thin, continuous, uniform layer of uranium, and its electrodeposited rate is more than 80%. (authors)

Electro-Deposition Laboratory

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Federal Laboratory Consortium — The electro-deposition laboratory can electro-deposit various coatings onto small test samples and bench level prototypes. This facility provides the foundation for...

Investigation into cathode polarization during deposition of rhodium-nickel and rhodium-indium alloys

International Nuclear Information System (INIS)

Evdokimova, N.V.; Byacheslavov, P.M.; Lokshtanova, O.G.

1979-01-01

The results of kinetic regularities experimental investigations during electrodeposition of rhodium-nickel and rhonium-indium alloys are presented. Methods of general and partial polarization curves have been used to show the nature of polarization during the rhonium-nickel and rhodium-indium alloys deposition. It is shown that indium into the rhodium-indium alloy and nickel into the rhodium-nickel alloy deposit with great depolarization ( PHIsub(In)sup(0)=-0.33B, PHIsub(Ni)sup(0)=-0.23B). Indium and nickel in pure form do not deposit from the electrolytes of the given composition (H 2 SO 4 - 50 g/l, HNH 2 SO 3 -10 g/l). The recalculation of partial polarization curve of indium precipitation into the rhodium-indium alloy in the mixed kinetics coordinates gives a straight line with 40 mV inclination angle. This corresponds to the delayed stage of the second electron addition with the imposition of diffusion limitations

Preparation of uranium electrodeposited target in aqueous system

Energy Technology Data Exchange (ETDEWEB)

Qiping, Chen; Yougen, Li; Wenbin, Zhong [China Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry

2006-03-15

The main factors affecting uranium electrodeposition were tested and discussed. In the primary experiment about preparation of uranium isotopic target by electrodeposition, a stainless steel disk has been chosen as the target material, the electrolytic bath is comprised of UO{sub 2}(NO{sub 3}){sub 2} and (NH{sub 4}){sub 2}C{sub 2}O{sub 4}, which has been adjusted to a pH of 2-3. Composition of the lost electrolytic bath was analysed by spectrophotometer. The thickness of resulting film is about 8-10 mg/cm{sup 2}, the target having a thin, continuous, uniform layer of uranium, and its electrodeposited rate is more than 80%. (authors)

Electrodeposition of zinc-nickel alloy from fluoborate baths - as a substitute for electrogalvanising

Energy Technology Data Exchange (ETDEWEB)

Ramesh Bapu, G.N.K.; Ayyapparaju, J.; Devaraj, G.

Use of fluoborate electroytes have been investigated for depositing a suitable composition of zinc-nickel alloy on mild steel for better corrosion protection. In the present investigation, the plating and bath conditions have been optimized so that zinc-nickel alloy coating from fluoborate solutions find applications for plating wires as well as other articles advantageously in the place of zinc coatings.

Effects of choline chloride on electrodeposited Ni coating from a Watts-type bath

Energy Technology Data Exchange (ETDEWEB)

Wang, Yurong; Yang, Caihong; He, Jiawei; Wang, Wenchang [School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Mitsuzak, Naotoshi [Qualtec Co., Ltd, Osaka 590-0906 (Japan); Chen, Zhidong, E-mail: zdchen.lab@gmail.com [School of Material Science and Engineering, Jiangsu Key Laboratory of Materials, Surface and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Advanced Catalytic Material and Technology, Changzhou University, Changzhou 213164 (China)

2016-05-30

Graphical abstract: - Highlights: • ChCl was applied as additive and conducting salt in Watts-type bath. • Progressive addition of ChCl leads to the crystal orientation (1 1 1) predominant. • The grain size and microhardness were refined and enhanced by increasing ChCl. • ChCl could be a good alternative to NiCl{sub 2} and additives for bright Ni electroplating. - Abstract: Electrodeposition of bright nickel (Ni) was carried out in a Watts-type bath. Choline chloride (ChCl) was applied as a multifunctional additive and substitute for nickel chloride (NiCl{sub 2}) in a Watts-type bath. The function of ChCl was investigated through conductivity tests, anodic polarization, and cathodic polarization experiments. The studies revealed that ChCl performed well as a conducting salt, anodic activator, and cathodic inhibitor. The effects of ChCl on deposition rate, preferred orientation, grain size, surface morphology, and microhardness of Ni coatings were also studied. The deposition rate reached a maximum value of greater than 27 μm h{sup −1} when 20 g L{sup −1} ChCl was introduced to the bath. Using X-ray diffraction, it was confirmed that progressive addition of ChCl promoted the preferred crystal orientation modification from (2 0 0) and (2 2 0) to (1 1 1), refined grain size, and enhanced microhardness. The presence of ChCl lowered the roughness of the coating.

Electrodeposited Ni nanowires-track etched P.E.T. composites as selective solar absorbers

Science.gov (United States)

Lukhwa, R.; Sone, B.; Kotsedi, L.; Madjoe, R.; Maaza, M.

2018-05-01

This contribution reports on the structural, optical and morphological properties of nanostructured flexible solar-thermal selective absorber composites for low temperature applications. The candidate material in the system is consisting of electrodeposited nickel nano-cylinders embedded in track-etched polyethylene terephthalate (PET) host membrane of pore sizes ranging between 0.3-0.8µm supported by conductive nickel thin film of about 0.5µm. PET were irradiated with 11MeV/u high charged xenon (Xe) ions at normal incidence. The tubular and metallic structure of the nickel nano-cylinders within the insulator polymeric host forms a typical ceramic-metal nano-composite "Cermet". The produced material was characterized by the following techniques: X-ray diffraction (XRD) for structural characterization to determine preferred crystallographic structure, and grain size of the materials; Scanning electron microscopy (SEM) to determine surface morphology, particle size, and visual imaging of distribution of structures on the surface of the substrate; Atomic force microscopy (AFM) to characterize surface roughness, surface morphology, and film thickness, and UV-Vis-NIR spectrophotometer to measure the reflectance, then to determine solar absorption

Controlled electroplating and electromigration in nickel electrodes for nanogap formation

Energy Technology Data Exchange (ETDEWEB)

De Los Santos Valladares, Luis; Mitrelias, Thanos; Sfigakis, Francois; Barnes, Crispin H W [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Leon Felix, Lizbet; Bustamante Dominguez, Angel [Laboratorio de Ceramicos y Nanomateriales, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Khondaker, Saiful I [NanoScience Technology Center and Department of Physics, University of Central Florida, Orlando, FL 32826 (United States); Majima, Yutaka, E-mail: ld301@cam.ac.uk, E-mail: luisitodv@yahoo.es [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

2010-11-05

We report the fabrication of nickel nanospaced electrodes by electroplating and electromigration for nanoelectronic devices. Using a conventional electrochemical cell, nanogaps can be obtained by controlling the plating time alone and after a careful optimization of electrodeposition parameters such as electrolyte bath, applied potential, cleaning, etc. During the process, the gap width decreases exponentially with time until the electrode gaps are completely bridged. Once the bridge is formed, the ex situ electromigration technique can reopen the nanogap. When the gap is {approx} 1 nm, tunneling current-voltage characterization shows asymmetry which can be corrected by an external magnetic field. This suggests that charge transfer in the nickel electrodes depends on the orientation of magnetic moments.

Controlled electroplating and electromigration in nickel electrodes for nanogap formation

International Nuclear Information System (INIS)

De Los Santos Valladares, Luis; Mitrelias, Thanos; Sfigakis, Francois; Barnes, Crispin H W; Leon Felix, Lizbet; Bustamante Dominguez, Angel; Khondaker, Saiful I; Majima, Yutaka

2010-01-01

We report the fabrication of nickel nanospaced electrodes by electroplating and electromigration for nanoelectronic devices. Using a conventional electrochemical cell, nanogaps can be obtained by controlling the plating time alone and after a careful optimization of electrodeposition parameters such as electrolyte bath, applied potential, cleaning, etc. During the process, the gap width decreases exponentially with time until the electrode gaps are completely bridged. Once the bridge is formed, the ex situ electromigration technique can reopen the nanogap. When the gap is ∼ 1 nm, tunneling current-voltage characterization shows asymmetry which can be corrected by an external magnetic field. This suggests that charge transfer in the nickel electrodes depends on the orientation of magnetic moments.

Physical and chemical evaluation of the effect of a magnetic field on the electrodeposition of Ni in low carbon steel

International Nuclear Information System (INIS)

Campo G, G. A.

2015-01-01

In this study nickel coatings were obtained, with and without the presence of magnetic field at 60 degrees Celsius for 7, 12 and 17 minutes on substrates of AISI 1018 carbon steel, from a classical type Watts solution. The properties of the coatings were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy, hardness tester and roughness tester, the electrochemical behavior of the films was also studied through RP and EIE and also capacitance calculations, corrosion rate and thickness were made. In general, the magnetic field has a negative influence on the physical and chemical properties of an electrodeposited Ni steel AISI 1018. The details are discussed in this research. (Author)

Magnetic properties of nickel nanostructures grown in AAO membrane

International Nuclear Information System (INIS)

Oh, S.-L.; Kim, Y.-R.; Malkinski, L.; Vovk, A.; Whittenburg, S.L.; Kim, E.-M.; Jung, J.-S.

2007-01-01

One-dimensional nanostructures can be built by performing chemical or electrochemical reactions in the pores of a suitable host or matrix material. We have developed a method of electrodeposition of nickel nanostructures inside cylindrical pores of the anodic aluminum oxide (AAO) membranes, which provides precise control of the nanostructure height. We were able to fabricate hexagonal arrays of particles in the form of spheres, rods and long wires. Magnetization measurements of these nanostructures as function of field and temperature were carried out using a superconducting quantum-interference device magnetometer. The shape of nickel nanostructures has been investigated by field emission scanning electron microscope. The coercivity of the nickel nanostructures measured with the field perpendicular to the membrane was increasing with increasing aspect ratio of the nanostructures. These experimental values of the coercivity, varying from 200 Oe for the spherical nanodots to 730 Oe for the nanowires, are in a fair agreement with our micromagnetic modeling calculations

Magnetic properties of nickel nanostructures grown in AAO membrane

Energy Technology Data Exchange (ETDEWEB)

Oh, S -L [Department of Chemistry, Yonsei University, Seoul (Korea, Republic of); Kim, Y -R [Department of Chemistry, Yonsei University, Seoul (Korea, Republic of); Malkinski, L [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Vovk, A [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Whittenburg, S L [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Kim, E -M [Korea Basic Science Institute, Kangnung 210-702 (Korea, Republic of); Jung, J -S [Department of Chemistry, Kangnung National University, Kangnung 210-702 (Korea, Republic of)

2007-03-15

One-dimensional nanostructures can be built by performing chemical or electrochemical reactions in the pores of a suitable host or matrix material. We have developed a method of electrodeposition of nickel nanostructures inside cylindrical pores of the anodic aluminum oxide (AAO) membranes, which provides precise control of the nanostructure height. We were able to fabricate hexagonal arrays of particles in the form of spheres, rods and long wires. Magnetization measurements of these nanostructures as function of field and temperature were carried out using a superconducting quantum-interference device magnetometer. The shape of nickel nanostructures has been investigated by field emission scanning electron microscope. The coercivity of the nickel nanostructures measured with the field perpendicular to the membrane was increasing with increasing aspect ratio of the nanostructures. These experimental values of the coercivity, varying from 200 Oe for the spherical nanodots to 730 Oe for the nanowires, are in a fair agreement with our micromagnetic modeling calculations.

Microscopic and magnetic properties of template assisted electrodeposited iron nanowires

Energy Technology Data Exchange (ETDEWEB)

Irshad, M. I., E-mail: imrancssp@gmail.com; Mohamed, N. M., E-mail: noranimuti-mohamed@petronas.com.my; Yar, A., E-mail: asfandyarhargan@gmail.com [Department of Fundamental & Applied Sciences, Universiti Teknologi PETRONAS, 31750 PERAK (Malaysia); Ahmad, F., E-mail: faizahmad@petronas.com.my; Abdullah, M. Z., E-mail: zaki-abdullah@petronas.com.my [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, 31750 PERAK (Malaysia)

2015-07-22

Nanowires of magnetic materials such as Iron, nickel, cobalt, and alloys of them are one of the most widely investigated structures because of their possible applications in high density magnetic recording media, sensor elements, and building blocks in biological transport systems. In this work, Iron nanowires have been prepared by electrodeposition technique using Anodized Aluminium Oxide (AAO) templates. The electrolyte used consisted of FeSO{sub 4.}6H{sub 2}O buffered with H{sub 3}BO{sub 3} and acidized by dilute H{sub 2}SO{sub 4}. FESEM analysis shows that the asdeposited nanowires are parallel to one another and have high aspect ratio with a reasonably high pore-filing factor. To fabricate the working electrode, a thin film of copper (∼ 220 nm thick) was coated on back side of AAO template by e-beam evaporation system to create electrical contact with the external circuit. The TEM results show that electrodeposited nanowires have diameter around 100 nm and are polycrystalline in structure. Magnetic properties show the existence of anisotropy for in and out of plane configuration. These nanowires have potential applications in magnetic data storage, catalysis and magnetic sensor applications.

Nickel hydroxide modified electrodes for urea determination

Directory of Open Access Journals (Sweden)

Luiz Henrique Dall´Antonia

2007-03-01

Full Text Available Nickel hydroxide films were prepared by electrodeposition from a solution Ni(NO32 0,05 mol L ?¹ on ITO electrodes (Tin oxide doped with Indium on PET-like plastic film, applying a current of - 0,1 A cm ?² during different time intervals between 1800 and 7200 s. The electrochemical behavior of the nickel hydroxide electrode was investigated through a cyclic voltammogram, in NaOH 1,0 mol L ?¹, where it was observed two peaks in the profile in 0,410 and 0,280 V, corresponding to redox couple Ni(II/Ni(III. A sensor for urea presenting a satisfactory answer can be obtained when, after the deposit of the film of Ni(OH2 on the electrode of nickel, it is immersed in a solution of NaOH 1,0 mol L ?¹ and applying a potential of + 0,435 V, where the maximum of the anodic current occurs in the cyclic voltammogram. Analyzing the results it can be observed that, for a range of analite concentration between 5 to 50 m mol L ?¹, the behavior is linear and the sensibility found was of 20,3 mA cm?² (mol L?¹?¹, presenting reproducibility confirming the nickel hydroxide electrodes utilization for the determination of urea.

Electrodeposition of Nickel Nanoparticles for the Alkaline Hydrogen Evolution Reaction: Correlating Electrocatalytic Behavior and Chemical Composition.

Science.gov (United States)

Tao, Shasha; Yang, Florent; Schuch, Jona; Jaegermann, Wolfram; Kaiser, Bernhard

2018-03-09

Ni nanoparticles (NPs) consisting of Ni, NiO, and Ni(OH) 2 were formed on Ti substrates by electrodeposition as electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. Additionally, the deposition parameters including the potential range and the scan rate were varied, and the resulting NPs were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. The chemical composition of the NPs changed upon using different conditions, and it was found that the catalytic activity increased with an increase in the amount of NiO. From these data, optimized NPs were synthesized; the best sample showed an onset potential of approximately 0 V and an overpotential of 197 mV at a cathodic current density of 10 mA cm -2 as well as a small Tafel slope of 88 mV dec -1 in 1 m KOH, values that are comparable to those of Pt foil. These NPs consist of approximately 25 % Ni and Ni(OH) 2 each, as well as approximately 50 % NiO. This implies that to obtain a successful HER electrocatalyst, active sites with differing compositions have to be close to each other to promote the different reaction steps. Long-time measurements (30 h) showed almost complete transformation of the highly active catalyst compound consisting of Ni 0 , NiO, and Ni(OH) 2 into the less active Ni(OH) 2 phase. Nevertheless, the here-employed electrodeposition of nonprecious metal/metal-oxide combination compounds represents a promising alternative to Pt-based electrocatalysts for water reduction to hydrogen. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposition of Iridium Oxide by Cyclic Voltammetry: Application of Response Surface Methodology

Directory of Open Access Journals (Sweden)

Kakooei Saeid

2014-07-01

Full Text Available The effects of scan rate, temperature, and number of cycles on the coating thickness of IrOX electrodeposited on a stainless steel substrate by cyclic voltammetry were investigated in a statistical system. The central composite design, combined with response surface methodology, was used to study condition of electrodeposition. All fabricated electrodes were characterized using electrochemical methods. Field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy were performed for IrOX film characterization. Results showed that scan rate significantly affects the thickness of the electrodeposited layer. Also, the number of cycles has a greater effect than temperature on the IrOX thickness.

High emittance black nickel coating on copper substrate for space applications

Energy Technology Data Exchange (ETDEWEB)

Somasundaram, Soniya, E-mail: jrf0013@isac.gov.in; Pillai, Anju M., E-mail: anjum@isac.gov.in; Rajendra, A., E-mail: rajendra@isac.gov.in; Sharma, A.K., E-mail: aks@isac.gov.in

2015-09-15

Highlights: • High emittance black nickel coating is obtained on copper substrate. • The effect of various process parameters on IR emittance is studied systematically. • Process parameters are optimized to develop a high emittance black nickel coating. • Coating obtained using the finalized parameters exhibited an emittance of 0.83. • SEM and EDAX are used for coating characterization. - Abstract: Black nickel, an alloy coating of zinc and nickel, is obtained on copper substrate by pulse electrodeposition from a modified Fishlock bath containing nickel sulphate, nickel ammonium sulphate, zinc sulphate and ammonium thiocyanate. A nickel undercoat of 4–5 μm thickness is obtained using Watts bath to increase the corrosion resistance and adhesion of the black nickel coating. The effect of bath composition, temperature, solution pH, current density and plating time on the coating appearance and corresponding infra-red emittance of the coating is investigated systematically. Process parameters are optimized to develop a high emittance space worthy black nickel coating to improve the heat radiation characteristics. The effect of the chemistry of the plating bath on the coating composition was studied using energy dispersive X-ray analysis (EDAX) of the coatings. The 5–6 μm thick uniform jet black zinc–nickel alloy coating obtained with optimized process exhibited an emittance of 0.83 and an absorbance of 0.92. The zinc to nickel ratio of black nickel coatings showing high emittance and appealing appearance was found to be in the range 2.3–2.4.

Cyclic Voltammetric Study of High Speed Silver Electrodeposition and Dissolution in Low Cyanide Solutions

Directory of Open Access Journals (Sweden)

Bo Zheng

2016-01-01

Full Text Available The electrochemical processes in solutions with a much lower amount of free cyanide (<10 g/L KCN than the conventional alkaline silver electrolytes were first explored by using cyclic voltammetry. The electrochemical behavior and the effect of KAg(CN2, KCN, and KNO3 electrolytes and solution pH on the electrodeposition and dissolution processes were investigated. Moreover, suitable working conditions for high speed, low cyanide silver electrodeposition were also proposed. Both silver and cyanide ions concentration had significant effects on the electrode polarization and deposition rate. The onset potential of silver electrodeposition could be shifted to more positive values by using solutions containing higher silver and lower KCN concentration. Higher silver concentration also led to higher deposition rate. Besides maintaining high conductivity of the solution, KNO3 might help reduce the operating current density required for silver electrodeposition at high silver concentration albeit at the expense of slowing down the electrodeposition rate. The silver dissolution consists of a limiting step and the reaction rate depends on the amount of free cyanide ions. The surface and material characteristics of Ag films deposited by low cyanide solution are also compared with those deposited by conventional high cyanide solution.

Molybdenum carbide coating electrodeposited from molten fluoride bath

International Nuclear Information System (INIS)

Topor, D.C.; Selman, J.R.

1987-01-01

Molybdenum carbide has been recently considered as a candidate material for the protection of common steel-based substrates in high-temperature high-sulfur activity applications. Methods to produce coatings of materials such as Mo/sub 2/C are scarce and only the electrodeposition from molten salts can yield dense, pore-free layers on various metallic profiles. Recently Stern reported the deposition of a Mo/sub 2/C coating on nickel substrate form, FLINAK + K/sub 2/MoCl/sub 6/ + Na/sub 2/CO/sub 3/ mixture at 850 0 C. Electrodeposition of Mo/sub 2/C on a cathode surface proceeds according to a rather complicated mechanism which may involve simultaneous reduction of carbonate to C, of molybdate to Mo and a subsequent chemical reaction between both species. The deposit grows further as a coherent coating. Reduction of CO/sub 2/ or carbonate to carbon in a fused salt medium could follow different paths but Li/sup +/ ions or other highly polarizing ions must be present. A similar situation in which a polyatomic anion discharges at the cathode is encountered when molybdates are used as source of molybdenum. In fluoride melts the chemistry of Mo(VI) species is considered to be much simpler due to the hard fluoride ions. These ions form strong complexes with molybdenum and the resulting solution is more stable

Neutron reflectivity of electrodeposited thin magnetic films

International Nuclear Information System (INIS)

Cooper, Joshaniel F.K.; Vyas, Kunal N.; Steinke, Nina-J.; Love, David M.; Kinane, Christian J.; Barnes, Crispin H.W.

2014-01-01

Highlights: • Electrodeposited magnetic bi-layers were measured by polarised neutron reflectivity. • When growing a CoNiCu alloy from a single bath a Cu rich region is initially formed. • This Cu rich region is formed in the first layer but not subsequent ones. • Ni deposition is inhibited in thin film growth and Co deposits anomalously. • Alloy magnetism and neutron scattering length give a self-consistent model. - Abstract: We present a polarised neutron reflectivity (PNR) study of magnetic/non-magnetic (CoNiCu/Cu) thin films grown by single bath electrodeposition. We find that the composition is neither homogeneous with time, nor consistent with bulk values. Instead an initial, non-magnetic copper rich layer is formed, around 2 nm thick. This layer is formed by the deposition of the dilute, but rapidly diffusing, Cu 2+ ions near the electrode surface at the start of growth, before the region is depleted and the deposition becomes mass transport limited. After the region has been depleted, by growth etc., this layer does not form and thus may be prevented by growing a copper buffer layer immediately preceding the magnetic layer growth. As has been previously found, cobalt deposits anomalously compared to nickel, and even inhibits Ni deposition in thin films. The layer magnetisation and average neutron scattering length are fitted independently but both depend upon the alloy composition. Thus these parameters can be used to check for model self-consistency, increasing confidence in the derived composition

Electrodepositing of Au on hollow PS micro-spheres

International Nuclear Information System (INIS)

Sun Jingyuan; Zhang Yunwang; Du Kai; Wan Xiaobo; Xiao Jiang; Zhang Wei; Zhang Lin; Chen Jing

2010-01-01

Using the self-regulating new micro-sphere electrodepositing device, the techniques of electrodepositing gold on hollow PS micro-spheres were established. The experiment was carried out under the following conditions: voltage was about 0.7 ∼ 0.8 V, current density was 2.0 mA · cm -2 , the temperature was 45 degree C, cathode rotating rate was 250 r · min -1 , flow rate of the solution was 7 mL · min -1 · cm -2 . Hollow gold-plated micro-spheres were prepared with well spherical symmetry, uniform thickness and surface smoothness under 500 nm. The speed of the gold depositing was 6 μm · h -1 . (authors)

Does airborne nickel exposure induce nickel sensitization?

Science.gov (United States)

Mann, Eugen; Ranft, Ulrich; Eberwein, Georg; Gladtke, Dieter; Sugiri, Dorothee; Behrendt, Heidrun; Ring, Johannes; Schäfer, Torsten; Begerow, Jutta; Wittsiepe, Jürgen; Krämer, Ursula; Wilhelm, Michael

2010-06-01

Nickel is one of the most prevalent causes of contact allergy in the general population. This study focuses on human exposure to airborne nickel and its potential to induce allergic sensitization. The study group consisted of 309 children at school-starter age living in the West of Germany in the vicinity of two industrial sources and in a rural town without nearby point sources of nickel. An exposure assessment of nickel in ambient air was available for children in the Ruhr district using routinely monitored ambient air quality data and dispersion modelling. Internal nickel exposure was assessed by nickel concentrations in morning urine samples of the children. The observed nickel sensitization prevalence rates varied between 12.6% and 30.7%. Statistically significant associations were showed between exposure to nickel in ambient air and urinary nickel concentration as well as between urinary nickel concentration and nickel sensitization. Furthermore, an elevated prevalence of nickel sensitization was associated with exposure to increased nickel concentrations in ambient air. The observed associations support the assumption that inhaled nickel in ambient air might be a risk factor for nickel sensitization; further studies in larger collectives are necessary.

Improved mechanical and corrosion properties of nickel composite coatings by incorporation of layered silicates

Energy Technology Data Exchange (ETDEWEB)

Tientong, J. [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States); Ahmad, Y.H. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Nar, M.; D' Souza, N. [University of North Texas, Department of Mechanical and Energy Engineering, Denton, TX 76207 (United States); Mohamed, A.M.A. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Golden, T.D., E-mail: tgolden@unt.edu [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States)

2014-05-01

Layered silicates as exfoliated montmorillonite are incorporated into nickel films by electrodeposition, enhancing both corrosion resistance and hardness. Films were deposited onto stainless steel from a plating solution adjusted to pH 9 containing nickel sulfate, sodium citrate, and various concentrations of exfoliated montmorillonite. The presence of the incorporated layered silicate was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The composite films were also compact and smooth like the pure nickel films deposited under the same conditions as shown by scanning electron microscopy. X-ray diffraction results showed that incorporation of layered silicates into the film do not affect the nickel crystalline fcc structure. The nanocomposite films exhibited improved stability and adhesion. Pure nickel films cracked and peeled from the substrate when immersed in 3.5% NaCl solution within 5 days, while the nanocomposite films remained attached even after 25 days. The corrosion resistance of the nickel nanocomposites was also improved compared to nickel films. Nickel-layered silicate composites showed a 25% increase in Young's modulus and a 20% increase in hardness over pure nickel films. - Highlights: • 0.05–2% of layered silicates are incorporated into crystalline nickel films. • Resulting composite films had improved stability and adhesion. • Corrosion resistance improved for the composite films. • Hardness improved 20% and young's modulus improved 25% for the composite films.

The preparation and thermoelectric properties of molten salt electrodeposited boron wafers

International Nuclear Information System (INIS)

Kumashiro, Y.; Ozaki, S.; Sato, K.; Kataoka, Y.; Hirata, K.; Yokoyama, T.; Nagatani, S.; Kajiyama, K.

2004-01-01

We have prepared electrodeposited boron wafer by molten salts with KBF 4 -KF at 680 deg. C using graphite crucible for anode and silicon wafer and nickel plate for cathodes. Experiments were performed by various molar ratios KBF 4 /KF and current densities. Amorphous p-type boron wafers with purity 87% was deposited on nickel plate for 1 h. Thermal diffusivity by ring-flash method and heat capacity by DSC method produced thermal conductivity showing amorphous behavior in the entire temperature range. The systematical results on thermoelectric properties were obtained for the wafers prepared with KBF 4 -KF (66-34 mol%) under various current densities in the range 1-2 A/cm 2 . The temperature dependencies of electrical conductivity showed thermal activated type with activation energy of 0.5 eV. Thermoelectric power tended to increase with increasing temperature up to high temperatures with high values of (1-10) mV/K. Thermoelectric figure-of-merit was 10 -4 /K at high temperatures. Estimated efficiency of thermoelectric energy conversion would be calculated to be 4-5%

Electrodeposited Porous Mn1.5Co1.5O₄/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors.

Science.gov (United States)

Pan, Guan-Ting; Chong, Siewhui; Yang, Thomas C-K; Huang, Chao-Ming

2017-03-31

Mesoporous Mn 1.5 Co 1.5 O₄ (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO₃) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg -1 and a power density of 1.01 kW·kg -1 at 1 A·g -1 . After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling.

Electrodeposited tungsten-nickel-boron: A replacement for hexavalent chromium

International Nuclear Information System (INIS)

Steffani, C.; Meltzer, M.

1995-04-01

Chromium, deposited from acidic solutions of its hexavalent ion, has been the rule for wear resistant, corrosion resistant coatings for many years. Although chromium coatings are durable, the plating process generates air emissions, effluent rinse waters, and process solutions that are toxic, suspected carcinogens, and a risk to human health and the environment. Tungsten-nickel-boron (W-Ni-B) alloy deposition is a potential substitute for hexavalent chrome. It has excellent wear, corrosion, and mechanical properties and also may be less of an environmental risk. This study examines the electroplating process and deposit properties of W-Ni-B and compares them with those of hexavalent chrome

Electrocatalysis of the hydrogen evolution reaction by rhenium oxides electrodeposited by pulsed-current

International Nuclear Information System (INIS)

Vargas-Uscategui, Alejandro; Mosquera, Edgar; Chornik, Boris; Cifuentes, Luis

2015-01-01

Highlights: • Rhenium oxides were produced by means of pulsed current electrodeposition over ITO. • The electrocatalytic behavior of rhenium oxides electrodeposited over ITO was studied. • Electrodeposited rhenium oxides showed electrocatalytic behavior increasing the rate of the hydrogen evolution reaction. • The electrocatalysis behavior was explained considering the relative abundance of Re species on the surface of the electrodeposited material. - Abstract: Rhenium oxides are materials of interest for applications in the catalysis of reactions such as those occurring in fuel cells and photoelectrochemical cells. This research work was devoted to the production of rhenium oxide by means of pulsed current electrodeposition for the electrocatalysis of the hydrogen evolution reaction (HER). Rhenium oxides were electrodeposited over a transparent conductive oxide substrate (Indium Tin-doped Oxide – ITO) in an alkaline aqueous electrolyte. The electrodeposition process allowed the production of rhenium oxides islands (200–600 nm) with the presence of three oxidized rhenium species: Re"I"V associated to ReO_2, Re"V"I associated to ReO_3 and Re"V"I"I associated to H(ReO_4)H_2O. Electrodeposited rhenium oxides showed electrocatalytic behavior over the HER and an increase of one order of magnitude of the exchange current density was observed compared to the reaction taking place on the bare substrate. The electrocatalytic behavior varied with the morphology and relative abundance of oxidized rhenium species in the electrodeposits. Finally, two mechanisms of electrocatalysis were proposed to explain experimental results.

Electrodeposited Porous Mn1.5Co1.5O4/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors

Directory of Open Access Journals (Sweden)

Guan-Ting Pan

2017-03-01

Full Text Available Mesoporous Mn1.5Co1.5O4 (MCO spinel films were prepared directly on a conductive nickel (Ni foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni-15 min electrode (electrodeposition time: 15 min exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively. Further, an asymmetric supercapacitor that utilizes (MCO/Ni-15 min as a positive electrode, a plasma-treated activated carbon (PAC/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO3 gel electrolyte (denoted as (PAC/Ni//(MCO/Ni-15 min was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg−1 and a power density of 1.01 kW·kg−1 at 1 A·g−1. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni//(MCO/Ni-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling.

Electrodeposited Porous Mn1.5Co1.5O4/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors

Science.gov (United States)

Pan, Guan-Ting; Chong, Siewhui; Yang, Thomas C.-K.; Huang, Chao-Ming

2017-01-01

Mesoporous Mn1.5Co1.5O4 (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO3) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg−1 and a power density of 1.01 kW·kg−1 at 1 A·g−1. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling. PMID:28772727

The synthesis of a new kind of magnetic coating on carbon fibers by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Wang Rui; Wan Yizao; He Fang; Qi Yu; You Wei [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Luo Honglin, E-mail: hlluo64@yahoo.com [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

2012-01-15

Nickel/Fe{sub 3}O{sub 4} nanoparticle (Ni/Fe{sub 3}O{sub 4}-NPs) composite coatings on the surface of carbon fiber were prepared by electrodeposition in a nickel-plating bath containing Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}-NPs). The composite of carbon fiber with nanocomposite coatings were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) analysis, thermogravimetric (TG) analysis and vibrating sample magnetometer (VSM). The microstructure observation reveals that the Fe{sub 3}O{sub 4}-NPs distribute uniformly in the coatings. TG and VSM analysis show that the carbon fibers with Ni/Fe{sub 3}O{sub 4}-NPs composite coatings exhibit higher thermal stability and saturation magnetization than carbon fiber with Ni coatings. The result is attributed to the homogeneous distribution of magnetic Fe{sub 3}O{sub 4} in the composite coatings.

Nickel group cluster anion reactions with carbon monoxide: Rate coefficients and chemisorption efficiency

Science.gov (United States)

Hintz, Paul A.; Ervin, Kent M.

1994-04-01

Reactions of Ni-n(n=3-10), Pd-n(n=3-8), and Pt-n(n=3-7) with CO are studied in a flow tube reactor. Bimolecular rate coefficients are measured for the association reaction of CO adsorbing on the cluster surface. The rate coefficients range from about 10% of the collision rate for the trimer anions to near the collision rate for clusters larger than four atoms. The maximum number of CO molecules that bind to each cluster is determined. Whereas the saturation limits for nickel are typical for an 18 electron transition metal, the limits for platinum are lower, reflecting the electron deficient structures observed in condensed phase chemistry. The CO saturated palladium clusters represent the first examples of saturated binary palladium carbonyl compounds. Comparisons are made to similar studies on metal cation and neutral clusters and also to surface scattering studies of nickel group metals.

The chemistry and structure of nickel–tungsten coatings obtained by pulse galvanostatic electrodeposition

International Nuclear Information System (INIS)

Argañaraz, M.P. Quiroga; Ribotta, S.B.; Folquer, M.E.; Zelaya, E.; Llorente, C.; Ramallo-López, J.M.; Benítez, G.; Rubert, A.; Gassa, L.M.; Vela, M.E.; Salvarezza, R.C.

2012-01-01

A detailed characterization of electrodeposited Ni-W coatings prepared by pulse electrodeposition on steel and copper substrates is presented. The coatings were obtained at high current pulse frequency and show high microhardness and absence of brittleness. The surface of the coating consists of nanometer sized crystals forming a cauliflower-like structure protected by a mixture of nickel and tungsten oxides. The cauliflower structure is preserved into the bulk coating that exhibits an average composition ≈70 at% Ni-30 at% W. Different phases are observed in the bulk structure: a W-rich amorphous phase (≈40%) and Ni-rich crystalline phases (≈60%). The crystalline phases consist of crystalline domains ≈7 nm in size of Ni(W) (fcc) solid solution (12 at% W content) and a minor Ni 4 W component (less than 10%). The amorphous phase exhibits a less compact Ni-W structure where some amount of C could also be present. Oxidized W species cannot be detected in the bulk coating, thus discarding the presence of significant amounts of tungsten carbide, tungstates or citrate–tungsten complexes. Our results shed light on controversial points related to the chemical composition and demonstrate the complex structure of this system.

Studying the initial stages of film electrodeposition of magnetic cobalt-tungsten alloys

International Nuclear Information System (INIS)

Rachinskas, V.S.; Orlovskaya, L.V.; Parfenov, V.A.; Yasulajtene, V.V.

1996-01-01

Initial stages of magnetic film electrodeposition by recording potentiodynamic polarization and j c ,t-curves, determination of surface structure of electrolytically deposited films by the method of XPS and study of thin coating properties have been considered. It is shown that at initial stage of electrodeposition of magnetic Co-W-films a sharp decrease in cathode process rate and formation of Co(OH) 2 , WO 3 and/or WO 4 2- occur on Cu-cathode surface. Electrodeposition of metallic magnetic Co-W-alloy, consisting of Co, W and containing basic compounds of co-deposited metals, takes place after a certain time period depending on deposition E c . 6 refs.; 3 figs

An efficient route for catalytic activity promotion via hybrid electro-depositional modification on commercial nickel foam for hydrogen evolution reaction in alkaline water electrolysis

Energy Technology Data Exchange (ETDEWEB)

Ma, Guanshui; He, Yongwei; Wang, Mei; Zhu, Fuchun; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Yingze West Road 79, Taiyuan 030024 (China); Wang, Xiaoguang, E-mail: wangxiaog1982@163.com [Research Institute of Surface Engineering, Taiyuan University of Technology, Yingze West Road 79, Taiyuan 030024 (China); International Iberian Nanotechnology Laboratory (INL), 4715-330 Braga (Portugal)

2014-09-15

Highlights: • Mono-Cu surface modification depress the HER activity of Ni-foam. • Hybrid Ni-foam/Cu0.01/Co0.05 exhibits superior HER performance. • Layer-by-layer structure may contribute to a synergistic promoting effect. - Abstract: In this paper, the single- and hybrid-layered Cu, Ni and Co thin films were electrochemically deposited onto the three-dimensional nickel foam as composite cathode catalyst for hydrogen evolution reaction in alkaline water electrolysis. The morphology, structure and chemical composition of the electrodeposited composite catalysts were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Electrochemical measurement depicted that, for the case of the monometallic layered samples, the general activity for hydrogen evolution reaction followed the sequence: Ni-foam/Ni > Ni-foam/Co > bare Ni-foam > Ni-foam/Cu. It is noteworthy that, the hybrid-layered Ni-foam/Cu0.01/Co0.05 exhibited the highest catalytic activity towards hydrogen evolution reaction with the current density as high as 2.82 times that of the bare Ni-foam. Moreover, both excellent electrochemical and physical stabilities can also be acquired on the Ni-foam/Cu0.01/Co0.05, making this hybrid-layered composite structure as a promising HER electro-catalyst.

Surface-Enhanced Infrared Absorption of o-Nitroaniline on Nickel Nanoparticles Synthesized by Electrochemical Deposition

Directory of Open Access Journals (Sweden)

Yufang Niu

2014-01-01

Full Text Available Nickel nanoparticles were electrochemically deposited on indium-tin oxide (ITO coated glass plate in a modified Watt’s electrolyte. The surface-enhanced infrared absorption (SEIRA effect of the nanoparticles was evaluated by attenuated total reflection spectroscopy (ATR-FTIR using o-nitroaniline as a probe molecule. Electrodeposition parameters such as deposition time, pH value, and the type of surfactants were investigated. The morphology and the microstructure of the deposits were characterized by the field emission scanning electron microscope (FESEM and the atomic force microscope (AFM, respectively. The results indicate that the optimum parameters were potential of 1.3 V, time of 30 s, and pH of 8.92 in the solution of 0.3756 mol/L diethanolamine, 0.1 mol/L nickel sulfate, 0.01 mol/L nickel chloride, and 0.05 mol/L boric acid. The FESEM observation shows that the morphology of nickel nanoparticles with best enhancement effect is spherical and narrowly distributed particles with the average size of 50 nm. SEIRA enhancement factor is about 68.

Electrodeposited binder-free NiCo2O4@carbon nanofiber as a high performance anode for lithium ion batteries

Science.gov (United States)

Zhang, Jie; Chu, Ruixia; Chen, Yanli; Jiang, Heng; Zhang, Ying; Huang, Nay Ming; Guo, Hang

2018-03-01

Binder-free nickel cobaltite on a carbon nanofiber (NiCo2O4@CNF) anode for lithium ion batteries was prepared via a two-step procedure of electrospinning and electrodeposition. The CNF was obtained by annealing electrospun poly-acrylonitrile (PAN) in nitrogen (N2). The NiCo2O4 nanostructures were then grown on the CNF by electrodeposition, followed by annealing in air. Experimental results showed that vertically aligned NiCo2O4 nanosheets had uniformly grown on the surface of the CNF, forming an interconnected network. The NiCo2O4@CNF possessed considerable lithium storage capacity and cycling stability. It exhibited a high reversible capacity of 778 mAhg-1 after 300 cycles at a current density of 0.25 C (1 C = 890 mAg-1) with an average capacity loss rate of 0.05% per cycle. The NiCo2O4@CNF had considerable rate capacities, delivering a capacity of 350 mAhg-1 at a current density of 2.0 C. The outstanding electrochemical performance can be mainly attributed to the following: (1) The nanoscale structure of NiCo2O4 could not only shorten the diffusion path of lithium ions and electrons but also increase the specific surface area, providing more active sites for electrochemical reactions. (2) The CNF with considerable mechanical strength and electrical conductivity could function as an anchor for the NiCo2O4 nanostructure and ensure an efficient electron transfer. (3) The porous structure resulted in a high specific surface area and an effective buffer for the volume changes during the repeated charge-discharge processes. Compared with a conventional hydrothermal method, electrodeposition could significantly simplify the preparation of NiCo2O4, with a shorter preparation period and lower energy consumption. This work provides an alternative strategy to obtain a high performance anode for lithium ion batteries.

Electrodeposition of polypyrrole onto NiTi and the corrosion behaviour of the coated alloy

International Nuclear Information System (INIS)

Flamini, D.O.; Saidman, S.B.

2010-01-01

Polypyrrole (PPy) films were electrodeposited onto nickel--titanium alloy (NiTi) employing sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT or AOT) solutions. Polarizing anodically NiTi samples recovered by PPy in a monomer-free solution increases adhesion of the coating. Electrochemical techniques, scanning electron microscopy (SEM) and element analysis were used in determining the corrosion performance of the coated samples in chloride solution. The polymer improves the corrosion performance at the open circuit potential and at potentials where the bare substrate suffers pitting attack. The improvement in both, adhesion and corrosion performance, is discussed considering substrate/polymer interaction, overoxidation of PPy and the role played by AOT.

Metallic nickel nanorod arrays embedded into ordered block copolymer templates

International Nuclear Information System (INIS)

Seifarth, O.; Krenek, R.; Tokarev, I.; Burkov, Y.; Sidorenko, A.; Minko, S.; Stamm, M.; Schmeisser, D.

2007-01-01

We report on metallic Nickel nanorods prepared by utilizing a mask of ordered nanostructured hollow channels in a block copolymer matrix. These polymeric templates were formed by a self organized process in block copolymer supramolecular assemblies. Nickel was filled into with two different techniques, electrodeposition and washing in. We monitor the formation process of these nanorods by means of atomic force microscopy and synchrotron radiation soft X-ray based photoelectron emission microscopy. The oxidation state of the nickelrods is evaluated with X-ray absorption spectroscopy and X-ray photoelectron spectroscopy at the Ni L edges and lateral distributions of the Ni nanorods were detected with micrometer resolved X-ray absorption spectroscopy. The finding is that the Ni rods were metallic despite their preparation under ambient conditions, inside the particles no hints for NiO complexes were found. This indicates that the polymer protects Ni nanoparticles against oxidation

Studies of micromorphology and current efficiency of zinc electrodeposited from flowing chloride electrolytes

Energy Technology Data Exchange (ETDEWEB)

Mc Vay, Laura [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States); Tobias, Charles W. [Univ. of California, Berkeley, CA (United States)

1986-05-01

Results of a study of the micromorphology and current efficiency of zinc electrodeposited from flowing, acidic chloride solutions are reported. The effects of six variables were examined: flow rate, current density, zinc and hydrogen ion concentration, concentrations of nickel, iron and cadmium impurity ions, and the nature of the substrate. The development of micromorphology was studied in-situ by means of videomicrography and ex-situ by means of scanning electron microscopy. This investigation focused on the formation of grooved deposits, which are found under a wide range of deposition conditions. The major conclusions of this study are: the most important variable determining whether grooved deposits form is the interfacial concentration; large protrusions orient themselves parallel to the flow direction with the orientation starting upstream and progressing downstream; large protrusions become ridges due to growth of the highest current density portions of the electrode under mass transport control. The current efficiency was measured using EDTA titration and weight measurements. The fraction of the current taken by zinc deposition increased with zinc concentration, ranging up to 100%, and decreased with pH. The efficiency of zinc deposition was affected by the flow rate and the substrate employed. Impurities lowered the current efficiency.

Structure, mechanical and magnetic properties of Al4C3 reinforced nickel matrix nanocomposites

Science.gov (United States)

Chaudhari, Alok Kumar; Singh, Dhananjay Kumar; Singh, V. B.

2018-05-01

A new type of nanocomposite, Ni-Al4C3 was prepared using Al4C3 as reinforcement by cathodic co-deposition at different current densities (1.0 to 5.0 A dm‑2) from a nickel acetate-N-methyl formamide (non-aqueous) bath. Influence of current density and incorporation of Al4C3 particles in nickel matrix on the structure and properties of the composite coatings was investigated. Surface morphology and composition of the deposits were determined by SEM and EDAX. Crystallographic structure and orientation of the electrodeposited Ni-Al4C3 composite were studied by x-ray diffraction. Compared to nickel metal, these nanocomposites exhibited finer grains, higher microhardness, improved corrosion resistance and enhanced soft magnetic properties. Composite deposited at higher current densities (>2 A dm‑2) shows mild texturing along (200) plane. The effect of heat treatment on the microstructure, texture and microhardness of the nanocomposites was also investigated.

Electrodeposition of nickel onto steel, using a thermostatic cell and movable anode by a variable current

International Nuclear Information System (INIS)

Vega G, J.D.

1994-01-01

In this work, metallic coatings of nickel was made over carbon steel using two different electrolytic solutions: The Watts's bath and the nickel sulfamate bath, using a pulse variable current. The method use was the traditional method, its means a thermostatic cell and one movable anode, which is a few know technique nowadays, it allow realize depositions away from any laboratory or special workshop, it has the advantage to be a portable dispositive. At last of all the electro depositions the coatings quality was valuable by them physical properties like: adhesion, hardness, wrinkled and thickness. The best results was obtain by the Nickel sulfamate bath and movable anode, less in the thickness, which has higher on the thermostatic cell. The variable current was obtain by a Pulse Generator and a Cathodic galvanometer. (Author)

Effect of Electrodeposition Potential on Composition of CuIn1−xGaxSe2 Absorber Layer for Solar Cell by One-Step Electrodeposition

Directory of Open Access Journals (Sweden)

Rui-Wei You

2014-01-01

Full Text Available CIGS polycrystalline thin films were successfully fabricated by one-step cathodic electrodeposition on Mo-coated glass. In this study, we applied a galvanometry mode with three-electrode potentiostatic systems to produce a constant concentration electroplating solution, which were composed of CuCl2, InCl3, GaCl3, and SeO2. Then these as-electrodeposited films were annealed in argon atmosphere and characterized by X-ray diffraction. The results revealed that annealing treatment significantly improved the crystallinity of electrodeposited films and formed CIGS chalcopyrite structure, but at low applied deposition voltage (−950 mV versus SCE there appeared second phase. The cross-section morphology revealed that applied voltage at −1350 mV versus SCE has uniform deposition, and higher applied voltage made grain more unobvious. The deposition rate and current density are proportional to deposition potential, and hydrogen was generated apparently when applying potential beyond −1750 mV versus SCE. It was found that the CIGS compound did not match exact stoichiometry of Cu : In : Ga : Se =1 : x : 1-x : 2. This result suggests the possibility of controlling the property of thin films by varying the applied potential during electrodeposition.

Electrochemical corrosion measurements on noble electrodeposits

DEFF Research Database (Denmark)

Christoffersen, Lasse; Maahn, Ernst Emanuel

1998-01-01

Novel electrodeposits are compared with hard chrome and electroless Ni-P with respect to production, corrosion resistance and hardness.......Novel electrodeposits are compared with hard chrome and electroless Ni-P with respect to production, corrosion resistance and hardness....

The properties of electrodeposited Zn-Co coatings

Science.gov (United States)

Mahieu, J.; de Wit, K.; de Cooman, B. C.; de Boeck, A.

1999-10-01

The possibility of increasing the corrosion resistance of automotive sheet steel by electrodepositing with Zn-Co alloy coatings was investigated. Process variables during electrodeposition such as current density, electrolyte flow rate, and pH were varied in order to examine their influence on the electroplating process. Cobalt contents varying from 0.2 to 7 wt% were easily obtained. The influence of these process parameters on the characteristics of the coating could be related to the hydroxide suppression mechanism for anomalous codeposition. The structure and the morphology of the coatings were determined using SEM and XRD analysis. Application properties important for coating systems used in the automotive industry, such as friction behavior, adhesion, and corrosion behavior, were investigated on coatings with varying cobalt content. The corrosion resistance of the Zn-Co alloy layers was found to be better than that of pure zinc coatings.

Electrodeposition of thin Pd-Ag films

International Nuclear Information System (INIS)

Hasler, P.; Allmendinger, T.

1993-01-01

Thin Pd-Ag layers were electroplated preferably on brass and on nickel substrates using a two-compartment cell separated by an anion exchange membrane. The weakly alkaline electrolyte contained glycine-glycinate as the major complexing agents. The plating experiments were usually carried out without stirring, at different potentials and temperatures and in the absence or in the presence of sodium benzaldehyde-2,4-disulphonate (BDS). The samples were characterized by scanning electron microscopy and light microscopy. Their compositions were determined analytically by the inductively coupled plasma technique. In addition, the film porosity was tested. Electrodeposition in almost limiting current conditions for both components and without simultaneous hydrogen evolution led to deposits with compositions being in good agreement with the molar metal ratio in the electrolyte (77:23). The best results were achieved between 0 and -50 mV with respect to a reversible hydrogen electrode at 0 C in the presence of BDS. These deposits were bright, had good adherence and exhibited no pores at a film thickness of 1.2 μm. At too negative potentials, the deposits became black and powdery. (orig.)

Apparatus for eliminating electrodeposition of radioactive nuclide

International Nuclear Information System (INIS)

Inomata, Ichiro; Ishibe, Tadao; Matsunaga, Masaaki; Konuki, Ryoichi; Suzuki, Kazunori; Watanabe, Minoru; Tomoshige, Shozo; Kondo, Kozo.

1990-01-01

In a conventional device for eliminating by radioactive nuclides electrodeposition, a liquid containing radioactive nuclides is electrolyzed under a presence of non-radioactive heavy metals and removing radioactive nuclides by electrodepositing them together with the heavy metals. Two anode plates are opposed in an electrolysis vessel of this device. A plurality (4 to 6) of cathode plates are arranged between the anodes in parallel with them and the cathode surfaces opposed to the anodes are insulated. Further, such a plurality of cathode plates are grouped into respective units. Alternatively, the anode plate is made of platinum-plated titanium material and the cathode plate is made of stainless steel. In the thus constituted electrodeposition eliminating device, since the cathode surface directed to the anodes on both ends are insulated, all of electric current from the anode reach the core cathode after flowing around the cathodes at both ends. As a result, there is no substantial difference in the flowing length of the electrolyzing current to each of the cathodes and these is neither difference in the electrodeposition amount. The electrodeposited products are adhered uniformly and densely to the electrodes and, simultaneously, Co-60 and Mn-54, etc. are also electrodeposited. (I.S.)

Magnetic properties of mosaic nanocomposites composed of nickel and cobalt nanowires

Energy Technology Data Exchange (ETDEWEB)

Castillo-Sepúlveda, S.; Corona, R.M. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Altbir, D. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago (Chile); Escrig, J., E-mail: juan.escrig@usach.cl [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago (Chile)

2016-10-15

Mosaic nanocomposites composed of nickel and cobalt nanowires arranged in different configurations were investigated using Monte Carlo simulations and a simple model that considers single-domain structures including length corrections due to the shape anisotropy. Our results showed that for an ordered array both the coercivity and the remanence decrease linearly as a function of the concentration of nickel nanowires. Besides, we obtained that the magnetic properties of an array of a certain hard magnetic material (cobalt) will not change, unless we have more than 50% of nanowires of other soft magnetic material (nickel) in the array. In principle the second material could be other soft magnetic material, but could also be a nonmagnetic material or could even be a situation in which some of the pore arrays were not filled by electrodeposition. Therefore, our results allow us to predict the behavior of magnetic mosaic nanocomposites that are promising candidates for functional electrodes, sensors, and model catalysts. - Highlights: • Mosaic nanocomposites composed of magnetic nanowires were investigated. • Magnetic properties can be adjusted by varying the concentration of nanowires. • Our results allow us to predict the behavior of magnetic mosaic nanocomposites.

Theory and practice of metal electrodeposition

CERN Document Server

Gamburg, Yuliy D

2011-01-01

fills the gap between modern developments in electrochemistry and outdated information on metals electrodeposition currently available in competing titles essential information on the theoretical and practical electrochemistry necessary to investigate modern metal deposition is provided part of the growing literature on electrodeposition

An Effective Electrodeposition Mode for Porous MnO2/Ni Foam Composite for Asymmetric Supercapacitors

Science.gov (United States)

Tsai, Yi-Chiun; Yang, Wein-Duo; Lee, Kuan-Ching; Huang, Chao-Ming

2016-01-01

Three kinds of MnO2/Ni foam composite electrode with hierarchical meso-macroporous structures were prepared using potentiodynamic (PD), potentiostatic (PS), and a combination of PS and PD(PS + PD) modes of electrodeposition. The electrodeposition mode markedly influenced the surface morphological, textural, and supercapacitive properties of the MnO2/Ni electrodes. The supercapacitive performance of the MnO2/Ni electrode obtained via PS + PD(PS + PD(MnO2/Ni)) was found to be superior to those of MnO2/Ni electrodes obtained via PD and PS, respectively. Moreover, an asymmetric supercapacitor device, activated carbon (AC)/PS + PD(MnO2/Ni), utilizing PS + PD(MnO2/Ni) as a positive electrode and AC as a negative electrode, was fabricated. The device exhibited an energy density of 7.7 Wh·kg−1 at a power density of 600 W·kg−1 and superior cycling stability, retaining 98% of its initial capacity after 10,000 cycles. The good supercapacitive performance and excellent stability of the AC/PS + PD(MnO2/Ni) device can be ascribed to its high surface area, hierarchical structure, and interconnected three-dimensional reticular configuration of the nickel metal support, which facilitates electrolyte ion intercalation and deintercalation at the electrode/electrolyte interface and mitigates volume change during repeated charge/discharge cycling. These results demonstrate the great potential of the combination of PS and PD modes for MnO2 electrodeposition for the development of high-performance electrodes for supercapacitors. PMID:28773371

Electrochemical study of nickel from urea-acetamide-LiBr low-temperature molten salt

International Nuclear Information System (INIS)

Li, Min; Gao, Bingliang; Shi, Zhongning; Hu, Xianwei; Wang, Shixing; Li, Liangxing; Wang, Zhaowen; Yu, Jiangyu

2015-01-01

Highlights: • CV results show that the charge transfer process of Ni(II)/Ni in urea-acetamide-LiBr is irreversible. • The reduction process is a single step two-electron transfer process. • Chronoamperometry indicates that the reaction on tungsten electrode involves progressive nucleation. • EDS and XRD analyses confirm that the obtained deposits are pure nickel. -- Abstract: The electrochemical behavior of nickel was studied by cyclic voltammetry and chronoamperometry techniques at 353 K using a tungsten electrode in urea-acetamide-LiBr low-temperature molten salt. The cyclic voltammograms indicate that the reduction of Ni(II) to Ni proceeds via a single-step, two-electron transfer process. Chronoamperometric measurements show that the electrodeposition of nickel on the tungsten electrode involves three-dimensional (3D) progressive nucleation under diffusion-controlled growth at 353 K. Nickel coatings were prepared at different cathodic potentials (−0.70 to −0.85 V) and different temperatures (343–373 K) in urea-acetamide-LiBr molten salt. The deposits were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The SEM images reveal that uniform, dense, and compact deposits were obtained at more positive cathodic potentials within the temperature range of 343–363 K. The EDS and XRD analyses confirm that the obtained deposits are pure nickel

ZnTe Amorphous Semiconductor Nanowires Array Electrodeposited into Polycarbonate Membrane Thin Films

International Nuclear Information System (INIS)

Ohgai, T; Ikeda, T; Ohta, J

2013-01-01

ZnTe amorphous semiconductor nanowires array was electrodeposited into the nanochannels of ion-track etched polycarbonate membrane thin films from acidic aqueous solution at 313 K. ZnTe electrodeposits with Zn-rich composition was obtained over the wide range of cathode potential from −0.8 V to −1.1 V and the growth rate of ZnTe amorphous nanowires was around 3 nm.sec −1 at the cathode potential of −0.8 V. Cylindrical shape of the nanowires was precisely transferred from the nanochannels and the aspect ratio reached up to ca. 40. ZnTe amorphous phase electrodeposited at 313 K was crystallized by annealing at 683 K and the band gap energy of ZnTe crystalline phase reached up to ca. 2.13 eV.

Nickel recovery from electronic waste II Electrodeposition of Ni and Ni–Fe alloys from diluted sulfate solutions

Energy Technology Data Exchange (ETDEWEB)

Robotin, B. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, RO-400028 Cluj-Napoca (Romania); Ispas, A. [Fachgebiet Elektrochemie und Galvanotechnik II, Technische Universität Ilmenau, D-98693 Ilmenau (Germany); Coman, V. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, RO-400028 Cluj-Napoca (Romania); Bund, A. [Fachgebiet Elektrochemie und Galvanotechnik II, Technische Universität Ilmenau, D-98693 Ilmenau (Germany); Ilea, P., E-mail: pilea@chem.ubbcluj.ro [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, RO-400028 Cluj-Napoca (Romania)

2013-11-15

Highlights: • Ni can be recovered from EG wastes as pure Ni or as Ni–Fe alloys. • The control of the experimental conditions gives a certain alloy composition. • Unusual deposits morphology shows different nucleation mechanisms for Ni vs Fe. • The nucleation mechanism was progressive for Ni and instantaneous for Fe and Ni–Fe. - Abstract: This study focuses on the electrodeposition of Ni and Ni–Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni{sup 2+}/Fe{sup 2+} ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits’ thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni–Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni–Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni–Fe, the obtained data points are best fitted to an instantaneous nucleation model.

Applications of x ray absorption fine structure to the in situ study of the effect of cobalt in nickel hydrous oxide electrodes for fuel cells and rechargeable batteries

Science.gov (United States)

Kim, Sunghyun; Tryk, Donald A.; Scherson, Daniel A.; Antonio, Mark R.

1993-01-01

Electronic and structural aspects of composite nickel-cobalt hydrous oxides have been examined in alkaline solutions using in situ X-ray absorption fine structure (XAFS). The results obtained have indicated that cobalt in this material is present as cobaltic ions regardless of the oxidation state of nickel in the lattice. Furthermore, careful analysis of the Co K-edge Extended X-ray absorption fine structure data reveals that the co-electrodeposition procedure generates a single phase, mixed metal hydrous oxide, in which cobaltic ions occupy nickel sites in the NiO2 sheet-like layers and not two intermixed phases each consisting of a single metal hydrous oxide.

A novel blister test to evaluate the interface strength between nickel coating and low carbon steel substrate

International Nuclear Information System (INIS)

Xiao, L.H.; Su, Xu Ping.; Wang, J.H.; Zhou, Y.C.

2009-01-01

A novel blister test theory model was developed based on the bending theory of beams for assessing the interface strength of the nickel coating/low carbon steel substrate material system. The strain energy of the debonded nickel coating was calculated analytically and by finite element analysis, respectively. The analytic solutions agree well with the FE calculation results. Some blister tests were carried out on the WII-5 Computer Controlled Material Mechanical Properties Testing Machine, using four nickel-coated specimens type-A, -B, -C and -D which were electrodeposited on low carbon steel substrate. Here, types A, B, C and D correspond to the nickel coating thickness of 5 μm, 10 μm, 15μm and 25μm, respectively. The interface strength, evaluated by this blister test method, is 196.86 J/m 2 and 269.40 J/m 2 for type-C and -D specimens, respectively. However the tests demonstrate that the type-A and -B specimens were cut through by the spindle and no delaminations between the coating and the substrate could be found

The effect of current density and saccharin addition on the grain size of nickel coatings

Energy Technology Data Exchange (ETDEWEB)

Uhm, Young Rang; Park, Keun Yung; Son, Kwang Jae; Shim, Young Ho; Choi, Sun Ju [KAERI, Daejeon (Korea, Republic of)

2012-10-15

Recently, the main advantage of a radioisotope 'fuel' is concentrated, because it is 'burned' at the rate of the isotopes half life. In other words, given a half life of 100 years, a nuclear battery would still produce half of its initial starting power after 100 years. A speck of a radioisotope like nickel 63, for example, contains enough energy to power a nano nuclear battery for decades, and to do so safely. Ni 63, a beta radiation source, is prepared by electrical deposition of radioactive Ni 63 ions on thin non radioactive nickel foil. Ni 63 plating is similar to other electroplating processes that employ soluble metal anodes. It requires the passage of a direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. The charged Ni ions are formed by sulfate, sulfamate, chloride, and a Watts bath. However, the charged Ni 63 ions are formed by dissolving metal Ni 63. To establish the coating condition of Ni 63, non radioactive metal Ni particles were dissolved in an acid solution and electroplated on the Ni sheet. A continuous increase in the grain size versus current density has also been recognized in the direct current electrodeposition of nickel coating. On the other hand, A runa et al. reported that the current density has no significant effect on the grain size of nickel electro deposits. A review of the literature shows that saccharin has often been added to a nickel plating bath since the 1980s to improve the ductility and brightness, and in later periods as a grain refiner agent. In the present paper, not only the preparation of the Ni plating solution prepared by dissolving metal particles but also an optimization of the deposition conditions, such as the influence of current density and saccharin concentration on the grain size, was investigated. The proposed model can also be applied for radioactive Ni 63 electroplating.

The effect of current density and saccharin addition on the grain size of nickel coatings

International Nuclear Information System (INIS)

Uhm, Young Rang; Park, Keun Yung; Son, Kwang Jae; Shim, Young Ho; Choi, Sun Ju

2012-01-01

Recently, the main advantage of a radioisotope 'fuel' is concentrated, because it is 'burned' at the rate of the isotopes half life. In other words, given a half life of 100 years, a nuclear battery would still produce half of its initial starting power after 100 years. A speck of a radioisotope like nickel 63, for example, contains enough energy to power a nano nuclear battery for decades, and to do so safely. Ni 63, a beta radiation source, is prepared by electrical deposition of radioactive Ni 63 ions on thin non radioactive nickel foil. Ni 63 plating is similar to other electroplating processes that employ soluble metal anodes. It requires the passage of a direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. The charged Ni ions are formed by sulfate, sulfamate, chloride, and a Watts bath. However, the charged Ni 63 ions are formed by dissolving metal Ni 63. To establish the coating condition of Ni 63, non radioactive metal Ni particles were dissolved in an acid solution and electroplated on the Ni sheet. A continuous increase in the grain size versus current density has also been recognized in the direct current electrodeposition of nickel coating. On the other hand, A runa et al. reported that the current density has no significant effect on the grain size of nickel electro deposits. A review of the literature shows that saccharin has often been added to a nickel plating bath since the 1980s to improve the ductility and brightness, and in later periods as a grain refiner agent. In the present paper, not only the preparation of the Ni plating solution prepared by dissolving metal particles but also an optimization of the deposition conditions, such as the influence of current density and saccharin concentration on the grain size, was investigated. The proposed model can also be applied for radioactive Ni 63 electroplating

Deuterium retention in molten salt electrodeposition tungsten coatings

International Nuclear Information System (INIS)

Zhou, Hai-Shan; Xu, Yu-Ping; Sun, Ning-Bo; Zhang, Ying-Chun; Oya, Yasuhisa; Zhao, Ming-Zhong; Mao, Hong-Min; Ding, Fang; Liu, Feng; Luo, Guang-Nan

2016-01-01

Highlights: • We investigate D retention in electrodeposition W coatings. • W coatings are exposed to D plasmas in the EAST tokamak. • A cathodic current density dependence on D retention is found. • Electrodeposition W exhibits lower D retention than VPS-W. - Abstract: Molten salt electrodeposition is a promising technology to manufacture the first wall of a fusion reactor. Deuterium (D) retention behavior in molten salt electrodeposition tungsten (W) coatings has been investigated by D-plasma exposure in the EAST tokamak and D-ion implantation in an ion beam facility. Tokamak exposure experiments demonstrate that coatings prepared with lower current density exhibit less D retention and milder surface damage. Deuterium-ion implantation experiments indicate the D retention in the molten salt electrodeposition W is less than that in vacuum plasma spraying W and polycrystalline W.

Deuterium retention in molten salt electrodeposition tungsten coatings

Energy Technology Data Exchange (ETDEWEB)

Zhou, Hai-Shan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Xu, Yu-Ping [Science Island Branch of Graduate School, University of Science and Technology of China, Hefei (China); Sun, Ning-Bo; Zhang, Ying-Chun [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing (China); Oya, Yasuhisa [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Zhao, Ming-Zhong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Mao, Hong-Min [Science Island Branch of Graduate School, University of Science and Technology of China, Hefei (China); Ding, Fang; Liu, Feng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Luo, Guang-Nan, E-mail: gnluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Science Island Branch of Graduate School, University of Science and Technology of China, Hefei (China); Hefei Center for Physical Science and Technology, Hefei (China); Hefei Science Center of Chinese Academy of Science, Hefei (China)

2016-12-15

Highlights: • We investigate D retention in electrodeposition W coatings. • W coatings are exposed to D plasmas in the EAST tokamak. • A cathodic current density dependence on D retention is found. • Electrodeposition W exhibits lower D retention than VPS-W. - Abstract: Molten salt electrodeposition is a promising technology to manufacture the first wall of a fusion reactor. Deuterium (D) retention behavior in molten salt electrodeposition tungsten (W) coatings has been investigated by D-plasma exposure in the EAST tokamak and D-ion implantation in an ion beam facility. Tokamak exposure experiments demonstrate that coatings prepared with lower current density exhibit less D retention and milder surface damage. Deuterium-ion implantation experiments indicate the D retention in the molten salt electrodeposition W is less than that in vacuum plasma spraying W and polycrystalline W.

ANOMALOUS ELECTRODEPOSITION OF Fe-Ni ALLOY COATING FROM SIMPLE AND COMPLEX BATHS AND ITS MAGNETIC PROPERTY

Directory of Open Access Journals (Sweden)

M A Islam

2010-03-01

Full Text Available Electrodeposition of Fe-Ni thin films has been carried on copper substrate under various electrodeposition conditions from two simple and six complex baths. Sulfate baths composing of NiSO4. 7H2O, FeSO4.7H2O, H3BO3 and Na2SO4KEYWORDS: Anomalous Electrodeposition, Fe-Ni Coating, Complexing agent, Current Density, Magnetic Property. 1. INTRODUCTION Alloy electrodeposition technologies can extend tremendously the potential of electrochemical deposition processes to provide coatings that require unique mechanical, chemical and physical properties [1]. There has been a great research interest in the development and characterization of iron-nickel (Fe-Ni thin films due to their operational capacity, economic interest, magnetic and other properties [2]. Due to their unique low coefficient of thermal expansion (CTE and soft magnetic properties, Fe-Ni alloys have been used in industrial applications for over 100 years [3]. Typical examples of applications that are based on the low CTE of Fe-Ni alloys include: thermostatic bimetals, glass sealing, integrated circuit packaging, cathode ray tube, shadow masks, membranes for liquid natural gas tankers; applications based on the soft magnetic properties include: read-write heads for magnetic storage, magnetic actuators, magnetic shielding, high performance transformer cores. comprise the simple baths whereas complex baths were prepared by adding ascorbic acid, saccharin and citric acid in simple baths. The effect of bath composition, pH and applied current density on coating appearance, composition, morphology and magnetic property were studied. Wet chemical analysis technique was used to analyze the coating composition whereas SEM and VSM were used to study the deposit morphology and magnetic property respectively. Addition of complexing agents in plating baths suppressed the anomalous nature of Fe-Ni alloy electrodeposition. Coatings obtained from simple baths were characterized by coarse grained non

Liquid Membrane System for Extraction and Electrodeposition of Lead(II During Electrodialysis

Directory of Open Access Journals (Sweden)

Sadyrbaeva Tatiana

2017-05-01

Full Text Available A novel method for lead(II removal from aqueous acidic solutions is presented. The method involves electrodialysis through bulk liquid membranes accompanied by electrodeposition of metal from the cathodic solution. Solutions of di(2-ethylhexylphosphoric acid with admixtures of tri-n-octylamine in 1,2-dichloroethane were used as the liquid membranes. The effects of the main electrodialysis parameters as well as of the composition of the liquid membranes and aqueous solutions on the lead(II transport rate are studied. The optimal conditions are determined. A possibility of effective single-stage transfer of lead(II through the liquid membrane into dilute solutions of perchloric, nitric and acetic acids is demonstrated. Dense and adherent lead electrodeposits are obtained from perchloric acid solutions. Maximum extraction degree of 93 % and electrodeposition degree of ~60 % are obtained during 5 h of electrodialysis.

Cationic electrodepositable coating composition comprising lignin

Science.gov (United States)

Fenn, David; Bowman, Mark P; Zawacky, Steven R; Van Buskirk, Ellor J; Kamarchik, Peter

2013-07-30

A cationic electrodepositable coating composition is disclosed. The present invention in directed to a cationic electrodepositable coating composition comprising a lignin-containing cationic salt resin, that comprises (A) the reaction product of: lignin, an amine, and a carbonyl compound; (B) the reaction product of lignin, epichlorohydrin, and an amine; or (C) combinations thereof.

Bi-doped PbO2 anodes: Electrodeposition and physico-chemical properties

International Nuclear Information System (INIS)

Shmychkova, O.; Luk’yanenko, T.; Velichenko, A.; Meda, L.; Amadelli, R.

2013-01-01

The influence of bismuth ions on kinetics of lead dioxide electrodeposition from methanesulfonate electrolytes and physico-chemical properties of obtained coatings were studied. Experimental results are consistent with a mechanism previously proposed in the literature for lead dioxide electrodeposition. The presence of bismuth ions in the electrodeposition solution causes a decrease of rate constants of lead dioxide formation due to co-adsorption phenomena. Deposits from solutions containing bismuth ions appear shiny dark grey, and show good adhesion to metal support. SEM images reveal a compact structure with spindle-shaped submicron and nanosized crystals and X-ray diffractograms demonstrated that incorporation of bismuth diminishes the size of crystal particles. Oxygen evolution was investigated to test electrocatalytic activity. It is shown, that oxygen overpotential on modified electrodes is significantly higher than on non-modified PbO 2 -electrode, which depends on bismuth content in deposit and segregation of bismuth that induces surface heterogeneity due to sites with different electroactivity for water oxidation

Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China.

Science.gov (United States)

Chen, Kai; Liao, Qi Lin; Ma, Zong Wei; Jin, Yang; Hua, Ming; Bi, Jun; Huang, Lei

2015-04-01

Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population.

Experiments, modeling and simulation of the magnetic behavior of inhomogeneously coated nickel/aluminum hybrid foams

Energy Technology Data Exchange (ETDEWEB)

Jung, A., E-mail: anne.jung@mx.uni-saarland.de [Universität des Saarlandes, Institute of Applied Mechanics, Campus A4 2, 66123 Saarbrücken (Germany); Klis, D., E-mail: d.klis@lte.uni-saarland.de [Universität des Saarlandes, Laboratory for Electromagnetic Theory, Campus C6 3, 66123 Saarbrücken (Germany); Goldschmidt, F., E-mail: f.goldschmidt@mx.uni-saarland.de [Universität des Saarlandes, Institute of Applied Mechanics, Campus A4 2, 66123 Saarbrücken (Germany)

2015-03-15

Open-cell metal foams are used as lightweight construction elements, energy absorbers or as support for catalytic coatings. Coating of open-cell metal foams is not only used for catalytic applications, but it leads also to tremendous increase in stiffness and energy absorption capacity. A non-line of sight coating technique for complex 3D structures is electrodeposition. Unfortunately, due to the 3D porosity and the related problems in mass transport limitation during the deposition, it is not possible to produce homogeneously coated foams. In the present contribution, we present a semi-non-destructive technique applicable to determine the coating thickness distribution of magnetic coatings by measuring the remanent magnetic field of coated foams. In order to have a closer look at the mass transport mechanism, a numerical model was developed to predict the field scans for different coating thickness distributions in the foams. For long deposition times the deposition reaches a steady state whereas a Helmholtz equation is sufficient to predict the coating thickness distribution. The applied current density could be identified as the main influencing parameter. Based on the developed model, it is possible to improve the electrodeposition process and hence the homogeneity in the coating thickness of coated metal foams. This leads to enhanced mechanical properties of the hybrid foams and contributes to better and resource-efficient energy absorbers and lightweight materials. - Highlights: • Production of hybrid foams by electrodeposition of nickel on open-cell metal foams. • Magnetic field scans for visualization of spatial coating thickness distribution. • Modeling of magnetic fields of inhomogeneously coated hybrid foams. • Investigation of mass transport limitation during coating by a Helmholtz equation. • Increasing coating homogeneity by use of low current densities and deposition rates.

Proposal of fatigue crack growth rate curve in air for nickel-base alloys used in BWR

International Nuclear Information System (INIS)

Ogawa, Takuya; Itatani, Masao; Nagase, Hiroshi; Aoike, Satoru; Yoneda, Hideki

2013-01-01

When the defects are detected in the nuclear components in Japan, structural integrity assessment should be performed for the technical judgment on continuous service based on the Rules on Fitness-for-Service for Nuclear Power Plants of the Japan Society of Mechanical Engineers Code (JSME FFS Code). Fatigue crack growth analysis is required when the cyclic loading would be applied for the components. Recently, fatigue crack growth rate curve in air environment for Nickel-base alloys weld metal used in BWR was proposed by the authors and it was adopted as a code case of JSME FFS Code to evaluate the embedded flaw. In this study, fatigue crack growth behavior for heat-affected zone (HAZ) of Nickel-base alloys in air was investigated. And a unified fatigue crack growth rate curve in air for HAZ and weld metal of Nickel-base alloys used in BWR was evaluated. As a result, it was found that the curve for weld metal could be applied as a curve for both HAZ and weld metal since moderately conservative assessment of fatigue crack growth rate of HAZ is possible by the curve for weld metal in the Paris region. And the threshold value of stress intensity far range (ΔK th ) is determined to 3.0 MPa√m based on the fatigue crack growth rate of HAZ. (author)

Experimental Investigation of the Electro Co-deposition of (Zinc-Nickel Alloy

Directory of Open Access Journals (Sweden)

Ekhlas Abdulrahman Salman

2018-02-01

Full Text Available abstract An experimental investigation has been carried out for zinc-nickel (Zn-Ni electro-deposition using the constant applied current technique. Weight difference approach method was used to determine the cathode current efficiency and deposit thickness. Also, the influence effect of current density on the deposition process, solderability, and porosity of the plating layer in microelectronic applications were examined. The bath temperature effect on nickel composition and the form of the contract was studied using Scanning Electron Microscope (SEM. Moreover, elemental nature of the deposition was analyzed by Energy Dispersive X-Ray (EDX. It has been found that the best bath temperature was 40˚C, specifically at a concentration of 73 g/L of NiCl2.6H2O, has a milestone influence on the nickel composition and structure of the deposits. The potential is a major factor influencing the deposition coating alloy which is adjusted by the operations of the cathodic polarization; rather than the standard potential of the two metals as determined by the e.m.f. series. The anomalous deposition was obtained at a current density lower than 0.8 A/dm2, while normal deposition occurred at current densities less than 1.2 A/dm2. Corrosion behavior was exhibited by the bath and for performance was carried out, and it shows that the best corrosion performance was for nickel composition of 10-12.6 wt%.

Deformation and fracture in micro-tensile tests of freestanding electrodeposited nickel thin films

International Nuclear Information System (INIS)

Yang, Y.; Yao, N.; Soboyejo, W.O.; Tarquinio, C.

2008-01-01

In situ scanning electron microscopy micro-tensile tests were conducted on freestanding LIGA nickel thin films of two thicknesses (70 and 270 μm). The deformation and fracture mechanisms were elucidated by in situ scanning electron microscopy imaging and ex situ fractographic analysis. Due to the film microstructural gradient, an apparent thickness effect on the film yield strengths was observed, which was then rationalized with a continuum micromechanics model

Role of nickel in high rate methanol degradation in anaerobic granular sludge bioreactors

Science.gov (United States)

Fermoso, Fernando G.; Collins, Gavin; Bartacek, Jan; O’Flaherty, Vincent

2008-01-01

The effect of nickel deprivation from the influent of a mesophilic (30°C) methanol fed upflow anaerobic sludge bed (UASB) reactor was investigated by coupling the reactor performance to the evolution of the Methanosarcina population of the bioreactor sludge. The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5–15 g COD l−1 day−1 for 191 days. A clear limitation of the specific methanogenic activity (SMA) on methanol due to the absence of nickel was observed after 129 days of bioreactor operation: the SMA of the sludge in medium with the complete trace metal solution except nickel amounted to 1.164 (±0.167) g CH4-COD g VSS−1 day−1 compared to 2.027 (±0.111) g CH4-COD g VSS−1 day−1 in a medium with the complete (including nickel) trace metal solution. The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge. Continuation of the UASB reactor operation with the nickel limited sludge lead to incomplete methanol removal, and thus methanol accumulation in the reactor effluent from day 142 onwards. This methanol accumulation subsequently induced an increase of the acetogenic activity in the UASB reactor on day 160. On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased. Inclusion of 0.5 μM Ni (dosed as NiCl2) to the influent from day 165 onwards lead to the recovery of the methanol removal efficiency to 99% without VFA accumulation within 2 days of bioreactor operation. PMID:18247139

High-speed jet electrodeposition and microstructure of nanocrystalline Ni-Co alloys

International Nuclear Information System (INIS)

Qiao Guiying; Jing Tianfu; Wang Nan; Gao Yuwei; Zhao Xin; Zhou Jifeng; Wang Wei

2005-01-01

The jet electrodeposition from watts baths with a device of electrolyte jet was carried out to prepare nano-crystalline cobalt-nickel alloys. The influence of the concentration of Co 2+ ions in the electrolyte and electrolysis parameters, such as the cathodic current density, the temperature as well as the electrolyte jet speed, on the chemistry and microstructure of Ni-Co-deposit alloys were investigated. Experimental results indicated that increasing the Co 2+ ions concentration in the bath, the electrolyte jet speed and decreasing of the cathodic current density and decrease of the electrolyte temperature all results in an increase of cobalt content in the alloy. Detailed microstructure changes upon the changes of alloy composition and experimental conditions were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD results show the Ni-Co solid solution was formed through the jet electrodeposition. Phase constitution of solid solution changes progressively under different electrolyte concentration. Alloys with low Co concentration exhibit single phase of face-centered cubic (fcc) structure; The Co concentration over 60.39 wt.%, the alloys are composed of face-centered cubic (fcc) phase and hexagonal close-packed (hcp) phase. Furthermore, the formation of the nanostructured Ni-Co alloy deposit is investigated. Increasing the Co 2+ ions concentration in the bath, the cathodic current density, the electrolyte temperature and the electrolyte jet speed all result in the finer grains in the deposits. Additives such as saccharin in the electrolyte also favor the formation of the finer grains in the alloy deposits

Electrodeposited nanoparticles: properties and photocatalytic applications

OpenAIRE

Sheridan, Eoin E.

2009-01-01

The work presented in this thesis reports on fundamental studies into electrodeposition of gold and silver nanoparticulate spheroids on a conducting substrate, Fluorine-doped tin-oxide, and the manipulation of the electrodeposition conditions in order to influence and control the size and surface concentration of spheroids. Methods to control the deposition included chemical modification of the surface with an adsorbed monolayer of 3-aminopropyldimethylmethoxysilane, and manipulation of...

Nickel extraction from nickel matte

Science.gov (United States)

Subagja, R.

2018-01-01

In present work, the results of research activities to make nickel metal from nickel matte are presented. The research activities were covering a) nickel matte characterization using Inductively Couple plasma (ICP), Electron Probe Micro Analyzer (EPMA) and X-Ray Diffraction (XRD), b) nickel matte dissolution process to dissolve nickel from nickel matte into the spent electrolyte solutions that contains hydrochloric acid, c) purification of nickel chloride leach solution by copper cementation process to remove copper using nickel matte, selective precipitation process to remove iron, solvent extraction using Tri normal octyl amine to separate cobalt from nickel chloride solutions and d) Nickel electro winning process to precipitate nickel into the cathode surface from purified nickel chloride solution by using direct current. The research activities created 99, 72 % pure nickel metal as the final product of the process.

Improvement in high-voltage and high rate cycling performance of nickel-rich layered cathode materials via facile chemical vapor deposition with methane

International Nuclear Information System (INIS)

Hyuk Son, In; Park, Kwangjin; Hwan Park, Jong

2017-01-01

Nickel-rich layered-oxide materials are considered promising candidates for application as cathode material in high-energy lithium ion batteries. However, their cycling performance at high voltages and rate conditions require further improvement for the purpose of commercialization. Here, we report on the facile surface modification of nickel-rich layered oxide by chemical vapor deposition with methane which yields a conductive and protective artificial solid electrolyte interphase layer consisting of amorphous carbon, alkyl lithium carbonate, and lithium carbonate. We examine the mechanism of the protective layer formation and structural deformation of the nickel-rich layered oxide during chemical vapor deposition with methane. Via optimizing the reaction conditions, we improve the electrical conductivity as well as the interfacial stability of the nickel-rich layered oxide without inducing structural deformation. The surface-modified nickel-rich layered oxide exhibits an improved performance due to the resulting enhanced rate capability, high initial efficiency, and long cycle life at high voltage (>4.5 V).

Preparation of 235U target by electrodeposition

International Nuclear Information System (INIS)

Chen Qiping; Zhong Wenbin; Li Yougen

2004-12-01

A target for the production of fission 99 Mo in a nuclear reactor is composed of an enclosed, cylindrical vessel. Preferable vessel is comprised of stainless steel, having a thin, continuous, uniform layer of 235 U integrally bonded to its inner walls. Two processes are introduced for electrodepositing uranium on to the inner walls of the vessel. One processes is electrodepositing UO 2 from UO 2 (NO 3 ) 2 -(NH 4 ) 2 CO 4 ·H 2 O solution; the other is electrodepositing pure uranium metal from molten salt. Its plating efficiency and plating quantity from a molten bath is higher than UO 2 from the aqueous system. (authors)

Effects of Gold Substrates on the Intrinsic and Extrinsic Activity of High-Loading Nickel-Based Oxyhydroxide Oxygen Evolution Catalysts

DEFF Research Database (Denmark)

Chakthranont, Pongkarn; Kibsgaard, Jakob; Gallo, Alessandro

2017-01-01

We systematically investigate the effects of Au substrates on the oxygen evolution activities of cathodically electrodeposited nickel oxyhydroxide (NiOOH), nickel–iron oxyhydroxide (NiFeOOH), and nickel–cerium oxyhydroxide (NiCeOOH) at varying loadings from 0 to 2000 nmol of metal/cm2. We determi...... high geometric current densities on flat substrates. By investigating the mass and site specific activities as a function of loading, we bridge the practical geometric activity to the fundamental intrinsic activity....

Rocking disc electro-deposition of copper films on Mo/MoSe{sub 2} substrates

Energy Technology Data Exchange (ETDEWEB)

Cummings, Charles Y.; Frith, Paul E. [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Zoppi, Guillaume; Forbes, Ian [Northumbria Photovoltaics Applications Centre, Northumbria University, NE1 8ST (United Kingdom); Rogers, Keith D. [Cranfield Health, Cranfield University, Shrivenham Campus, Swindon, SN6 8LA (United Kingdom); Lane, David W. [Department of Applied Science, Security and Resilience, Cranfield University, Shrivenham, Swindon, SN6 8LA (United Kingdom); Marken, Frank, E-mail: F.Marken@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

2011-08-31

A novel electro-deposition method based on a rocking disc system with {pi}/3 amplitude and variable frequency is introduced. Uniform copper films were deposited from a 0.1 M CuSO{sub 4}/3.0 M NaOH/0.2 M sorbitol bath directly onto 12.1 cm{sup 2} Mo/MoSe{sub 2} substrates with X-ray diffraction showing a thickness variation of {+-}5% over this area. Investigation of the mass transport conditions suggests (i) uniform diffusion over the sample, (ii) a rate of mass transport proportional to the square root of the rocking rate, and (iii) turbulent conditions, which are able to dislodge gas bubbles during electro-deposition.

Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

OpenAIRE

Idris, Jamaliah; Christian, Chukwuekezie; Gaius, Eyu

2013-01-01

Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC) and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis par...

Protection of uranium by electrodeposition of nickel and diffusion; Protection de l'uranium par nickelage electrolytique et diffusion

Energy Technology Data Exchange (ETDEWEB)

Chauvin, G; Coriou, H; Hure, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

This work forms part of the overall scheme for investigating uranium canning for nuclear reactors. It is necessary to: - Protect the fuel (uranium) against corrosion by the cooling medium (heavy water, CO{sub 2}, etc.), in the case of a rupture of the can; - Avoid dangerous U-Al diffusion (when it is question of an aluminium can) by using an intermediate layer of a metal whose rate of diffusion in uranium is very much less than that of aluminium under the same conditions. In the present work based on the use of an intermediate layer of nickel the following points are apparent: 1) After having treated the uranium surface it is possible to electroplate nickel on it in such a way that after annealing without the application of any pressure these deposits give a very good intermetallic U-Ni diffusion. Though this diffusion is inferior to that of the UAl system, it enables the protection to be reinforced and thus the corrosion resistance to be increased. 2) When no other factor varies, the experiments show that the quality of the diffusion zones obtained depends on the nature of the electrolytic nickel bath. 3) The classical nickel baths used previously for this type of work contain 20 to 40 g/l of boric acid acting as an electrolytic buffer. As a result of this, the deposits are highly contaminated by boron (400 to 500 ppm of boron). We shall show that with a bath which does not contain nuclear poisons, a very clean U-Ni diffusion zone can be obtained. 4) After annealing for 100 hours at 700 deg. C, microscopic examination of the diffusion front reveals the existence of five layers under bright field illumination and six Layers in polarised light: at least four of these layers are well crystallised. 5) Important irregularities in the interface between uranium and the first intermetallic compound U{sub 6}Ni seem to be result of barriers to the diffusion caused by certain impurities in the uranium. 6) Of the seven definite compounds which can be formed during the

Electrodeposited Pt for cost-efficient and flexible dye-sensitized solar cells

International Nuclear Information System (INIS)

Kim, Seok-Soon; Nah, Yoon-Chae; Noh, Yong-Young; Jo, Jang; Kim, Dong-Yu

2006-01-01

Pt electrodes were prepared by direct and pulse current electrodeposition for use as counter electrodes in dye-sensitized solar cells. Scanning electron microscope and transmission electron microscope images confirmed the formation of uniform Pt nanoclusters of ∼40 nm composed of 3 nm nanoparticles, when the pulse current electrodeposition method was used, as opposed to the dendritic growth of Pt by the results from direct current electrodeposition. By applying pulse electrodeposited Pt which has a 1.86 times higher surface area compared to direct current electrodeposited Pt, short-circuit current and conversion efficiency were increased from 10.34 to 14.11 mA/cm 2 and from 3.68 to 5.03%, respectively. In addition, a flexible solar cell with a pulse current electrodeposited Pt counter electrode with a conversion efficiency of 0.86% was demonstrated

Electrodeposition of amine-terminatedpoly(ethylene glycol) to titanium surface

International Nuclear Information System (INIS)

Tanaka, Yuta; Doi, Hisashi; Iwasaki, Yasuhiko; Hiromoto, Sachiko; Yoneyama, Takayuki; Asami, Katsuhiko; Imai, Hachiro; Hanawa, Takao

2007-01-01

The immobilization of poly(ethylene glycol), PEG, to a solid surface is useful to functionalize the surface, e.g., to prevent the adsorption of proteins. No successful one-stage technique for the immobilization of PEG to base metals has ever been developed. In this study, PEG in which both terminals or one terminal had been modified with amine bases was immobilized onto a titanium surface using electrodeposition. PEG was dissolved in a NaCl solution, and electrodeposition was carried out at 310 K with - 5 V for 300 min. The thickness of the deposited PEG layer was evaluated using ellipsometry, and the bonding manner of PEG to the titanium surface was characterized using X-ray photoelectron spectroscopy after electrodeposition. The results indicated that a certain amount of PEG was adsorbed on titanium through both electrodeposition and immersion when PEG was terminated by amine. However, terminated amines existed at the surface of titanium and were combined with titanium oxide as N-HO by electrodeposition, while amines randomly existed in the molecule and showed an ionic bond with titanium oxide by immersion. The electrodeposition of PEG was effective for the inhibition of albumin adsorption. This process is useful for materials that have electroconductivity and a complex morphology

Electrodeposition of Radium

International Nuclear Information System (INIS)

Crespo, M.T.; Jimenez, A.S.

1996-01-01

A study of different electrodeposition methods of radium for its measurement by alpha-spectrometry is presented. The recommended procedure uses an aqueous solution of ammonium oxalate and nitric acid in the presence of microgram amounts of platinum as electrolyte

Electrodeposition of copper from a copper sulfate solution using a packed-bed continuous-recirculation flow reactor at high applied electric current

Directory of Open Access Journals (Sweden)

Meshaal F. Alebrahim

2015-09-01

Full Text Available The purpose of this study is mainly to investigate the performance of a packed-bed continuous-recirculation flow reactor at high applied electric current in removing copper, Cu(II, from simulated electrolyte by electrodeposition. The effects of pHo, circulation rate of flow, initial copper concentration, intensity of the applied current and the method of application of electric current, as to have a constant value during all the time of electrolysis or to be decreased with time, on copper electrodeposition and current efficiency are revealed. The results showed that the increase in pH (provided not lead to the deposition of Cu(OH2, initial concentration of the copper and flow rate increased the electrodeposition of copper as well as improved current efficiency. However, increasing intensity of the applied electric current led to an increase in the electrodeposition of copper and decreased electrical efficiency. It was also observed that reducing the intensity of applied electric current with time during the electrolysis process while maintaining other operating variables constant led to a significant reduction in the consumption of electrical energy used in the process of copper removal by electrodeposition; a reduction of 41.6% could be achieved.

Physical and chemical evaluation of the effect of a magnetic field on the electrodeposition of Ni in low carbon steel; Evaluacion fisica y quimica del efecto de un campo magnetico en la electrodeposicion de Ni en acero bajo carbono

Energy Technology Data Exchange (ETDEWEB)

Campo G, G. A.

2015-07-01

In this study nickel coatings were obtained, with and without the presence of magnetic field at 60 degrees Celsius for 7, 12 and 17 minutes on substrates of AISI 1018 carbon steel, from a classical type Watts solution. The properties of the coatings were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy, hardness tester and roughness tester, the electrochemical behavior of the films was also studied through RP and EIE and also capacitance calculations, corrosion rate and thickness were made. In general, the magnetic field has a negative influence on the physical and chemical properties of an electrodeposited Ni steel AISI 1018. The details are discussed in this research. (Author)

Carbon formation on nickel and nickel-copper alloy catalysts

Energy Technology Data Exchange (ETDEWEB)

Alstrup, I.; Soerensen, O.; Rostrup-Nielsen, J.R. [Haldor Topsoe Research Labs., Lyngby (Denmark); Tavares, M.T.; Bernardo, C.A.

1998-05-01

Equilibrium, kinetic and morphological studies of carbon formation in CH{sub 4} + H{sub 2}, CO, and CO + H{sub 2} gases on silica supported nickel and nickel-copper catalysts are reviewed. The equilibrium deviates in all cases from graphite equilibrium and more so in CO + CO{sub 2} than in CH{sub 4} + H{sub 2}. A kinetic model based on information from surface science results with chemisorption of CH{sub 4} and possibly also the first dehydrogenation step as rate controlling describes carbon formation on nickel catalyst in CH{sub 4} + H{sub 2} well. The kinetics of carbon formation in CO and CO + H{sub 2} gases are in agreement with CO disproportionation as rate determining step. The presence of hydrogen influences strongly the chemisorption of CO. Carbon filaments are formed when hydrogen is present in the gas while encapsulating carbon dominates in pure CO. Small amounts of Cu alloying promotes while larger amounts (Cu : Ni {>=} 0.1) inhibits carbon formation and changes the morphology of the filaments (``octopus`` carbon formation). Adsorption induced nickel segregation changes the kinetics of the alloy catalysts at high carbon activities. Modifications suggested in some very recent papers on the basis of new results are also briefly discussed. (orig.) 31 refs.

Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

Directory of Open Access Journals (Sweden)

Jamaliah Idris

2013-01-01

Full Text Available Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis parameters, such as cathodic current density and temperature at constant pH, on electrodeposition and microstructure of Ni-Co alloys were examined. A homogeneous surface morphology was obtained at all current densities of the plated samples, and it was evident that the current density and temperature affect the coating thickness of Ni-Co alloy coatings.

Sintering of nickel catalysts. Effects of time, atmosphere, temperature, nickel-carrier interactions, and dopants

Energy Technology Data Exchange (ETDEWEB)

Sehested, Jens; Gelten, Johannes A.P.; Helveg, Stig [Haldor Topsoee A/S, Nymoellevej 55, DK-2800 Kgs. Lyngby (Denmark)

2006-08-01

Supported nickel catalysts are widely used in the steam-reforming process for industrial scale production of hydrogen and synthesis gas. This paper provides a study of sintering in nickel-based catalysts (Ni/Al{sub 2}O{sub 3} and Ni/MgAl{sub 2}O{sub 4}). Specifically the influence of time, temperature, atmosphere, nickel-carrier interactions and dopants on the rate of sintering is considered. To probe the sintering kinetics, all catalysts were analyzed by sulfur chemisorption to determine the Ni surface area. Furthermore selected samples were further analyzed using X-ray diffraction (XRD), mercury porosimetry, BET area measurements, and electron microscopy (EM). The observed sintering rates as a function of time, temperature, and P{sub H{sub 2}O}/P{sub H{sub 2}} ratio were consistent with recent model predictions [J. Sehested, J.A.P. Gelten, I.N. Remediakis, H. Bengaard, J.K. Norskov, J. Catal. 223 (2004) 432] over a broad range of environmental conditions. However, exposing the catalysts to severe sintering conditions the loss of nickel surface area is faster than model predictions and the deviation is attributed to a change in the sintering mechanism and nickel removal by nickel-carrier interactions. Surprisingly, alumina-supported Ni particles grow to sizes larger than the particle size of the carrier indicating that the pore diameter does not represent an upper limit for Ni particle growth. The effects of potassium promotion and sulfur poisoning on the rates of sintering were also investigated. No significant effects of the dopants were observed after ageing at ambient pressure. However, at high pressures of steam and hydrogen (31bar and H{sub 2}O:H{sub 2}=10:1) potassium promotion increased the sintering rate relative to that of the unpromoted catalyst. Sulfur also enhances the rate of sintering at high pressures, but the effect of sulfur is less than for potassium. (author)

Influences of magnetic field on the fractal morphology in copper electrodeposition

Science.gov (United States)

Sudibyo; How, M. B.; Aziz, N.

2018-01-01

Copper magneto-electrodeposition (MED) is used decrease roughening in the copper electrodeposition process. This technology plays a vital role in electrodeposition process to synthesize metal alloy, thin film, multilayer, nanowires, multilayer nanowires, dot array and nano contacts. The effects of magnetic fields on copper electrodeposition are investigated in terms of variations in the magnetic field strength and the electrolyte concentration. Based on the experimental results, the mere presence of magnetic field would result in a compact deposit. As the magnetic field strength is increased, the deposit grows denser. The increment in concentration also leads to the increase the deposited size. The SEM image analysis showed that the magnetic field has a significant effect on the surface morphology of electrodeposits.

Hierarchical mesoporous graphene@Ni-Co-S arrays on nickel foam for high-performance supercapacitors

International Nuclear Information System (INIS)

Nguyen, Van Hoa; Lamiel, Charmaine; Shim, Jae-Jin

2015-01-01

Highlights: • Hierarchical mesoporous graphene@Ni-Co-S arays have been decorated on Ni foam. • The electrode exhibits a high specific capacitance of 9.2 F cm −1 at 100 mA cm −1 . • The electrode presents large electroactive surface area and excellent structural stability. - Abstract: Hierarchical mesoporous graphene and ternary nickel cobalt sulfide (Ni-Co-S) arrays on nickel foam were designed and fabricated by chemical vapor deposition and electrodeposition for supercapacitor applications. The electrodes exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability owing to the highly conductive, mesoporous nature of graphene and the Ni-Co-S nanosheets, as well as to the open framework of the three-dimensional nanoarchitectures. The specific capacitance of the obtained electrode was as high as 9.2 F cm −1 at a high current density of 100 mA cm −1 , indicating promising applications as an efficient electrode for electrochemical capacitors

Cytotoxic effects of nickel nanowires in human fibroblasts

KAUST Repository

Felix Servin, Laura P.

2016-03-09

The increasing interest in the use of magnetic nanostructures for biomedical applications necessitates rigorous studies to be carried out in order to determine their potential toxicity. This work attempts to elucidate the cytotoxic effects of nickel nanowires (NWs) in human fibroblasts WI-38 by a colorimetric assay (MTT) under two different parameters: NW concentration and exposure time. This was complemented with TEM and confocal images to assess the NWs internalization and to identify any changes in the cell morphology. Ni NWs were fabricated by electrodeposition using porous alumina templates. Energy dispersive X-Ray analysis, scanning electron microscopy and transmission electron microscopy imaging were used for NW characterization. The results showed decreased cell metabolic activity for incubation times longer than 24 hours and no negative effects for exposure times shorter than that. The cytotoxicity effects for human fibroblasts were then compared with those reported for HCT 116 cells, and the findings point out that it is relevant to consider the cellular size. In addition, the present study compares the toxic effects of equivalent amounts of nickel in the form of its salt to those of NWs and shows that the NWs are more toxic than the salts. Internalized NWs were found in vesicles inside of the cells where their presence induced inflammation of the endoplasmic reticulum.

Cryoforming evaluation using high-purity nickel

International Nuclear Information System (INIS)

Lord, D.E.; Meisner, L.F.

1976-01-01

The cryogenic forming process was evaluated using nickel 270 to see if it had significant advantages over room-temperature (RT) forming. Typically, the procedure involved fast-strain-rate forming a set of nickel samples at cryogenic temperatures and another set at RT. Both sets were measured at RT for failure strength and their strength-preparation elongation curves compared at equal strains. Two more sets were formed, this time at slow strain rates (one at cryogenic temperatures, the other at RT). Both sets were measured at RT for failure strength and their strength-preparation elongation curves of these sets compared with the previous two at equal temperatures and strains. Cryoforming produced a 30 percent higher-strength nickel than that produced at room temperature at equal strains and strain rates. Forming rate effects disappeared as working temperature decreased. Rate-insensitive cryoforming produced a considerably stronger room-temperature material than room-temperature forming at high strain rates. Transmission electron microscopy indicated apparent structural differences between cryoformed and room-temperature-formed nickel. 14 fig

Effect of electrodeposition current density on the microstructure and the degradation of electroformed iron for degradable stents

Energy Technology Data Exchange (ETDEWEB)

Moravej, Maryam [Laboratory for Biomaterials and Bioengineering, Department of Mining, Metallurgy and Materials Engineering and University Hospital Research Center, Universite Laval, Quebec City, Que. G1V 0A6 (Canada); Department of Mining, Metallurgy and Materials Engineering, Pavillon Adrien-Pouliot, 1065 avenue de la Medecine, Local 1745-E, Universite Laval, Quebec City, Que. G1V 0A6 (Canada); Amira, Sofiene [Aluminium Technology Centre, Industrial Materials Institute, National Research Council Canada, 501, boul. de l' Universite Est, Saguenay, Que. G7H 8C3 (Canada); Prima, Frederic [Laboratory for Physical Metallurgy, Ecole Nationale Superieure de Chimie de Paris, Universite Pierre et Marie Curie, Paris 6 (France); Rahem, Ahmed [Aluminium Technology Centre, Industrial Materials Institute, National Research Council Canada, 501, boul. de l' Universite Est, Saguenay, Que. G7H 8C3 (Canada); Fiset, Michel [Department of Mining, Metallurgy and Materials Engineering, Pavillon Adrien-Pouliot, 1065 avenue de la Medecine, Local 1745-E, Universite Laval, Quebec City, Que. G1V 0A6 (Canada); and others

2011-12-15

Pure iron has become one of the most interesting candidate materials for degradable metallic stents due to its high mechanical properties and moderate degradation. In this work we studied the effect of electrodeposition current density on microstructure and degradation of pure iron films electrodeposited on Ti alloy substrate for degradable metallic stent application. Iron sheets were produced by electrodeposition using four different current densities 1, 2, 5 and 10 A dm{sup -2}. The films were then studied by SEM (scanning electron microscope) and EBSD (electron backscatter diffraction) to observe the surface morphology, grain size and orientation. Potentiodynamic polarization and static immersion tests were used to determine the corrosion rate and to study the degradation behavior of iron films, respectively. The current density was found to significantly influence the texture, the grain size and the grain shape of the electrodeposited iron. At current densities of 1, 5 and 10 A dm{sup -2}, weak textures corresponding to Left-Pointing-Angle-Bracket 1 0 1 Right-Pointing-Angle-Bracket , Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket and Left-Pointing-Angle-Bracket 1 1 2 Right-Pointing-Angle-Bracket in the normal (electrodeposition) direction were obtained, respectively. At these current densities, average grain sizes smaller than 3 {mu}m were also obtained. However, at 2 A dm{sup -2}, a strong Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket //ND texture with density of 7.4 MUD was obtained with larger average grain size of 4.4 {mu}m. The microstructure of iron samples changed after annealing at 550 Degree-Sign C because of the induced recrystallization. Different corrosion rates were obtained from potentiodynamic polarization curves of iron films deposited at different current densities because of their microstructures. Fe-2 showed the lowest corrosion rate due to its larger grains size and its texture. The corrosion rates of all

Long Silver Nanowires Synthesis by Pulsed Electrodeposition

Directory of Open Access Journals (Sweden)

M.R. Batevandi

2015-09-01

Full Text Available Silver nanowires were pulse electrodeposited into nanopore anodic alumina oxide templates. The effects of continuous and pulse electrodeposition waveform on the microstructure properties of the nanowire arrays were studied. It is seen that the microstructure of nanowire is depend to pulse condition. The off time duration of pulse waveform enables to control the growth direction of Ag nanowires.

Nickel and cobalt bimetallic hydroxide catalysts for urea electro-oxidation

International Nuclear Information System (INIS)

Yan Wei; Wang Dan; Botte, Gerardine G.

2012-01-01

Nickel–Cobalt bimetallic hydroxide electrocatalysts, synthesized through a one-step electrodeposition method, were evaluated for the oxidation of urea in alkaline conditions with the intention of reducing the oxidation overpotential for this reaction. The Nickel–Cobalt bimetallic hydroxide catalysts were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), Raman spectroscopy, cyclic voltammetry (CV), and polarization techniques. A significant reduction in the overpotential (150 mV) of the reaction was observed with the Nickel–Cobalt bimetallic hydroxide electrode (ca. 43% Co content) when compared to a nickel hydroxide electrode. The decrease of the urea oxidation potential on the Nickel–Cobalt bimetallic hydroxide electrodes reveals great potential for future applications of urea electro-oxidation, including wastewater remediation, hydrogen production, sensors, and fuel cells.

Method of recovering phosphoric acid type decontaminating electrolytes by electrodeposition

International Nuclear Information System (INIS)

Sasaki, Takashi; Wada, Koichi; Kobayashi, Toshio.

1985-01-01

Purpose: To recoving phosphoric acid type highly concentrated decontaminating liquid used for the electrolytic decontamination of contaminated equipments, components, etc in nuclear power plants or the like through electrodeposition by diaphragm electrolysis. Method: Before supplying phosphoric acid decontaminating liquid at high concentration used in the electrolytic decontaminating step to an electrodeposition recovering tank, phosphoric acid in the decontaminating electrolyte is extracted with solvents and decomposed liquid extracts (electrolyte reduced with the phosphoric acid component) are supplied to the cathode chamber of the electrodeposition recovering tank, where phosphoric acid is back-extracted with water from the solvents after extraction of phosphoric acid. Then, the back-extracted liquids (aqueous phosphoric acid solution scarcely containing metal ions) are sent to the anode chamber of the electrodeposition recovering tank. Metal ions in the liquid are captured by electrodeposition in the cathode chamber, as well as phosphoric acid in the liquids is concentrated to the initial concentration of the electrolyte in the anode chamber for reuse as the decontaminating electrolyte. As the phosphoric acid extracting agent used in the electrodeposition recovering step for the decontaminating electrolyte, water-insoluble and non-combustible tributyl phosphate (TBP) is most effective. (Horiuchi, T.)

Corrosion behavior of electrodeposited Co-Fe alloys in aerated solutions

Energy Technology Data Exchange (ETDEWEB)

Chansena, A. [Research Unit on Corrosion, College of Data Storage Innovation, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Sutthiruangwong, S., E-mail: sutha.su@kmitl.ac.th [Department of Chemistry, Faculty of Science, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Research Unit on Corrosion, College of Data Storage Innovation, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand)

2017-05-01

Co-Fe alloy is an important component for reader-writer in hard disk drive. The surface of the alloy is exposed to the environment both in gas phase and in liquid phase during manufacturing process. The study of corrosion behavior of Co-Fe alloys can provide useful fundamental data for reader-writer production planning especially when corrosion becomes a major problem. The corrosion study of electrodeposited Co-Fe alloys from cyclic galvanodynamic polarization was performed using potentiodynamic polarization technique. The composition of electrodeposited Co-Fe alloys was determined by X-ray fluorescence spectrometry. The patterns from X-ray diffractometer showed that the crystal structure of electrodeposited Co-Fe alloys was body-centered cubic. A vibrating sample magnetometer was used for magnetic measurements. The saturation magnetization (M{sub s}) was increased and the intrinsic coercivity (H{sub ci}) was decreased with increasing Fe content. The corrosion rate study was performed in aerated deionized water and aerated acidic solutions at pH 3, 4 and 5. The corrosion rate diagram for Co-Fe alloys was constructed. It was found that the corrosion rate of Co-Fe alloys was increased with increasing Fe content in both aerated deionized water and aerated acidic solutions. In aerated pH 3 solution, the Co-Fe alloy containing 78.8% Fe showed the highest corrosion rate of 7.7 mm yr{sup −1} with the highest M{sub s} of 32.0 A m{sup 2} kg{sup −1}. The corrosion rate of the alloy with 23.8% Fe was at 1.1 mm yr{sup −1} with M{sub s} of 1.2 A m{sup 2} kg{sup −1}. In aerated deionized water, the alloy with the highest Fe content of 78.5% still showed the highest corrosion rate of 0.0059 mm yr{sup −1} while the alloy with the lowest Fe content of 20.4% gave the lowest corrosion rate of 0.0045 mm yr{sup −1}. - Highlights: • The aeration during corrosion measurement simulates reader-writer head production environment. • The corrosion rate diagram for Co-Fe alloys

Synthesis of tin oxide nanoparticle film by cathodic electrodeposition.

Science.gov (United States)

Kim, Seok; Lee, Hochun; Park, Chang Min; Jung, Yongju

2012-02-01

Three-dimensional SnO2 nanoparticle films were deposited onto a copper substrate by cathodic electrodeposition in a nitric acid solution. A new formation mechanism for SnO2 films is proposed based on the oxidation of Sn2+ ion to Sn4+ ion by NO+ ion and the hydrolysis of Sn4+. The particle size of SnO2 was controlled by deposition potential. The SnO2 showed excellent charge capacity (729 mAh/g) at a 0.2 C rate and high rate capability (460 mAh/g) at a 5 C rate.

Fabrication of Nickel/nanodiamond/boron-doped diamond electrode for non-enzymatic glucose biosensor

International Nuclear Information System (INIS)

Dai, Wei; Li, Mingji; Gao, Sumei; Li, Hongji; Li, Cuiping; Xu, Sheng; Wu, Xiaoguo; Yang, Baohe

2016-01-01

Highlights: • Nanodiamonds (NDs) were electrophoretically deposited on the BDD film. • The NDs significantly extended the potential window. • Ni/NDs/BDD electrode was prepared by electrodeposition. • The electrode shows good catalytic activity for glucose oxidation. - Abstract: A stable and sensitive non-enzymatic glucose sensor was prepared by modifying a boron-doped diamond (BDD) electrode with nickel (Ni) nanosheets and nanodiamonds (NDs). The NDs were electrophoretically deposited on the BDD surface, and acted as nucleation sites for the subsequent electrodeposition of Ni. The morphology and composition of the modified BDD electrodes were characterized by field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The Ni nanosheet-ND modified BDD electrode exhibited good current response towards the non-enzymatic oxidation of glucose in alkaline media. The NDs significantly extended the potential window. The response to glucose was linear over the 0.2–1055.4-μM range. The limit of detection was 0.05 μM, at a signal-to-noise ratio of 3. The Ni nanosheet-ND/BDD electrode exhibited good selectivity, reproducibility and stability. Its electrochemical performance, low cost and simple preparation make it a promising non-enzymatic glucose sensor.

Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

KAUST Repository

Lu, Yingying; Tu, Zhengyuan; Archer, Lynden A.

2014-01-01

of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid

Effect of pulse frequency and current density on anomalous composition and nanomechanical property of electrodeposited Ni-Co films

Energy Technology Data Exchange (ETDEWEB)

Chung, C.K., E-mail: ckchung@mail.ncku.edu.t [Department of Mechanical Engineering, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan 701 (China); Chang, W.T. [Department of Mechanical Engineering, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan 701 (China)

2009-07-01

Effect of pulse frequency and current density on the anomalous cobalt content and nanomechanical property of the electrodeposited nickel-cobalt (Ni-Co) films has been investigated. The composition, morphology, phase and hardness of the Ni-Co alloy films were examined by scanning electron microscope with an attached energy dispersive X-ray spectroscope, X-ray diffraction and nanoindentation techniques, respectively. The different Co composition of the Ni-Co films codeposited from the fixed sulfamate-chloride bath is subject to the pulse frequencies and current densities. The frequencies varied from 0 to 100 Hz and current densities varied from 1 to 20 ASD (ampere per square decimeter). The Co composition has no significant variation in pulse electrodeposition but it is greatly influenced by current densities from 22.53% at 1 ASD decreased to 13.39% at 20 ASD under DC codeposition. The mean hardness of Ni-Co films has no eminent change at a pulse frequency of 10-100 Hz but it decreases with current densities from 8.72 GPa (1 ASD) to 7.13 GPa (20 ASD). The smoother morphology can be obtained at higher pulse frequency or lower current density. Good Ni-Co films with high hardness and smooth morphology can be obtained by reducing current density and increasing pulse frequency.

Niobium electrodeposition from molten fluorides

International Nuclear Information System (INIS)

Sartori, A.F.

1987-01-01

Niobium electrodeposition from molten alkali fluorides has been studied aiming the application of this technic to the processes of electrorefining and galvanotechnic of this metal. The effects of current density, temperature, niobium concentration in the bath, electrolysis time, substrate nature, ratio between anodic and cathodic areas, electrodes separation and the purity of anodes were investigated in relation to the cathodic current efficiency, electrorefining, electroplating and properties of the deposit and the electrolytic solution. The work also gives the results of the conctruction and operation of a pilot plant for refractory metals electrodeposition and shows the electrorefining and electroplating compared to those obtained at the laboratory scale. (author) [pt

Preliminary results about Electrodeposition of Cobalt at laboratory level

International Nuclear Information System (INIS)

Cornejo, N.

1992-01-01

As of an organic compound, an extraction and Cobalt electrodeposition method had been developed as a part of fabrication aim of a sealed radioactive source with objective to the construction of density meter prototype. It was performed preliminary test of electrodeposition in the laboratory level in a simple cell. The used electrolyte had been a sulphate solution obtained by extraction of an organic solution. It is obtained a Co film by electrodeposition at 55 o C temperature and with an approximately Co concentration in 70 g/lt. (Author) 3 refs., 1 fig., 1 tab

Characterisation of electrodeposited and heat-treated Ni-Mo-P coatings

Energy Technology Data Exchange (ETDEWEB)

Melo, Regis L.; Casciano, Paulo N.S.; Correia, Adriana N.; Lima-Neto, Pedro de, E-mail: pln@ufc.br [Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, Fortaleza, CE (Brazil)

2012-07-01

The electrodeposition, hardness and corrosion resistance properties of Ni-Mo-P coatings were investigated. Characterisations of the electrodeposited coatings were carried out using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis techniques. Corrosion tests were performed at room temperature in 10-1 mol dm-3 NaCl solutions and by potentiodynamic linear polarisation. Amorphous Ni-Mo-P coatings were successfully obtained by electrodeposition using direct current. The coating composition showed to be dependent on the bath composition, current density and bath temperature. Both P and Mo contents contribute for the hardness properties of the Ni-Mo-P coatings and the absence of cracks is a requirement to produce electrodeposited Ni-Mo-P coatings with good hardness properties. The hardness values increase with heat-treatment temperature due to the precipitation of Ni, Ni{sub 3}P and NiMo phases during the heat treatment. The corrosion resistance of the electrodeposited Ni-Mo-P amorphous coatings increases with P content in the layer. Among the electrodeposited Ni-Mo-P amorphous coatings, Ni{sub 78}Mo{sub 10}P{sub 12} presented the best hardness and corrosion-resistance properties. The results showed that the addition of P is beneficial for the hardness and corrosion resistance properties of the Ni-Mo-based coatings. (author)

Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes

NARCIS (Netherlands)

Maijenburg, A.W.

2014-01-01

This thesis is entitled “Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes”. Templated electrodeposition is the synthesis technique that was used throughout this thesis, and it comprises the use of a template with specific shape and dimensions for the

Urine nickel concentrations in nickel-exposed workers.

Science.gov (United States)

Bernacki, E J; Parsons, G E; Roy, B R; Mikac-Devic, M; Kennedy, C D; Sunderman, F W

1978-01-01

Electrothermal atomic absorption spectrometry was employed for analyses of nickel concentrations in urine samples from nickel-exposed workers in 10 occupational groups and from non-exposed workers in two control groups. Mean concentrations of nickel in urine were greatest in workers who were exposed to inhalation of aerosols of soluble nickel salts (e.g., workers in nickel plating operations and in an electrolytic nickel refinery). Less marked increases in urine nickel concentrations were found in groups of metal sprayers, nickel battery workers, bench mechanics and are welders. No significant increases in mean concentrations of nickel were found in urine samples from workers who performed grinding, buffing and polishing of nickel-containing alloys or workers in a coal gasification plant who employed Raney nickel as a hydrogenation catalyst. Measurements of nickel concentrations in urine are more sensitive and practical than measurements of serum nickel concentrations for evaluation of nickel exposures in industrial workers.

Synthesis of shape memory alloys using electrodeposition

Science.gov (United States)

Hymer, Timothy Roy

Shape memory alloys are used in a variety of applications. The area of micro-electro-mechanical systems (MEMS) is a developing field for thin film shape memory alloys for making actuators, valves and pumps. Until recently thin film shape memory alloys could only be made by rapid solidification or sputtering techniques which have the disadvantage of being "line of sight". At the University of Missouri-Rolla, electrolytic techniques have been developed that allow the production of shape memory alloys in thin film form. The advantages of this techniques are in-situ, non "line of sight" and the ability to make differing properties of the shape memory alloys from one bath. This research focused on the electrodeposition of In-Cd shape memory alloys. The primary objective was to characterize the electrodeposited shape memory effect for an electrodeposited shape memory alloy. The effect of various operating parameters such as peak current density, temperature, pulsing, substrate and agitation were investigated and discussed. The electrodeposited alloys were characterized by relative shape memory effect, phase transformation, morphology and phases present. Further tests were performed to optimize the shape memory by the use of a statistically designed experiment. An optimized shape memory effect for an In-Cd alloy is reported for the conditions of the experiments.

Electrodeposition of Metal on GaAs Nanowires

Science.gov (United States)

Liu, Chao; Einabad, Omid; Watkins, Simon; Kavanagh, Karen

2010-10-01

Copper (Cu) electrical contacts to freestanding gallium arsenide (GaAs) nanowires have been fabricated via electrodeposition. The nanowires are zincblende (111) oriented grown epitaxially on n-type Si-doped GaAs (111)B substrates by gold-catalyzed Vapor Liquid Solid (VLS) growth in a metal organic vapour phase epitaxy (MOVPE) reactor. The epitaxial electrodeposition process, based on previous work with bulk GaAs substrates, consists of a substrate oxide pre-etch in dilute ammonium-hydroxide carried out prior to galvanostatic electrodeposition in a pure Cu sulphate aqueous electrolyte at 20-60^oC. For GaAs nanowires, we find that Cu or Fe has a preference for growth on the gold catalyst avoiding the sidewalls. After removing gold, both metals still prefer to grow only on top of the nanowire, which has the largest potential field.

Effect of surfactant concentration in the electrolyte on the tribological properties of nickel-tungsten carbide composite coatings produced by pulse electro co-deposition

Science.gov (United States)

Kartal, Muhammet; Uysal, Mehmet; Gul, Harun; Alp, Ahmet; Akbulut, Hatem

2015-11-01

A nickel plating bath containing WC particles was used to obtain hard and wear-resistant particle reinforced Ni/WC MMCs on steel surfaces for anti-wear applications. Copper substrates were used for electro co-deposition of Ni matrix/WC with the particle size of <1 μm tungsten carbide reinforcements. The influence of surfactant (sodium dodecyl sulfate, SDS) concentration on particle distribution, microhardness and wear resistance of composite coatings has been studied. The nickel films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of the surfactant on the zeta potential, co-deposition and distribution of WC particles in the nickel matrix, as well as the tribological properties of composite coatings were also investigated. The tribological behaviors of the electrodeposited WC composite coatings sliding against M50 steel ball (Ø 10 mm) were examined on a CSM Instrument. All friction and wear tests were performed without lubrication at room temperature and in the ambient air (relative humidity 55-65%).

Kinetic features of cadmium electrodeposition in iodide water-acetone electrolytes

International Nuclear Information System (INIS)

Kuznetsov, V.V.; Skibina, L.M.; Khalikov, R.R.

2006-01-01

Based on the data of chronopotentiometric, galvanostatic, potentiodynamic, and impedance measurements, the composition of aqueous acetone electrolyte is studied for its effect on the rate of cadmium(II) electroreduction in iodide media. The adsorption of I - ions on the cadmium cathode surface is shown to depend on the interaction mechanism between the components of water-acetone mixtures. During a competitive adsorption of anions and organic solvent molecules, this affects the mechanism and the rate of electrodeposition and also the coating quality [ru

Electrodeposition of Ni-W Alloy and Characterization of Microstructure and Properties of the Deposits

DEFF Research Database (Denmark)

Mizushima, Io

2007-01-01

of the electrolyte. Simultaneously, the presence of carbon is observed with GDOES in layers deposited from the aged electrolyte. The carbon dissolution in the Ni-W alloy deposit is associated with the formation of a new phase in the electrodeposit, giving rise to the anomalous Bragg peak. In Chapter 8 hardness....... The experimental results of the present work are given in the chapters 4-9. In Chapter 4 development of a new electrolyte for Ni-W alloys is described. In the chapters 5-9 the properties of the Ni-W alloys such as residual stress, microstructure, hardness and thermal stability are investigated. Furthermore......, grain size and thermal stability of nickel and Ni-W alloy layers deposited from electrolytes containing equal amounts of citrate, glycine and triethanolamine are investigated. The hardness of the deposits was investigated in the as-deposited layer as well as after annealing for 1 hour at temperatures up...

Electrodeposition: Principles, Applications and Methods

International Nuclear Information System (INIS)

Nur Ubaidah Saidin; Ying, K.K.; Khuan, N.I.

2011-01-01

Electrodeposition technique has been around for a very long time. It is a process of coating a thin layer of one metal on top of a different metal to modify its surface properties, by donating electrons to the ions in a solution. This bottom-up fabrication technique is versatile and can be applied to a wide range of potential applications. Electrodeposition is gaining popularity in recent years due to its capability in fabricating one-dimensional nano structures such as nano rods, nao wires and nano tubes. In this paper, we present an overview on the fabrication and characterization of high aspect ratio nano structures prepared using the nano electrochemical deposition system set up in our laboratory. (author)

Influence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) on zinc electrodeposition

International Nuclear Information System (INIS)

Lehr, I.L.; Saidman, S.B.

2012-01-01

This work is a study of the electrodeposition of zinc onto SAE 4140 steel electrodes using solutions containing zinc sulfate and bis(2-ethylhexyl) sodium sulfosuccinate (AOT). The influence of different parameters such as electrolyte concentration, electrodeposition time and temperature on the morphology of the electrodeposits was analyzed. The deposits were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction. The variation of open circuit potential over time in chloride solutions was also evaluated. The nucleation-growth process and consequently the morphology of the electrodeposits are modified in the presence of AOT. The surfactant induces the formation of a porous deposit.

Influence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) on zinc electrodeposition

Science.gov (United States)

Lehr, I. L.; Saidman, S. B.

2012-03-01

This work is a study of the electrodeposition of zinc onto SAE 4140 steel electrodes using solutions containing zinc sulfate and bis(2-ethylhexyl) sodium sulfosuccinate (AOT). The influence of different parameters such as electrolyte concentration, electrodeposition time and temperature on the morphology of the electrodeposits was analyzed. The deposits were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction. The variation of open circuit potential over time in chloride solutions was also evaluated. The nucleation-growth process and consequently the morphology of the electrodeposits are modified in the presence of AOT. The surfactant induces the formation of a porous deposit.

Electroplated tin-nickel coatings as a replacement for nickel to eliminate nickel dermatitis

DEFF Research Database (Denmark)

Møller, Per; Boyce, Jan M.; Nielsen, Lars Pleth

2013-01-01

. The main focus will be on the corrosion properties where the following corrosion investigations will be covered; corrosion potential measurements for the different coatings, estimation of corrosion rates for materials in galvanic coupling with tin/nickel coatings, salt spray test, medical tests...

Electroless nickel plating on abs plastics from nickel chloride and nickel sulfate baths

International Nuclear Information System (INIS)

Inam-ul-haque; Ahmad, S.; Khan, A.

2005-01-01

Aqueous acid nickel chloride and alkaline nickel sulphate bath were studied for electroless nickel planting on acrylonitrile-butadiene-styrene (ABS) plastic. Before electroless nickel plating, specimens were etched, sensitized and activated. Effects of sodium hypophosphite and sodium citrate concentration on the electroless nickel plating thickness were discussed. Aqueous acid nickel chloride bath comprising, nickel chloride 10 g/L, sodium hypophosphite 40 g/L, sodium citrate 40g/L at pH 5.5, temperature 85 deg. C and density of 1 Be/ for thirty minutes gave best coating thickness in micrometer. It was found that acid nickel chloride bath had a greater stability, wide operating range and better coating thickness results than alkaline nickel sulphate bath. Acid nickel chloride bath gave better coating thickness than alkaline nickel sulfate bath

Conductance quantization in magnetic nanowires electrodeposited in nanopores

DEFF Research Database (Denmark)

Elhoussine, F.; Mátéfi-Tempfli, Stefan; Encinas, A.

2002-01-01

Magnetic nanocontacts have been prepared by a templating method that involves the electrodeposition of Ni within the pores of track-etched polymer membranes. The nanocontacts are made at the extremity of a single Ni nanowire either inside or outside the pores. The method is simple, flexible...... degeneracy. Our fabrication method enables future investigation of ballistic spin transport phenomena in electrodeposited magnetic nanocontacts....

Cathodic electrodeposition of ceramic and organoceramic materials. Fundamental aspects.

Science.gov (United States)

Zhitomirsky, I

2002-03-29

Electrodeposition of ceramic materials can be performed by electrophoretic (EPD) or electrolytic (ELD) deposition. Electrophoretic deposition is achieved via motion of charged particles towards an electrode under an applied electric field. Electrolytic deposition produces colloidal particles in cathodic reactions for subsequent deposition. Various electrochemical strategies and deposition mechanisms have been developed for electrodeposition of ceramic and organoceramic films, and are discussed in the present article. Electrode-position of ceramic and organoceramic materials includes mass transport, accumulation of particles near the electrode and their coagulation to form a cathodic deposit. Various types of interparticle forces that govern colloidal stability in the absence and presence of processing additives are discussed. Novel theoretical contributions towards an interpretation of particle coagulation near the electrode surface are reviewed. Background information is given on the methods of particle charging, stabilization of colloids in aqueous and non-aqueous media, electrophoretic mobility of ceramic particles and polyelectrolytes, and electrode reactions. This review also covers recent developments in the electrodeposition of ceramic and organoceramic materials.

Electrodeposition and surface finishing fundamentals and applications

CERN Document Server

Djokic, Stojan

2014-01-01

This volume of Modern Aspects of Electrochemistry has contributions from significant individuals in electrochemistry. This 7 chapter book discusses electrodeposition and the characterization of alloys and composite materials, the mechanistic aspects of lead electrodeposition, electrophoretic deposition of ceramic materials onto metal surfaces and the fundamentals of metal oxides for energy conversion and storage technologies. This volume also has a chapter devoted to the anodization of aluminum, electrochemical aspects of chemical and mechanical polishing, and surface treatments prior to metal

Material reliability of Ni alloy electrodeposition for steam generator tube repair

International Nuclear Information System (INIS)

Kim, Dong Jin; Kim, Myong Jin; Kim, Joung Soo; Kim, Hong Pyo

2007-01-01

Due to the occasional occurrences of Stress Corrosion Cracking (SCC) in steam generator tubing (Alloy 600), degraded tubes are removed from service by plugging or are repaired for re-use. Since electrodeposition inside a tube dose not entail parent tube deformation, residual stress in the tube can be minimized. In this work, tube restoration via electrodeposition inside a steam generator tubing was performed after developing the following: an anode probe to be installed inside a tube, a degreasing condition to remove dirt and grease, an activation condition for surface oxide elimination, a tightly adhered strike layer forming condition between the electroforming layer and the Alloy 600 tube, and the condition for an electroforming layer. The reliability of the electrodeposited material, with a variation of material properties, was evaluated as a function of the electrodeposit position in the vertical direction of a tube using the developed anode. It has been noted that the variation of the material properties along the electrodeposit length was acceptable in a process margin. To improve the reliability of a material property, the causes of the variation occurrence were presumed, and an attempt to minimize the variation has been made. A Ni alloy electrodeposition process is suggested as a Primary Water Stress Corrosion Cracking (PWSCC) mitigation method for various components, including steam generator tubes. The Ni alloy electrodeposit formed inside a tube by using the installed assembly shows proper material properties as well as an excellent SCC resistance

Electrodeposited Silver Nanoparticles Patterned Hexagonally for SERS

International Nuclear Information System (INIS)

Gu, Geun Hoi; Lee, Sue Yeone; Suh, Jung Sang

2010-01-01

We have fabricated hexagonally patterned silver nanoparticles for surface-enhanced Raman scattering (SERS) by electrodepositing silver on the surface of an aluminum plate prepared by completely removing the oxide from anodic aluminum oxide (AAO) templates. Even after completely removing the oxide, well-ordered hexagonal patterns, similar to the shape of graphene, remained on the surface of the aluminum plate. The borders of the hexagonal pattern protruded up to form sorts of nano-mountains at both the sides and apexes of the hexagon, with the apexes protruding even more significantly than the sides. The aluminum plate prepared by completely removing the oxide has been used in the preparation of SERS substrates by sputter-coating of gold or silver on it. Instead of sputter-coating, here we have electro-deposited silver on the aluminum plate. When silver was electro-deposited on the plate, silver nanoparticles were made along the hexagonal margins.

Interpretation of microstructure evolution during self-annealing and thermal annealing of nanocrystalline electrodeposits—A comparative study

DEFF Research Database (Denmark)

Pantleon, Karen; Somers, Marcel A. J.

2010-01-01

and nickel electrodeposits was achieved by time-resolved X-ray diffraction line profile analysis and crystallographic texture analysis during room temperature storage and during isothermal annealing at elevated temperatures. These in-situ studies with unique time resolution allowed quantification of the self-annealing......Electrodeposition results in a non-equilibrium state of the as-deposited nanocrystalline microstructure, which evolves towards an energetically more favorable state as a function of time and/or temperature upon deposition. Real-time investigation of the evolving microstructure in copper, silver...... kinetics of copper and silver electrodeposits as well as the annealing kinetics of electrodeposited nickel. Similarities and characteristic differences of the kinetics and mechanisms of microstructure evolution in the various electrodeposits are discussed and the experimental results are attempted...

Nickel Dermatitis - Nickel Excretion

DEFF Research Database (Denmark)

Menné, T.; Thorboe, A.

1976-01-01

Nickel excretion in urine in four females -sensitive to nickel with an intermittent dyshidrotic eruption was measured with flameless atomic absorption. Excretion of nickel was found to be increased in association with outbreaks of vesicles. The results support the idea that the chronic condition ...

Magnetic properties of CoP alloys electrodeposited at room temperature

International Nuclear Information System (INIS)

Lucas, I.; Perez, L.; Aroca, C.; Sanchez, P.; Lopez, E.; Sanchez, M.C.

2005-01-01

CoP alloys have been electrodeposited at room temperature from electrolytes with different pH values and their magnetic properties have been studied. Cracks and fractures appear when using stiff substrates, showing that high internal stresses, due to hydrogen evolution, are involved in the electrodeposition process. Samples electrodeposited onto flexible substrates do not show cracks on the surface. We also report an increment in the coercivity of the alloys when the pH of the electrolyte decreases, and therefore, the hydrogen evolution and the internal stresses increase

The mechanism of electrodeposition of bismuth sulfide and cadmium sulfide from dimethylsulfoxide and diethylene glycol solution

International Nuclear Information System (INIS)

Gilbert, C.M.; Baranski, A.S.; Fawcett, W.R.

1985-01-01

The kinetics of the electrodeposition of Bi 2 S 3 on an electrode covered with a coherent layer of Bi 2 S 3 was examined by analysis of the Tafel plots for different solution compositions and at different temperatures in two nonaqueous solvents, dimethylsulfoxide (DMSO) and diethylene glycol (DEG). The results were compared with those obtained for the electrodeposition of CdS on CdS under similar conditions. In both cases, it was found that the rate-determining step was an irreversible electron transfer. The rate of the reaction was independent of the metal ion concentration, but electrochemical orders with respect to S 8 of 0.7 in DMSO and 1.0 in DEG were found. Several mechanisms explaining these results are proposed and discussed

Hydrogen-water deuterium exchange over metal oxide promoted nickel catalysts

Energy Technology Data Exchange (ETDEWEB)

Sagert, N H; Shaw-Wood, P E; Pouteau, R M.L. [Atomic Energy of Canada Ltd., Pinawa, Manitoba. Whiteshell Nuclear Research Establishment

1975-11-01

Specific rates have been measured for hydrogen-water deuterium isotope exchange over unsupported nickel promoted with about 20% of various metal oxides. The oxides used were Cr/sub 2/O/sub 3/, MoO/sub 2/, MnO, WO/sub 2/-WO/sub 3/, and UO/sub 2/. Nickel surface areas, which are required to measure the specific rates, were determined by hydrogen chemisorption. Specific rates were measured as a function of temperature in the range 353 to 573 K and as a function of the partial pressure of hydrogen and water over a 10-fold range of partial pressure. The molybdenum and tungsten oxides gave the highest specific rates, and manganese and uranium oxides the lowest. Chromium oxide was intermediate, although it gave the highest rate per gram of catalyst. The orders with respect to hydrogen and water over molybdenum oxide and tungsten oxide promoted nickel were consistent with a mechanism in which nickel oxide is formed from the reaction of water with the catalyst, and then is reduced by hydrogen. Over manganese and uranium oxide promoted catalysts, these orders are consistent with a mechanism in which adsorbed water exchanges with chemisorbed hydrogen atoms on the nickel surface. Chromium oxide is intermediate. It was noted that those oxides which favored the nickel oxide route had electronic work functions closest to those of metallic nickel and nickel oxide.

Ni-Al phase transformation of dual layer coating prepared by pack cementation and electrodeposition

Science.gov (United States)

Afandi, A.; Sugiarti, E.; Ekaputra, R.; Sudiro, T.; Thosin, K. A. Z.

2018-03-01

In this work, Fe-Cr alloys were coated via Aluminum (Al) pack cementation, followed by Nickel (Ni) electrodeposition. The process of pack cementation was done with mixing powders of Al, Al203 and NH4Cl with weight percentage of 15%, 85%, and 5% respectively. To control successful Al diffusion to the substrate, pack cementation was conducted for 7 hours with two holding temperatures treatment at 400 °C for 4 hours, and 800 ° C hours for 2 hours. Subsequently, the electrodeposition of Ni was applied with the solution consisting of NiSO4, H3BO3, and NiCl2. The samples were placed in the cathode, and then dipped in the solutions, while Ni plate used as anode. Successfully the samples were coated by dual Al-Ni layers, the samples were slowly heat treated at 900 °C for 10 hours. The inter-diffusion of Al and Ni were characterized with SEM/EDX to investigate the distribution of the elements. Mechanical properties of the coated substrates were analyzed with Hardness Vickers (HV). It was found the hardness of the substrate increased significantly, from originally 255 HV to the 1177 HV after pack cementation. The hardness of the substrates has decreased to 641 HV after Ni plating, but subsequent heat treatment has been able to increase the hardness to 842 HV. This phenomenon can be correlated to the inward Al diffusion, and outward Fe, Cr diffusion. The formation of intermetallic compounds due to Al inward and Fe, Cr outward diffusion were discussed in details.

The template-assisted electrodeposition of platinum nanowires for catalytic applications

Directory of Open Access Journals (Sweden)

Soha Mohajeri

2018-05-01

Full Text Available Template-assisted electrodeposition technique was applied to synthesize platinum nanowires (Pt NWs on polycarbonate templates (PCT with pore diameters of 15, 50, and 100 nm for catalytic applications. Influences of sulfuric acid added to the electrolyte, different potential scanning rates and different pore diameters of templates on the electrodeposition process of Pt NWs were investigated by electrochemical techniques, including voltammetry and chronoamperometry methods. It was confirmed that at lower scan rates and in acidic solutions, electrodeposition of platinum on templates with larger pores is controlled by diffusion. The potential range for deposition of Pt NWs was determined and the potentiostatic technique was utilized by applying various potentials of different durations to fabricate the NWs. The morphological characteristics of Pt NWs were examined using the scanning electron microscopy (SEM. It was shown that the growth of Pt NWs on PCT 50 nm followed a pine-tree pattern, while the Pt NWs grew spherically on PCT 100 nm. The uniform and compact shape of Pt NWs was verified by the transmission electron microscopy (TEM. The catalytic activities of the prepared Pt NWs with the same exchanged charge density for hydrogen adsorption/desorption and methanol oxidation reactions were determined by the cyclic voltammetry (CV testing, and the superior electrocatalytic performance was detected for Pt NWs prepared on PCT 50 nm. This enhanced catalytic activity was attributed to the higher surface-to-volume ratio, larger electrochemical active surface area and higher density of exposed active sites accessible on the pine-tree morphology of these Pt NWs compared to the spherical structure of Pt NWs fabricated on PCT 100 nm. This makes Pt NWs prepared on PCT 50 nm to be a promising catalyst for direct methanol fuel cells (DMFCs.

Morphology of uranium electrodeposits on cathode in electrorefining process: A phase-field simulation

International Nuclear Information System (INIS)

Shibuta, Yasushi; Sato, Takumi; Suzuki, Toshio; Ohta, Hirokazu; Kurata, Masaki

2013-01-01

Morphology of uranium electrodeposits on cathode with respect to applied voltage, zirconium concentration in the molten salt and the size of primary deposit during pyroprocessing is systematically investigated by the phase-field simulation. It is found that there is a threshold zirconium concentration in the molten salt demarcating planar and cellular/needle-like electrodeposits, which agrees with experimental results. In addition, the effect of size of primary deposits on the morphology of electrodeposits is examined. It is then confirmed that cellular/needle-like electrodeposits are formed from large primary deposits at all applied voltages considered, whereas both the planar and cellular/needle-like electrodeposits are formed from the primary deposits of 10 μm and less

Effect of glycerin and formic acid in the efficiency of deposit on Zn-Ni, obtained by electrodeposition; Efeito da glicerina e do acido formico na eficiencia de deposito da liga Zn-Ni, obtido atraves de eletrodeposicao

Energy Technology Data Exchange (ETDEWEB)

Pedroza, G.A.G.; Souza, C.A.C.; Lima, L.R.P.A.; Ferreira, D.M. [Universidade Federal da Bahia - Escola Politecnica, BA (Brazil)

2010-07-01

Additives are added to the electrodeposition of metal coatings to improve the characteristics of the deposit. However, the objective was to investigate the effect of adding glycerin and formic acid in the deposition efficiency and deposit structure of zinc-nickel alloy obtained by electrodeposition. The depositions were made at a galvanostatic current density of 10 mA/cm{sup 2} to obtain a deposit of about 5 mm in thickness. The deposition efficiency was determined through measures of mass, chemical composition of the deposit in the presence and absence of additives was examined by X-ray Spectrometer Fluorescence (XRF) and surface characterization of coatings was performed by Scanning Electron Microscopy (SEM). The high levels of glycerin (0,07 M) and formic acid (0,26 M) in bath deposition increased the deposition efficiency of around 10% to 12% by mass, respectively. (author)

Flexible, silver nanowire network nickel hydroxide core-shell electrodes for supercapacitors

Science.gov (United States)

Yuksel, Recep; Coskun, Sahin; Kalay, Yunus Eren; Unalan, Husnu Emrah

2016-10-01

We present a novel one-dimensional coaxial architecture composed of silver nanowire (Ag NW) network core and nickel hydroxide (Ni(OH)2) shell for the realization of coaxial nanocomposite electrode materials for supercapacitors. Ag NWs are formed conductive networks via spray coating onto polyethylene terephthalate (PET) substrates and Ni(OH)2 is gradually electrodeposited onto the Ag NW network to fabricate core-shell electrodes for supercapacitors. Synergy of highly conductive Ag NWs and high capacitive Ni(OH)2 facilitate ion and electron transport, enhance electrochemical properties and result in a specific capacitance of 1165.2 F g-1 at a current density of 3 A g-1. After 3000 cycles, fabricated nanocomposite electrodes show 93% capacity retention. The rational design explored in this study points out the potential of nanowire based coaxial energy storage devices.

Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

KAUST Repository

Pasta, Mauro; Hu, Liangbing; La Mantia, Fabio; Cui, Yi

2012-01-01

In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

KAUST Repository

Pasta, Mauro

2012-06-01

In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

Order/disorder in electrodeposited aluminum-titanium alloys

Directory of Open Access Journals (Sweden)

Stafford G.R.

2003-01-01

Full Text Available The composition, morphology, and crystallographic microstructure of Al-Ti alloys electrodeposited from two different chloroaluminate molten salt electrolytes were examined. Alloys containing up to 28 % atomic fraction Ti were electrodeposited at 150 °C from 2:1 AlCl3-NaCl with controlled additions of Ti2+. The apparent limit on alloy composition is proposed to be due to a mechanism by which Al3Ti forms through the reductive decomposition of [Ti(AlCl43]-. The composition of Al-Ti alloys electrodeposited from the AlCl3-EtMeImCl melt at 80 °C is limited by the diffusion of Ti2+ to the electrode surface. Alloys containing up to 18.4 % atomic fraction Ti are only obtainable at high Ti2+ concentrations in the melt and low current densities. Alloys electrodeposited from the higher temperature melt have an ordered L12 crystal structure while alloys of similar composition but deposited at lower temperature are disordered fcc. The appearance of antiphase boundaries in the ordered alloys suggests that the deposit may be disordered initially and then orders in the solid state, subsequent to the charge transfer step and adatom incorporation into the lattice. This is very similar to the disorder-trapping observed in rapidly solidified alloys. The measured domain size is consistent with a mechanism of diffusion-controlled doman growth at the examined deposition temperatures and times.

Electrodeposition of CoNiMo thin films using glycine as additive: anomalous and induced codeposition

International Nuclear Information System (INIS)

Esteves, Marcos C.; Sumodjo, Paulo T.A.; Podlaha, Elizabeth J.

2011-01-01

Highlights: → Mixed/induced codeposition of CoNiMo from a glycine containing bath. → Deposition in a rotating cylinder Hull cell. → The mechanism is explained in term of the complex species that can be formed. - Abstract: The present study focuses on the behavior of the CoNiMo mixed anomalous/induced codeposition process, using glycine as a probe to influence the coverage of adsorbed intermediates. In order to facilitate the investigation of a wide variation of parameters the electrodeposition of the alloy films was performed using a rotating cylinder Hull cell. Alloy composition, current efficiency and partial currents of each metal were analyzed. The partial current densities and hence alloy composition was affected by the amount of glycine in the electrolyte: increasing glycine enhanced both cobalt and molybdenum deposition rates and hindered nickel deposition. It is suggested that the glycine facilitates the adsorption of M(I) adsorbed intermediates that control the anomalous and induced codeposition behavior. The current efficiency ranged from 30 up to 75% and was only slightly affected by glycine at high applied current densities. Films with a tridimensional porous structure were obtained applying current densities higher than 200 mA cm -2 , formed as a consequence of the large hydrogen evolution side reaction, presenting conditions for a novel Mo-alloy electrode structure.

Quantitative texture analysis of electrodeposited line patterns

DEFF Research Database (Denmark)

Pantleon, Karen; Somers, Marcel A.J.

2005-01-01

Free-standing line patterns of Cu and Ni were manufactured by electrochemical deposition into lithographically prepared patterns. Electrodeposition was carried out on top of a highly oriented Au-layer physically vapor deposited on glass. Quantitative texture analysis carried out by means of x......-ray diffraction for both the substrate layer and the electrodeposits yielded experimental evidence for epitaxy between Cu and Au. An orientation relation between film and substrate was discussed with respect to various concepts of epitaxy. While the conventional mode of epitaxy fails for the Cu...

Synthesizing the Nanocrytalline Cobalt-Iron Coating Through The Electrodeposition Process With Different Time Deposition

Science.gov (United States)

Rozlin Nik Masdek, Nik; Sorfian Hafiz Mansor, Mohd; Salleh, Zuraidah; Hyie, Koay Mei

2018-03-01

In the engineering world, electrodeposition or electroplating has become the most popular method of surface coating in improving corrosion behavior and mechanical properties of material. Therefore in this study, CoFe nanoparticle protective coating has been synthesized on the mild steel washer using electrodeposition method. The electrodeposition was conducted in the acidic environment with the pH value range from 1 to 2 with the controlled temperature of 50°C. The influence of deposition time (30, 60, 90 minutes) towards characteristic and properties such as particle size, surface morphology, corrosion behavior, and microhardness were studied in this investigation. Several results can be obtained by doing this experiment and testing. First, the surface morphology of Cobalt Iron (CoFe) on the electrodeposited mild steel washer are obtained. In addition, the microhardness of the mild steel washer due to the different deposition time are determined. Next, the observation on the difference in the grain size of CoFe that has been electrodeposited on the mild steel plate is made. Last but not least, the corrosion behavior was investigated. CoFe nanoparticles deposited for 30 minutes produced the smallest particle size and the highest microhardness of 86.17 and 236.84 HV respectively. The CoFe nanoparticles also exhibit the slowest corrosion rate at 30 minutes as compared to others. The crystalline size also increases when the time deposition is increased. The sample with 30 minute depositon time indicate the smallest crystalline size which is 15nm. The decrement of deposition time plays an important role in synthesizing CoFe nanoparticles with good corrosion resistance and microhardness. CoFe nanoparticles obtained at 30 minutes shows high corrosion resistance compared to others. In a nutshell, it was observed that the decrement of deposition time improved mechanical and corrosion properties of CoFe nanoparticles.

Nickel Nanowire@Porous NiCo2O4 Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

Directory of Open Access Journals (Sweden)

Houzhao Wan

2017-12-01

Full Text Available A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo2O4 nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo2O4 nanorods and construct the well-defined NiCo2O4 nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo2O4/Ni foam electrode shows a high areal specific capacitance (7.4 F cm−2 at 5 mA cm−2, excellent rate capability (88.04% retained at 100 mA cm−2, and good cycling stability (74.08% retained after 1,500 cycles. The superior electrochemical properties made it promising as electrode for supercapacitors.

A Preliminary Study on the Synthesis and Characterization of Multilayered Ag/Co Magnetic Nanowires Fabricated via the Electrodeposition Method

Directory of Open Access Journals (Sweden)

Cheng-Hsiung Peng

2013-01-01

Full Text Available A single-bath electrodeposition method was developed to integrate multilayer Ag/Co nanowires with a commercial anodic alumina oxide (AAO template with a pore diameter of 100–200 nm. An electrolyte system containing silver nitride and cobalt sulfide was studied using cyclic voltammetry, and the electrodeposition rate was varied to optimize the electrodeposition conditions. A constant stepwise potential and a variable cation ratio of [Co2+]/[Ag+] were used during electrodeposition. After the dissolution of the template in aqueous NaOH solution, multilayered Ag/Co nanowires were obtained with a composition of [Co]/[Ag80Co20], as identified by XRD and TEM, when [Co2+]/[Ag+] = 150. By annealing at 200°C for 1 h, uniformly structured (Co99.57/Ag100 nanowires were obtained. Compared with pure Co nanowires, the magnetic hysteresis loops showed a greater magnetic anisotropy for (Co99.57/Ag100 nanowires than for pure Co nanowires, corresponding to a change in the easy axis upon magnetization.

A Study on Zinc-Iron Alloy Electrodeposition from a Chloride Electrolyte

DEFF Research Database (Denmark)

Jensen, Jens Dahl

1998-01-01

The electrodeposition of zinc-iron alloys from a chloride-based electrolyte has been studied using electrochemical polarisation techniques, Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDXA) and Computer Assisted Pulse Plating (CAPP...... this system ideal for production of compositional modulated alloy (CMA) electrodeposits. Chloride content, pH and agitation of the electrolyte have been observed to have a strong influence on the reaction at the cathode surface, just as the use of pulse reversal current during electrodeposition. A theory...

Phase-Change Memory Properties of Electrodeposited Ge-Sb-Te Thin Film

Science.gov (United States)

Huang, Ruomeng; Kissling, Gabriela P.; Jolleys, Andrew; Bartlett, Philip N.; Hector, Andrew L.; Levason, William; Reid, Gillian; De Groot, C. H. `Kees'

2015-11-01

We report the properties of a series of electrodeposited Ge-Sb-Te alloys with various compositions. It is shown that the Sb/Ge ratio can be varied in a controlled way by changing the electrodeposition potential. This method opens up the prospect of depositing Ge-Sb-Te super-lattice structures by electrodeposition. Material and electrical characteristics of various compositions have been investigated in detail, showing up to three orders of magnitude resistance ratio between the amorphous and crystalline states and endurance up to 1000 cycles.

Preparation of cuxinygazsen (X=0-2, Y=0-2, Z=0-2, N=0-3) precursor films by electrodeposition for fabricating high efficiency solar cells

Science.gov (United States)

Bhattacharya, Raghu N.; Contreras, Miguel A.; Keane, James; Tennant, Andrew L.; Tuttle, John R.; Ramanathan, Kannan; Noufi, Rommel

1998-03-24

High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

Stable lithium electrodeposition in salt-reinforced electrolytes

KAUST Repository

Lu, Yingying

2015-04-01

© 2015 Elsevier B.V. Development of high-energy lithium-based batteries that are safe remains a challenge due to the non-uniform lithium electrodeposition during repeated charge and discharge cycles. We report on the effectiveness of lithium bromide (LiBr) salt additives in a common liquid electrolyte (i.e. propylene carbonate (PC)) on the stability of lithium electrodeposition. From galvanostatic cycling measurements, we find that the presence of LiBr in PC provides more than 20-fold enhancement in cell lifetime over the control LiTFSI/PC electrolyte. Batteries containing 30 mol% LiBr additive in the electrolytes are able to cycle stably for at least 1.8 months with no observations of cell failure. From galvanostatic polarization measurements, an electrolyte containing 30 mol% LiBr shows a maximum improvement in lifetime. The formation of uneven lithium electrodeposits is significantly suppressed by the Br-containing SEI layers, evidenced by impedance spectra, post-mortem SEM and XPS analyses. The study also concludes that good solubility of halogenated salts is not necessary for achieving the observed improvements in cell lifetime.

Electrodeposition, characterization and corrosion behaviour of tin-20 wt.% zinc coatings electroplated from a non-cyanide alkaline bath

International Nuclear Information System (INIS)

Dubent, S.; Mertens, M.L.A.D.; Saurat, M.

2010-01-01

Tin-zinc alloy electroplated coatings are recognized as a potential alternative to toxic cadmium as corrosion resistant deposits because they combine the barrier protection of tin with the cathodic protection afforded by zinc. The coatings containing 20 wt.% zinc, balance tin, offer excellent corrosion protection for steel and do not form gross voluminous white corrosion products like pure zinc or high zinc alloy deposits. In this study, the effects of variables of the process (i.e. cathodic current density, pH and temperature) on deposit composition have been evaluated using a Hull cell to obtain 20 wt.% zinc alloy coatings. The tin-20 wt.% zinc deposits, produced with electroplating optimized conditions, were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray fluorescence spectrometry (XRF) and glow discharge optical emission spectrometry (GDOES). On the other hand, the corrosion behaviour of tin-zinc alloy electroplated coatings on steel has been investigated using electrochemical methods in a 3 wt.% NaCl solution and the salt spray test. The performance of the deposits was compared with cadmium and zinc-nickel electrodeposited coatings. The results show that the corrosion resistance of tin-20 wt.% zinc alloy coating is superior to that of cadmium and zinc-12 wt.% nickel coatings. Finally, sliding friction tests were conducted.

Electrodeposition of gallium and zinc onto aluminium. Influence of the electrodeposited metals on the activation process

International Nuclear Information System (INIS)

Flamini, D.O.; Saidman, S.B.; Bessone, J.B.

2007-01-01

The electrodeposition of gallium and/or zinc on aluminium, aluminium-zinc alloy and vitreous carbon electrodes in chloride solutions is analysed. The electrodissolution of the formed interfaces is also described and discussed. For this purpose, potentiodynamic and potentiostatic techniques and open circuit potential measurements were employed and surface characterisation was performed by scanning electron microscopy and energy dispersive X-ray analysis. The presence of zinc, electrodeposited from the solution or as an alloying component, facilitates gallium enrichment at the interface and improves the wetting on the aluminium oxide. These conditions ensure the formation of a surface Ga-Al amalgam. As a result, the dissolution process occurs at potentials which are more active than those observed for aluminium or aluminium-zinc alloy in halide solutions

Electrodeposition of gallium and zinc onto aluminium. Influence of the electrodeposited metals on the activation process

Energy Technology Data Exchange (ETDEWEB)

Flamini, D.O. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Saidman, S.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)], E-mail: ssaidman@criba.edu.ar; Bessone, J.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

2007-07-31

The electrodeposition of gallium and/or zinc on aluminium, aluminium-zinc alloy and vitreous carbon electrodes in chloride solutions is analysed. The electrodissolution of the formed interfaces is also described and discussed. For this purpose, potentiodynamic and potentiostatic techniques and open circuit potential measurements were employed and surface characterisation was performed by scanning electron microscopy and energy dispersive X-ray analysis. The presence of zinc, electrodeposited from the solution or as an alloying component, facilitates gallium enrichment at the interface and improves the wetting on the aluminium oxide. These conditions ensure the formation of a surface Ga-Al amalgam. As a result, the dissolution process occurs at potentials which are more active than those observed for aluminium or aluminium-zinc alloy in halide solutions.

Electrodeposition route to synthesize cigs films – an economical way ...

African Journals Online (AJOL)

Electrodeposition route to synthesize cigs films – an economical way to harness solar energy. ... for solar cells, how the charge separation in this nano scale photovoltaic (PV) materials occurs which help in absorption of radiation, and the electro-deposition route, a low cost one, produces thin film solar cells are analyzed.

DC electrodeposition of NiGa alloy nanowires in AAO template

Energy Technology Data Exchange (ETDEWEB)

Maleki, K. [Nanomaterials Group, Department of Materials Engineering, Tarbiat Modares University, Iran, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Sanjabi, S., E-mail: sanjabi@modares.ac.ir [Nanomaterials Group, Department of Materials Engineering, Tarbiat Modares University, Iran, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Alemipour, Z. [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2015-12-01

NiGa alloy nanowires were electrodeposited from an acidic sulfate bath into nanoporous anodized alumina oxide (AAO). This template was fabricated by two-step anodizing. The effects of bath composition and current density were explored on the Ga content of electrodeposited nanowires. The Ga content in the deposits was increased by increasing both Ga in the bath composition and electrodepositing current density. The NiGa alloy nanowires were synthesized for Ga content up to 2–4% without significant improving the magnetic properties. Above this threshold Ga clusters were formed and decreased the magnetic properties of the nanowires. For Ga content of the alloy above 30%, the wires were too short and incomplete. X-ray diffraction patterns reveal that the significant increase of Ga content in the nanowires, changes the FCC crystal structure of Ni to an amorphous phase. It also causes a sizeable increase in the Ga cluster size; these both lead to a significant reduction in the coercivity and the magnetization respectively. - Highlights: • NiGa alloy nanowires were electrodeposited from acidic sulphate baths into nanoporous anodized alumina oxide (AAO) template. • The Ga content was increased by increasing the Ga in the bath composition and electrodeposition current density. • The magnetic parameters such as coercivity and magnetization were not changed for the alloy nanowire with Ga content less than 4%.

Absorption and retention of nickel from drinking water in relation to food intake and nickel sensitivity.

Science.gov (United States)

Nielsen, G D; Søderberg, U; Jørgensen, P J; Templeton, D M; Rasmussen, S N; Andersen, K E; Grandjean, P

1999-01-01

Two studies were performed to examine the influence of fasting and food intake on the absorption and retention of nickel added to drinking water and to determine if nickel sensitization played any role in this regard. First, eight nonallergic male volunteers fasted overnight before being given nickel in drinking water (12 micrograms Ni/kg) and, at different time intervals, standardized 1400-kJ portions of scrambled eggs. When nickel was ingested in water 30 min or 1 h prior to the meal, peak nickel concentrations in serum occurred 1 h after the water intake, and the peak was 13-fold higher than the one seen 1 h after simultaneous intake of nickel-containing water and scrambled eggs. In the latter case, a smaller, delayed peak occurred 3 h after the meal. Median urinary nickel excretion half-times varied between 19.9 and 26.7 h. Within 3 days, the amount of nickel excreted corresponded to 2.5% of the nickel ingested when it was mixed into the scrambled eggs. Increasing amounts were excreted as the interval between the water and the meal increased, with 25.8% of the administered dose being excreted when the eggs were served 4 h prior to the nickel-containing drinking water. In the second experiment, a stable nickel isotope, 61Ni, was given in drinking water to 20 nickel-sensitized women and 20 age-matched controls, both groups having vesicular hand eczema of the pompholyx type. Nine of 20 nickel allergic eczema patients experienced aggravation of hand eczema after nickel administration, and three also developed a maculopapular exanthema. No exacerbation was seen in the control group. The course of nickel absorption and excretion in the allergic groups did not differ and was similar to the pattern seen in the first study, although the absorption in the women was less. A sex-related difference in gastric emptying rates may play a role. Thus, food intake and gastric emptying are of substantial significance for the bioavailability of nickel from aqueous solutions

Investigation of mechanical properties and operative deformation mechanism in nano-crystalline Ni–Co/SiC electrodeposits

International Nuclear Information System (INIS)

Lari Baghal, S.M.; Amadeh, A.; Heydarzadeh Sohi, M.

2012-01-01

Highlights: ► The tensile properties of Ni–Co and Ni–Co/SiC deposits were investigated. ► The SiC particles enhanced tensile strength and ductility of nano-structured composites. ► The deformation mechanism at low and high strain rates were studied. - Abstract: Ni–Co/SiC nano-composites were prepared via electrodeposition from a modified Watts bath containing SiC particles with average particle size of 50 nm, SDS as surfactant and saccharin as grain refiner in appropriate amounts. The effect of nano-particle incorporation on microstructure, mechanical properties and deformation mechanism of electrodeposits were investigated. The mechanical properties of electrodeposits were investigated by Vickers microhardness and tensile tests. The results indicated that incorporation of SiC particles into a 15 nm Ni–Co matrix had no considerable effect on its microhardness and yield strength, that is, dispersion hardening did not operate in this range of grain size. However it was observed that co-deposition of uniform distributed SiC particles can significantly improve the ultimate tensile strength and elongation to failure of the deposits. Calculation of apparent activation volume from tensile test results at different strain rates proved that incorporation of SiC nano-particles are responsible for stress-assisted activation of GB atoms mechanism that can significantly increase the plasticity. Nano-crystalline Ni–Co matrix showed a mixed mod behavior of ductile and brittle fracture whereas incorporation of SiC particles and increasing the strain rate promoted ductile fracture mode.

Performance improvement of pasted nickel electrodes with multi-wall carbon nanotubes for rechargeable nickel batteries

International Nuclear Information System (INIS)

Song, Q.S.; Aravindaraj, G.K.; Sultana, H.; Chan, S.L.I.

2007-01-01

Carbon nanotubes (CNTs) were employed as a functional additive to improve the electrochemical performance of pasted nickel-foam electrodes for rechargeable nickel-based batteries. The nickel electrodes were prepared with spherical β-Ni(OH) 2 powder as the active material and various amounts of CNTs as additives. Galvanostatic charge/discharge cycling tests showed that in comparison with the electrode without CNTs, the pasted nickel electrode with added CNTs exhibited better electrochemical properties in the chargeability, specific discharge capacity, active material utilization, discharge voltage, high-rate capability and cycling stability. Meanwhile, the CNT addition also lowered the packing density of Ni(OH) 2 particles in the three-dimensional porous nickel-foam substrate, which could lead to the decrease in the active material loading and discharge capacity of the electrode. Hence, the amount of CNTs added to Ni(OH) 2 should be optimized to obtain a high-performance nickel electrode, and an optimum amount of CNT addition was found to be 3 wt.%. The superior electrochemical performance of the nickel electrode with CNTs could be attributed to lower electrochemical impedance and less γ-NiOOH formed during charge/discharge cycling, as indicated by electrochemical impedance spectroscopy and X-ray diffraction analyses. Thus, it was an effective method to improve the electrochemical properties of pasted nickel electrodes by adding an appropriate amount of CNTs to spherical Ni(OH) 2 as the active material

Electrodeposition of Zn and Cu–Zn alloy from ZnO/CuO precursors in deep eutectic solvent

Energy Technology Data Exchange (ETDEWEB)

Xie, Xueliang [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zou, Xingli, E-mail: xinglizou@shu.edu.cn [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Lu, Xionggang, E-mail: luxg@shu.edu.cn [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Lu, Changyuan; Cheng, Hongwei; Xu, Qian [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhou, Zhongfu [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth SY23 3BZ (United Kingdom)

2016-11-01

Graphical abstract: Micro/nanostructured Zn and Cu–Zn alloy films have been electrodeposited directly from ZnO/CuO precursors in ChCl/urea-based DES, the typical nucleation-growth mechanism and the micro/nanostructures-formation process are determined. Display Omitted - Highlights: • Micro/nanostructured Zn films have been electrodeposited directly from ZnO precursor in deep eutectic solvent (DES). • The morphology of the Zn electrodeposits depends on the cathodic potential and temperature. • The electrodeposited Zn films exhibit homogeneous morphologies with controllable particle sizes and improved corrosion resistance. • Cu–Zn alloy films have also been electrodeposited directly from their metal oxides precursors in DES. - Abstract: The electrodeposition of Zn and Cu–Zn alloy has been investigated in choline chloride (ChCl)/urea (1:2 molar ratio) based deep eutectic solvent (DES). Cyclic voltammetry study demonstrates that the reduction of Zn(II) to Zn is a diffusion-controlled quasi-reversible, one-step, two electrons transfer process. Chronoamperometric investigation indicates that the electrodeposition of Zn on a Cu electrode typically involves three-dimensional instantaneous nucleation with diffusion-controlled growth process. Micro/nanostructured Zn films can be obtained by controlling the electrodeposition potential and temperature. The electrodeposited Zn crystals preferentially orient parallel to the (101) plane. The Zn films electrodeposited under more positive potentials and low temperatures exhibit improved corrosion resistance in 3 wt% NaCl solution. In addition, Cu–Zn alloy films have also been electrodeposited directly from CuO–ZnO precursors in ChCl/urea-based DES. The XRD analysis indicates that the phase composition of the electrodeposited Cu–Zn alloy depends on the electrodeposition potential.

Electrochemical deposition of Ni coating on Cu substrate in ethylene glycol + iCl/sub 2/.6H/sub 2/0 electrolyte characterization of Ni coatings

International Nuclear Information System (INIS)

Ghaffar, A.

2011-01-01

The primary objective of this work was to develop the technical know-how regarding the electrodeposition technique and the parameters affecting the quality of the electrodeposit such as electrolyte nature, its pH, current density, potential, substrate material etc. The ethylene glycol based organic electrolyte was employed to improve the aesthetics, surface and structural properties of nickel electroplatings. For the purpose of achieving improvements in nickel plating, a comparative work-study was carried out using aqueous and organic electrolytes. The voltammetric experiments were performed to find out the electroactive potential domain of ethylene glycol electrolyte, or in other words, to get the current density and potential ranges suitable for electrodeposition of nickel on copper substrate. Electroplating was carried out galvanostatically at different current densities and concentrations to find out the quality of Ni electrodeposit in both aqueous and organic electrolytes. The most suited electrolyte concentration (0.6 M hydrated nickel chloride dissolved in corresponding electrolytic solvent) and current density (1 mA/cm/sup 2/) were chosen to carry out nickel plating in aqueous electrolyte as well as in ethylene glycol electrolyte. Subsequently, current efficiencies were calculated for both electrolytes to find out the improvement in the quality of Ni deposit. Finally, the material characterization techniques such as X-ray diffraction, scanning electron microscopy, atomic force microscopy and adhesion testing were performed to fully access the composition, structure and surface morphology of nickel coating. (author)

Microstructure stability of silver electrodeposits at room temperature

International Nuclear Information System (INIS)

Hansen, Karsten; Pantleon, Karen

2008-01-01

In situ quantitative X-ray diffraction analysis was used to investigate the kinetics of microstructure evolution at room temperature (self-annealing) in an electrodeposited silver layer. As a function of time at room temperature the as-deposited nanocrystalline microstructure evolved considerably: orientation-dependent grain growth and changes of the preferred grain orientation occurred. It is demonstrated for the first time that self-annealing occurs for electrodeposited silver layers and, hence, is not a unique feature of copper as often suggested

Interfacial electronic structure of electrodeposited Ag nanoparticles on iron oxide nanorice particles

Energy Technology Data Exchange (ETDEWEB)

Sohn, Young Ku [Dept. of Chemistry, Yeungnam University, Gyeongsan (Korea, Republic of)

2016-12-15

A bimetallic hybrid nanostructure of uni- formly electrodeposited Ag NPs on an Fe oxide nanorice particle template was developed. Figure 6 schematically illustrates uniform electrodeposition of Ag NPs on Fe oxide nanorice supported on a Si substrate. According to Ar + ion depth-probling XPS spectra, the electrodeposited Ag NPs are metallic, and the Fe oxide nanorice particles consist of a metallic shell covered by ultrathin FeOOH or Fe 2 O 3 shells. When the template was functionalized with 1,4-diisocyanobenzene, one terminal NC group was bridge- bonded as in the N C form on the Fe surface. The newly developed selective facial electrodeposition method will be very useful for facial fabrication of bimetallic hybrid systems for diverse application areas.

Influence of titanium oxide films on copper nucleation during electrodeposition

International Nuclear Information System (INIS)

Chang, Hyun K.; Choe, Byung-Hak; Lee, Jong K.

2005-01-01

Copper electrodeposition has an important industrial role because of various interconnects used in electronic devices such as printed wire boards. With an increasing trend in device miniaturization, in demand are void-free, thin copper foils of 10 μm thick or less with a very low surface profile. In accordance, nucleation kinetics of copper was studied with titanium cathodes that were covered with thin, passive oxide films of 2-3 nm. Such an insulating oxide layer with a band gap of 3 eV is supposed to nearly block charge transfer from the cathode to the electrolyte. However, significant nucleation rates of copper were observed. Pipe tunneling mechanism along a dislocation core is reasoned to account for the high nucleation kinetics. A dislocation core is proposed to be a high electron tunneling path with a reduced energy barrier and a reduced barrier thickness. In supporting the pipe tunneling mechanism, both 'in situ' and 'ex situ' scratch tests were performed to introduce extra dislocations into the cathode surface, that is, more high charge paths via tunneling, before electrodeposition

Electrodeposited nanostructured raspberry-like gold-modified electrodes for electrocatalytic applications

Energy Technology Data Exchange (ETDEWEB)

Manivannan, Shanmugam; Ramaraj, Ramasamy, E-mail: ramarajr@yahoo.com [Madurai Kamaraj University, Centre for Photoelectrochemistry, School of Chemistry (India)

2013-10-15

A facile method for fabrication of raspberry-like Au nanostructures (Au NRBs)-modified electrode by electrodeposition and its applications toward the electrocatalytic oxidation of methanol (MOR) in alkaline medium and oxygen reduction reaction (ORR) in both alkaline and acidic media are demonstrated. The Au NRBs are characterized by UV-Vis absorption spectra, SEM, X-ray diffraction, and electrochemical measurements. The growth of Au NRBs was monitored by recording the in-situ absorption spectral changes during electrodeposition using spectroelectrochemical technique. Here we systematically studied the MOR by varying several reaction parameters such as potential scan rate and methanol concentration. The electrocatalytic poisoning effect due to the MOR products are not observed at the Au NRBs-modified electrode. At the alkaline medium the Au NRBs-modified electrode shows the better catalytic activities toward the MOR and ORR when compared to the poly crystalline gold and bare glassy carbon electrodes. The Au NRBs-modified electrode is a promising and inexpensive electrode material for other electrocatalytic applications.Graphical AbstractRaspberry-like Au nanostructures modified electrode is prepared and used for electrocatalytic applications.

Use of carriers for to electrodeposited radium 226

International Nuclear Information System (INIS)

Iturbe, J.L.

1991-10-01

The form of the energy distribution of a monoenergetic alpha particle starting from some emitting source of these particles, it depends on the quantity of material that its cross before being detected. Some authors deposit to the radium-226 by means of direct evaporation of the solution on metallic supports, on millipore paper and by electrodeposition. Some other ones place the radium solution in scintillation liquid, to quantify it by this technique. The objective of the present work is using carriers with the same oxidation state of the radium, that is to say of 2 + , for treating to be electrodeposited to the radium-226 with the biggest possible percentage for later use the alpha spectroscopy technique to quantify it. The carriers that have been used until its they are barium and zinc in form of barium chloride, zinc nitrate and zinc sulfate. The first results indicate that with the zinc solution a yield of 40% of electrodeposited radium has been reached. (Author)

Effect of surfactant on electrodeposited Ni-P layer as an under bump metallization

International Nuclear Information System (INIS)

Lin, Yung-Chi; Duh, Jenq-Gong

2007-01-01

In the microelectronic industry, the nickel plating has been used as the under bump metallization (UBM). The electroplated process was demonstrated to be a favorable alternative approach to produce the Ni-P layer as UBM. In this study, the role of sodium dodecylsulfate (SDS) addition in electrodeposition was investigated. The variations on surface morphology and surface roughness in the SDS-added process of electroplated Ni-P were revealed with both field emission scanning electronic microscope and atomic force microscope. The influence of SDS addition process in wettability of several commercial solder pastes, including Sn-37Pb, Sn-3.5Ag, and Sn-3.0Ag-0.5Cu, on electroplated Ni-P with various phosphorous contents was evaluated. The surface morphology and the surface roughness of Ni-P layer were affected by SDS addition. It was demonstrated that modified surface morphology and surface roughness acted to enhance the wettability of electroplated Ni-P. In addition, the interfacial reactions between Sn-3.0Ag-0.5Cu and electroplated Ni-P UBM with SDS addition during deposition was also probed and discussed

Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes

OpenAIRE

Maijenburg, A.W.

2014-01-01

This thesis is entitled “Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes”. Templated electrodeposition is the synthesis technique that was used throughout this thesis, and it comprises the use of a template with specific shape and dimensions for the formation of different types of nanostructures. Throughout this thesis, three different nanostructures were made: nanowires (Chapters 2 to 6), nanotubes (Chapters 2 and 5) and nanocubes (Chapters 7 and ...

Nucleation and growth in alkaline zinc electrodeposition An Experimental and Theoretical study

Science.gov (United States)

Desai, Divyaraj

The current work seeks to investigate the nucleation and growth of zinc electrodeposition in alkaline electrolyte, which is of commercial interest to alkaline zinc batteries for energy storage. The morphology of zinc growth places a severe limitation on the typical cycle life of such batteries. The formation of mossy zinc leads to a progressive deterioration of battery performance while zinc dendrites are responsible for sudden catastrophic battery failure. The problems are identified as the nucleation-controlled formation of mossy zinc and the transport-limited formation of dendritic zinc. Consequently, this thesis work seeks to investigate and accurately simulate the conditions under which such morphologies are formed. The nucleation and early-stage growth of Zn electrodeposits is studied on carbon-coated TEM grids. At low overpotentials, the morphology develops by aggregation at two distinct length scales: ~5 nm diameter monocrystalline nanoclusters form ~50nm diameter polycrystalline aggregates, and second, the aggregates form a branched network. Epitaxial (0002) growth above a critical overpotential leads to the formation of hexagonal single-crystals. A kinetic model is provided using the rate equations of vapor solidification to simulate the evolution of the different morphologies. On solving these equations, we show that aggregation is attributed to cluster impingement and cluster diffusion while single-crystal formation is attributed to direct attachment. The formation of dendritic zinc is investigated using in-operando transmission X-ray microscopy which is a unique technique for imaging metal electrodeposits. The nucleation density of zinc nuclei is lowered using polyaniline films to cover the active nucleation sites. The effect of overpotential is investigated and the morphology shows beautiful in-operando formation of symmetric zinc crystals. A linear perturbation model was developed to predict the growth and formation of these crystals to first

Kinetics of oxidation of nickel(II) aza macrocycles by ...

Indian Academy of Sciences (India)

The kinetics of the oxidation of nickel (II) hexaaza and nickel (II) pentaaza macrocycles by the peroxydisulphate anion, S2O8 2-, were studied in aqueous media. Effect of H on reaction rate was also studied. The rate increases with increase of S2OO8 2- concentration. Rates are almost independent of acid between H 4 ...

Structural characterization of electrodeposited boron

Indian Academy of Sciences (India)

Structural characterization of electrodeposited boron was carried out by using transmission electron microscopy and Raman spectroscopy. Electron diffraction and phase contrast imaging were carried out by using transmission electron microscopy. Phase identification was done based on the analysis of electron diffraction ...

Utilization of electrodeposition for electrothermal atomic absorption spectrometry determination of gold

International Nuclear Information System (INIS)

Konecna, Marie; Komarek, Josef

2007-01-01

Gold was determined by electrothermal atomic absorption spectrometry after electrochemical preconcentration on the graphite ridge probe used as a working electrode and sample support. The probe surface was electrochemically modified with Pd, Re and the mixture of both. The electrolysis of gold was performed under galvanostatic control at 0.5 mA. Maximum pyrolysis temperature for the probe surface modified with Pd was 1200 deg. C, with Re 1300 deg. C. The relative standard deviation for the determination of 2 μg l -1 Au was not higher than 5.6% (n = 8) for 2 min electrodeposition. The sensitivity of gold determination was reproducible for 300 electrodeposition and atomization cycles. When the probe surface was modified with a mixture of Pd and Re the detection limit was 31 ng l -1 for 2 min electrodeposition, 3.7 ng l -1 for 30 min, 1.5 ng l -1 for 1 h and 0.4 ng l -1 for 4 h electrodeposition, respectively. The procedure was applied to the determination of gold in river water samples. The relative standard deviation for the determination of 2.5 ng l -1 Au at 4 h electrodeposition time at 0.5 mA was 7.5%

Insights into the superhydrophobicity of metallic surfaces prepared by electrodeposition involving spontaneous adsorption of airborne hydrocarbons

International Nuclear Information System (INIS)

Liu, Peng; Cao, Ling; Zhao, Wei; Xia, Yue; Huang, Wei; Li, Zelin

2015-01-01

Graphical abstract: - Highlights: • Several superhydrophobic metallic surfaces were fabricated by fast electrodeposition. • Both micro/nanostructures and adsorption of airborne hydrocarbons make contributions. • XPS analyses confirm presence of airborne hydrocarbons on these metallic surfaces. • The adsorption of airborne hydrocarbons on the clean metal Au surface was very quick. • UV-O 3 treatment oxidized the hydrocarbons to hydrophilic oxygen-containing organics. - Abstract: Electrochemical fabrication of micro/nanostructured metallic surfaces with superhydrophobicity has recently aroused great attention. However, the origin still remains unclear why smooth hydrophilic metal surfaces become superhydrophobic by making micro/nanostructures without additional surface modifications. In this work, several superhydrophobic micro/nanostructured metal surfaces were prepared by a facile one-step electrodeposition process, including non-noble and noble metals such as copper, nickel, cadmium, zinc, gold, and palladium with (e.g. Cu) or without (e.g. Au) surface oxide films. We demonstrated by SEM and XPS that both hierarchical micro/nanostructures and spontaneous adsorption of airborne hydrocarbons endowed these surfaces with excellent superhydrophobicity. We revealed by XPS that the adsorption of airborne hydrocarbons at the Ar + -etched clean Au surface was rather quick, such that organic contamination can hardly be prevented in practical operation of surface wetting investigation. We also confirmed by XPS that ultraviolet-O 3 treatment of the superhydrophobic metal surfaces did not remove the adsorbed hydrocarbons completely, but mainly oxidized them into hydrophilic oxygen-containing organic substances. We hope our findings here shed new light on deeper understanding of superhydrophobicity for micro/nanostructured metal surfaces with and without surface oxide films

Improved electrochemical performances of CuO nanotube array prepared via electrodeposition as anode for lithium ion battery

Energy Technology Data Exchange (ETDEWEB)

Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

2015-10-15

Graphical abstract: CuO nanotube array electrodes prepared by electrodeposition method exhibit an excellent lithium ion storage ability as anode of Li-ion battery. - Highlights: • CuO nanotube arrays are synthesized by an electrodeposition method. • CuO nanotube shows a high-rate performance. • CuO nanotube shows an excellent cycling performance. - Abstract: We report a facile strategy to prepared CuO nanotube arrays directly grown on Cu plate through the electrodeposition method. The as-prepared CuO nanotubes show a quasi-cylinder nanostructure with internal diameters of ca. ∼100 nm, external diameters of ca. ∼120 nm, and average length of ∼3 μm. As an anode for lithium ion batteries, the electrochemical properties of the CuO nanotube arrays are investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests. Due to the unique nanotube nanostructure, the as-prepared CuO electrodes exhibit good rate performance (550 mAh g{sup −1} at 0.1 C and 464 mAh g{sup −1} at 1 C) and cycling performance (581 mAh g{sup −1} at 0.1 C and 538 mAh g{sup −1} at 0.5 C)

Controllable Growth of Ga Film Electrodeposited from Aqueous Solution and Cu(In,Ga)Se2 Solar Cells.

Science.gov (United States)

Bi, Jinlian; Ao, Jianping; Gao, Qing; Zhang, Zhaojing; Sun, Guozhong; He, Qing; Zhou, Zhiqiang; Sun, Yun; Zhang, Yi

2017-06-07

Electrodepositon of Ga film is very challenging due to the high standard reduction potential (-0.53 V vs SHE for Ga 3+ ). In this study, Ga film with compact structure was successfully deposited on the Mo/Cu/In substrate by the pulse current electrodeposition (PCE) method using GaCl 3 aqueous solution. A high deposition rate of Ga 3+ and H + can be achieved by applying a large overpotential induced by high pulse current. In the meanwhile, the concentration polarization induced by cation depletion can be minimized by changing the pulse frequency and duty cycle. Uniform and smooth Ga film was fabricated at high deposition rate with pulse current density 125 mA/cm 2 , pulse frequency 5 Hz, and duty cycle 0.25. Ga film was then selenized together with electrodeposited Cu and In films to make a CIGSe absorber film for solar cells. The solar cell based on the Ga film presents conversion efficiency of 11.04%, fill factor of 63.40%, and V oc of 505 mV, which is much better than those based on the inhomogeneous and rough Ga film prepared by the DCE method, indicating the pulse current electrodeposition process is promising for the fabrication of CIGSe solar cell.

Hydrogen evolution reaction at Ru-modified nickel-coated carbon fibre in 0.1 M NaOH

Directory of Open Access Journals (Sweden)

Pierożyński Bogusław

2015-03-01

Full Text Available The electrochemical activity towards hydrogen evolution reaction (HER was studied on commercially available (Toho-Tenax and Ru-modified nickel-coated carbon fibre (NiCCF materials. Quality and extent of Ru electrodeposition on NiCCF tows were examined by means of scanning electron microscopy (SEM. Kinetics of the hydrogen evolution reaction were investigated at room temperature, as well as over the temperature range: 20-50°C in 0.1 M NaOH solution for the cathodic overpotential range: -100 to -300 mV vs. RHE. Corresponding values of charge-transfer resistance, exchange current-density for the HER and other electrochemical parameters for the examined fibre tow composites were recorded.

The fabrication of short metallic nanotubes by templated electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Chienwen, Huang; Hao Yaowu, E-mail: yhao@uta.ed [Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, TX 76051 (United States)

2009-11-04

Template-based electrochemical synthesis has widely been used to produce metal nanowires and nanorods. Commercially available filtration membranes, such as anodic aluminum oxide (AAO) and polycarbonate track etch membranes, have commonly been utilized as hard templates for this purpose. In this process, a thick metal film is usually sputtered or vacuum evaporated onto one side of the membrane to block the pores and serve as the working electrode for the subsequent electrodeposition. Here, we show that during the deposition of the metal electrode for AAO membranes, the electrode metal diffuses into the pores and is deposited on the pore walls which leads to preferential electrodeposition of metal on the walls and therefore forms metal tubes. This phenomenon has been utilized to fabricate short nanotubes by carefully controlling the electrodeposition conditions. The process is a straightforward method for any electroplatable materials to form nanoscale tubular structures. The effects of working electrodes and electrodeposition conditions on the formation of tubular structures are discussed in detail. A new mechanism based on this simple fact is proposed to explain the formation of Ni tubes by Ni-Cu co-deposition. Also, we demonstrate how to distinguish magnetic nanotubes from nanorods by a simple magnetic measurement.

The fabrication of short metallic nanotubes by templated electrodeposition

International Nuclear Information System (INIS)

Huang Chienwen; Hao Yaowu

2009-01-01

Template-based electrochemical synthesis has widely been used to produce metal nanowires and nanorods. Commercially available filtration membranes, such as anodic aluminum oxide (AAO) and polycarbonate track etch membranes, have commonly been utilized as hard templates for this purpose. In this process, a thick metal film is usually sputtered or vacuum evaporated onto one side of the membrane to block the pores and serve as the working electrode for the subsequent electrodeposition. Here, we show that during the deposition of the metal electrode for AAO membranes, the electrode metal diffuses into the pores and is deposited on the pore walls which leads to preferential electrodeposition of metal on the walls and therefore forms metal tubes. This phenomenon has been utilized to fabricate short nanotubes by carefully controlling the electrodeposition conditions. The process is a straightforward method for any electroplatable materials to form nanoscale tubular structures. The effects of working electrodes and electrodeposition conditions on the formation of tubular structures are discussed in detail. A new mechanism based on this simple fact is proposed to explain the formation of Ni tubes by Ni-Cu co-deposition. Also, we demonstrate how to distinguish magnetic nanotubes from nanorods by a simple magnetic measurement.

Metal-organic framework templated electrodeposition of functional gold nanostructures

International Nuclear Information System (INIS)

Worrall, Stephen D.; Bissett, Mark A.; Hill, Patrick I.; Rooney, Aidan P.; Haigh, Sarah J.; Attfield, Martin P.; Dryfe, Robert A.W.

2016-01-01

Highlights: • Electrodeposition of anisotropic Au nanostructures templated by HKUST-1. • Au nanostructures replicate ∼1.4 nm pore spaces of HKUST-1. • Encapsulated Au nanostructures active as SERS substrate for 4-fluorothiophenol. - Abstract: Utilizing a pair of quick, scalable electrochemical processes, the permanently porous MOF HKUST-1 was electrochemically grown on a copper electrode and this HKUST-1-coated electrode was used to template electrodeposition of a gold nanostructure within the pore network of the MOF. Transmission electron microscopy demonstrates that a proportion of the gold nanostructures exhibit structural features replicating the pore space of this ∼1.4 nm maximum pore diameter MOF, as well as regions that are larger in size. Scanning electron microscopy shows that the electrodeposited gold nanostructure, produced under certain conditions of synthesis and template removal, is sufficiently inter-grown and mechanically robust to retain the octahedral morphology of the HKUST-1 template crystals. The functionality of the gold nanostructure within the crystalline HKUST-1 was demonstrated through the surface enhanced Raman spectroscopic (SERS) detection of 4-fluorothiophenol at concentrations as low as 1 μM. The reported process is confirmed as a viable electrodeposition method for obtaining functional, accessible metal nanostructures encapsulated within MOF crystals.

Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

KAUST Repository

Lu, Yingying

2014-08-10

Rechargeable lithium, sodium and aluminium metal-based batteries are among the most versatile platforms for high-energy, cost-effective electrochemical energy storage. Non-uniform metal deposition and dendrite formation on the negative electrode during repeated cycles of charge and discharge are major hurdles to commercialization of energy-storage devices based on each of these chemistries. A long-held view is that unstable electrodeposition is a consequence of inherent characteristics of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid electrolytes reinforced with halogenated salt blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolyte/lithium interface and impedance analysis of the interface during different stages of cell operation. Our findings provide support for an important recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of lithium halide salts. Our results also show that a high electrolyte modulus is unnecessary for stable electrodeposition of lithium.

Alloy formation during chromium electrodeposition at niobium cathode in molten salts

International Nuclear Information System (INIS)

Kuznetsov, S.A.; Glagolevskaya, A.L.

1993-01-01

Alloy formation during electrodeposition of chromium at niobium cathode is studied in salt melts. It is shown that during chromium electrodeposition at niobium support intermetallic compound Cr 2 Nb is formed. Thermodynamic characteristics of Cr 0.66 Nb 0.33 alloy are determined. 10 refs., 1 fig

Potentiostatic electro-deposition of 241Am using room temperature ionic liquids

International Nuclear Information System (INIS)

Sankhe, R.H.; Mirashi, N.N.; Arijit Sengupta; Murali, M.S.

2015-01-01

An attempt was made for the potentiostatic electrodeposition of 241 Am using six different room temperature ionic liquids (RTILs). Effect of electrodeposition time on the % of electrodeposition of 241 Am, pH change of the solution and the temperature change of the systems were investigated. It was observed that for water immiscible RTILs, the least viscous RTIL gave the best yield (when mixed with iso-propanol), while for water miscible RTILs, reverse trend was observed (when mixed with water). Out of all water immiscible RTILs under consideration for the present case, the octyl-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (C 8 mpyNTf 2 ) in isopropanol was found to yield almost quantitative (99.6 %) electrodeposition of 241 Am within 45 min whereas the most effective system was found to be C 8 mimBr with ∼90 % of 241 Am deposited on the electrode for water miscible RTILs. To the best of our knowledge, this is the first approach ever been reported in the literature. (author)

Impact of anode substrates on electrodeposited zinc over cycling in zinc-anode rechargeable alkaline batteries

International Nuclear Information System (INIS)

Wei, Xia; Desai, Divyaraj; Yadav, Gautam G.; Turney, Damon E.; Couzis, Alexander; Banerjee, Sanjoy

2016-01-01

Electrochemical behavior of Ag, Bi, Cu, Fe, Ni and Sn substrates on zinc deposition was evaluated over battery cycling by cyclic voltammetry and electrochemical impedance spectroscopy. The effect of Bi, Cu, Ni, and Sn substrates on zinc electrodeposition during battery cycling was investigated using scanning electron microscopy and X-ray diffraction. The corrosion behavior of each metal in 9 M KOH and the corrosion rates of zinc plated on each substrate were analyzed by Tafel extrapolation method from the potentiodynamic polarization curves and electrochemical impedance spectroscopy. Although the charge-transfer resistance (R_c_t) of zinc electrodeposition is lowest on Sn, Sn eventually corrodes on cycling in alkaline media. Use of Ni as a substrate causes zinc to deteriorate on account of rapid hydrogen evolution. Bi and Cu substrates are more suitable for use as current collectors in zinc-anode alkaline rechargeable batteries because of their low corrosion rate and compact zinc deposition over battery cycling.

Structural defects in electrodeposited Ni studied by positron annihilation

International Nuclear Information System (INIS)

Vertes, A.; Szeles, C.; Czako-Nagy, I.; Lakatos-Varsanyi, M.

1982-01-01

Structural investigation of electrodeposited Ni was carried out by positron annihilation (PA) technique. Additional Moessbauer effect and X-ray diffraction measurements were also performed. The samples were produced under different plating conditions resulting in stress in the range -100 to +600 N/mm 2 . From the positron lifetime measurements it seems that the defect pattern of electrodeposited Ni samples might be substantially different from sample to sample with different deposition and plating conditions. (Auth.)

Active and inactive buffering effect on the electrochemical behavior of Sn–Ni/MWCNT composite anodes prepared by pulse electrodeposition for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Uysal, Mehmet, E-mail: mehmet_uys@yahoo.com; Cetinkaya, Tugrul; Alp, Ahmet; Akbulut, Hatem

2015-10-05

Highlights: • Sn–Ni/MWCNT anodes were produced by pulse electrodeposition. • The effect of MWCNT studied on electrochemical properties of composite electrodes. • A high reversible capacity, and good cyclability were achieved for Sn–Ni/MWCNT (10 g L{sup −1}). - Abstract: Cycling stability of pure tin electrodes was aimed to improve by using suitable combination of nickel and multiwalled carbon nanotubes (MWCNTs). Nanocrystalline Sn–Ni/MWCNT composite was prepared by ultrasonic-pulse electrodeposition on a copper substrate in a pyrophosphate bath containing different concentrations of multi-walled carbon nanotubes. Surface morphology of produced Sn–Ni/MWCNT composites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was conducted to understand the elemental surface composition of composites. X-ray diffraction analysis was carried out to investigate structure of Sn–Ni/MWCNT composites. The electrochemical performances of Sn–Ni/MWCNT composite electrodes have been investigated by charge/discharge tests, cyclic voltammetric experiments and the ac impedance technique. These cells discharge capacity cyclically tested by a battery tester at a constant current in voltage range between 0.02 V and 1.5 V. The concentrations of MWCNTs were shown to be a crucial factor to improve Sn–Ni/MWCNT composite anodes for cyclability and reversible capacity.

Facile synthesis of polypyrrole functionalized nickel foam with catalytic activity comparable to Pt for the poly-generation of hydrogen and electricity

Science.gov (United States)

Tang, Tiantian; Li, Kan; Shen, Zhemin; Sun, Tonghua; Wang, Yalin; Jia, Jinping

2016-01-01

Polypyrrole functionalized nickel foam is facilely prepared through the potentiostatic electrodeposition. The PPy-functionalized Ni foam functions as a hydrogen-evolution cathode in a rotating disk photocatalytic fuel cell, in which hydrogen energy and electric power are generated by consuming organic wastes. The PPy-functionalized Ni foam cathode exhibits stable catalytic activities after thirteen continuous runs. Compared with net or plate structure, the Ni foam with a unique three-dimensional reticulate structure is conducive to the electrodeposition of PPy. Compared with Pt-group electrode, PPy-coated Ni foam shows a satisfactory catalytic performance for the H2 evolution. The combination of PPy and Ni forms a synergistic effect for the rapid trapping and removal of proton from solution and the catalytic reduction of proton to hydrogen. The PPy-functionalized Ni foam could be applied in photocatalytic and photoelectrochemical generation of H2. In all, we report a low cost, high efficient and earth abundant PPy-functionalized Ni foam with a satisfactory catalytic activities comparable to Pt for the practical application of poly-generation of hydrogen and electricity.

Nickel-regulated heart rate variability: The roles of oxidative stress and inflammation

International Nuclear Information System (INIS)

Chuang, Hsiao-Chi; Hsueh, Tzu-Wei; Chang, Chuen-Chau; Hwang, Jing-Shiang; Chuang, Kai-Jen; Yan, Yuan-Horng; Cheng, Tsun-Jen

2013-01-01

Heart rate variability (HRV) has been reported to be a putative marker of cardiac autonomic imbalance caused by exposure to ambient particulate matter (PM). Our objective in this study was to determine the effects on HRV from exposure to nickel, an important chemical component of ambient PM that results in oxidative stress and inflammation. HRV data were collected for 72 h before lung exposure (baseline) and 72 h after intratracheal exposure (response) to nickel sulphate (NiSO 4 ; 526 μg) in Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. The antioxidant N-acetyl-L-cysteine (NAC) and the anti-inflammatory celecoxib were intraperitoneally injected to examine post-exposure oxidative and inflammatory responses. Self-controlled experiments examined the effects of NiSO 4 exposure on average normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to-normal intervals (LnSDNN) and root mean square of successive differences of adjacent normal-to-normal intervals (LnRMSSD); the resulting data were sequentially analysed using the generalised estimating equation model. HRV effects on NiSO 4 -exposed SH rats were greater than those on NiSO 4 -exposed WKY rats. After adjusted the HRV responses in the WKY rats as control, ANN and LnRMSSD were found to be quadratically increased over 72 h after exposure to NiSO 4 . Both NAC and celecoxib mitigated the NiSO 4 -induced alterations in HRV during the exposure period. The results suggest that concurrent Ni-induced oxidative stress and inflammatory responses play important roles in regulating HRV. These findings help bridge the gap between epidemiological and clinical studies on the plausible mechanisms of the cardiovascular consequences induced by chemical components in ambient PM. -- Highlights: ► To determine the effects on HRV from exposure to nickel. ► ANN and LnRMSSD were found to be quadratically increased after exposure to Ni. ► NAC and celecoxib mitigated the Ni

Nickel-regulated heart rate variability: The roles of oxidative stress and inflammation

Energy Technology Data Exchange (ETDEWEB)

Chuang, Hsiao-Chi, E-mail: r92841005@ntu.edu.tw [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Tzu-Wei, E-mail: r95841015@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, Department of Public Health, National Taiwan University, Taipei, Taiwan (China); Chang, Chuen-Chau, E-mail: nekota@tmu.edu.tw [Department of Anaesthesiology, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan (China); Hwang, Jing-Shiang, E-mail: jshwang@stat.sinica.edu.tw [Institute of Statistical Science, Academia Sinica, Taipei, Taiwan (China); Chuang, Kai-Jen, E-mail: kjc@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Yan, Yuan-Horng, E-mail: d97841006@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, Department of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Medical Research, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City, Taiwan (China); Cheng, Tsun-Jen, E-mail: tcheng@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, Department of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China)

2013-01-15

Heart rate variability (HRV) has been reported to be a putative marker of cardiac autonomic imbalance caused by exposure to ambient particulate matter (PM). Our objective in this study was to determine the effects on HRV from exposure to nickel, an important chemical component of ambient PM that results in oxidative stress and inflammation. HRV data were collected for 72 h before lung exposure (baseline) and 72 h after intratracheal exposure (response) to nickel sulphate (NiSO{sub 4}; 526 μg) in Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. The antioxidant N-acetyl-L-cysteine (NAC) and the anti-inflammatory celecoxib were intraperitoneally injected to examine post-exposure oxidative and inflammatory responses. Self-controlled experiments examined the effects of NiSO{sub 4} exposure on average normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to-normal intervals (LnSDNN) and root mean square of successive differences of adjacent normal-to-normal intervals (LnRMSSD); the resulting data were sequentially analysed using the generalised estimating equation model. HRV effects on NiSO{sub 4}-exposed SH rats were greater than those on NiSO{sub 4}-exposed WKY rats. After adjusted the HRV responses in the WKY rats as control, ANN and LnRMSSD were found to be quadratically increased over 72 h after exposure to NiSO{sub 4}. Both NAC and celecoxib mitigated the NiSO{sub 4}-induced alterations in HRV during the exposure period. The results suggest that concurrent Ni-induced oxidative stress and inflammatory responses play important roles in regulating HRV. These findings help bridge the gap between epidemiological and clinical studies on the plausible mechanisms of the cardiovascular consequences induced by chemical components in ambient PM. -- Highlights: ► To determine the effects on HRV from exposure to nickel. ► ANN and LnRMSSD were found to be quadratically increased after exposure to Ni. ► NAC and

Influence of γ-phase on corrosion resistance of Zn–Ni alloy electrodeposition from acetate electrolytic bath

Science.gov (United States)

Selvaraju, V.; Thangaraj, V.

2018-05-01

The electrodeposition of Zn–Ni alloy containing 10% to 15% nickel was deposited from acetate electrolytic bath. The effect of current density, pH, temperature, cathodic current efficiency on the deposition of Zn–Ni alloy and the throwing power ability of the solution was investigated. The composition of the deposits and the morphology were strongly influenced by the temperature and applied current density. Corrosion resistance of a Zn–Ni alloy deposit was increases with the increase of current density. Zn–Ni alloy deposits shows higher corrosion resistance at optimum current density of 3.0 A dm‑2. X-Ray diffraction measurement confirms the presence of γ –phase Zn–Ni alloy deposition. The XRD reflection of Zn–Ni (831) was found to be increased with increase in current density. SEM studies reveal that the nanovial structure of Zn–Ni alloy deposited at 3.0 A dm‑2 gives high protection against corrosion.

Electrodeposition of Actinide and Lanthanide Elements

International Nuclear Information System (INIS)

Baerring, N.E.

1966-02-01

Some deposition parameters for the quantitative electrodeposition of hydrolysis products of plutonium were qualitatively studied at trace concentrations of plutonium. The hydrogen ion concentration, the current and the electrolysis time proved to be the determining factors in the quantitative electrolytic precipitation of plutonium, while other factors such as cathode material, the pretreatment of the cathode surface, the nature of the electrolytic anion, and the oxidation state of plutonium in the starting solution were found to be of less importance. The conditions selected for quantitative electrodeposition of plutonium from slightly acid nitrate solutions on a stainless steel cathode were successfully tried also with uranium, neptunium, americium, cerium and thulium. Details of a procedure used for plating mg amounts of plutonium and neptunium on small stainless steel cylinders are also given

Electrodeposition of Actinide and Lanthanide Elements

Energy Technology Data Exchange (ETDEWEB)

Baerring, N E

1966-02-15

Some deposition parameters for the quantitative electrodeposition of hydrolysis products of plutonium were qualitatively studied at trace concentrations of plutonium. The hydrogen ion concentration, the current and the electrolysis time proved to be the determining factors in the quantitative electrolytic precipitation of plutonium, while other factors such as cathode material, the pretreatment of the cathode surface, the nature of the electrolytic anion, and the oxidation state of plutonium in the starting solution were found to be of less importance. The conditions selected for quantitative electrodeposition of plutonium from slightly acid nitrate solutions on a stainless steel cathode were successfully tried also with uranium, neptunium, americium, cerium and thulium. Details of a procedure used for plating mg amounts of plutonium and neptunium on small stainless steel cylinders are also given.

Stability of Electrodeposition at Solid-Solid Interfaces and Implications for Metal Anodes

Science.gov (United States)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-08-01

We generalize the conditions for stable electrodeposition at isotropic solid-solid interfaces using a kinetic model which incorporates the effects of stresses and surface tension at the interface. We develop a stability diagram that shows two regimes of stability: a previously known pressure-driven mechanism and a new density-driven stability mechanism that is governed by the relative density of metal in the two phases. We show that inorganic solids and solid polymers generally do not lead to stable electrodeposition, and provide design guidelines for achieving stable electrodeposition.

Development of nickel-hydrogen battery for electric vehicle; Denki jidoshayo nickel-suiso denchi no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Research and development of battery, a main part of electric vehicle, have been promoted. Various batteries, such as lead battery, nickel-cadmium battery, nickel-hydrogen battery, lithium ion battery and so on, have been investigated for electric vehicles. Among these, nickel-hydrogen battery is superior to the others from the points of energy density, lifetime, low-temperature properties, and safety. It is one of the most prospective batteries for electric vehicle. Research and development of the nickel-hydrogen battery with higher energy density and longer lifetime have been promoted for the practical application by Tohoku Electric Power Co., Inc. This article shows main performance of the developed nickel-hydrogen battery for electric vehicle. The nominal voltage is 12 V, the rated capacity is 125 Ah, the outside dimension is L302{times}W170{times}H245 mm, the weight is 25.5 kg, the energy density is 60 Wh/kg, the output density is 180 W/kg, and the available environment temperature is between -20 and 60 {degree}C. 1 fig., 1 tab.

Ultrasonic electrodeposition of silver nanoparticles on dielectric silica spheres

International Nuclear Information System (INIS)

Tang Shaochun; Tang Yuefeng; Gao Feng; Liu Zhiguo; Meng Xiangkang

2007-01-01

In the present study, a facile and one-step ultrasonic electrodeposition method is first applied to controllably coat colloidal silica spheres with silver nanoparticles. This method is additive-free and very direct, because processes necessary in many other approaches, such as pretreatment of the silica sphere surface and pre-preparation of silver nanoparticles, are not involved in it. Furthermore, it makes possible the coating of dielectric substrates with metal through an electrodeposition route. Under appropriate conditions, silver nanoparticles with sizes of 8-10 nm in diameter can be relatively homogeneously deposited onto the surface of preformed colloidal silica spheres. Silver particles with different sizes and dispersive uniformity on silica sphere surfaces can also be obtained by adjusting the current density (I), the concentration of electrolyte (C) and the electrolysis time (t). The possible ultrasonic electrodeposition mechanism is also suggested according to the experimental results

The electrodeposition of niobium on tungsten

International Nuclear Information System (INIS)

Taylor, R.G.

1977-03-01

The electrodeposition of niobium on a tungsten substrate has been demonstrated by electrolysis of an alkali metal fluoride melt. The deposit produced was non-porous, coherent and formed a good bond to the substrate. (author)

Synthesis, structure characterization and catalytic activity of nickel tungstate nanoparticles

Science.gov (United States)

Pourmortazavi, Seied Mahdi; Rahimi-Nasrabadi, Mehdi; Khalilian-Shalamzari, Morteza; Zahedi, Mir Mahdi; Hajimirsadeghi, Seiedeh Somayyeh; Omrani, Ismail

2012-12-01

Taguchi robust design was applied to optimize experimental parameters for controllable, simple and fast synthesis of nickel tungstate nanoparticles. NiWO4 nanoparticles were synthesized by precipitation reaction involving addition of nickel ion solution to the tungstate aqueous reagent and then formation of nickel tungstate nucleolus which are insoluble in aqueous media. Effects of various parameters such as nickel and tungstate concentrations, flow rate of reagent addition and reactor temperature on diameter of synthesized nickel tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The results for analysis of variance (ANOVA) showed that particle size of nickel tungstate can be effectively tuned by controlling significant variables involving nickel and tungstate concentrations and flow rate; while, temperature of the reactor has a no considerable effect on the size of NiWO4 particles. The ANOVA results proposed the optimum conditions for synthesis of nickel tungstate nanoparticles via this technique. Also, under optimum condition nanoparticles of NiWO4 were prepared and their structure and chemical composition were characterized by means of EDAX, XRD, SEM, FT-IR spectroscopy, UV-vis spectroscopy, and photoluminescence. Finally, catalytic activity of the nanoparticles in a cycloaddition reaction was examined.

Nickel in nails, hair and plasma from nickel-hypersensitive women

DEFF Research Database (Denmark)

Gammelgaard, Bente; Veien, Niels

1990-01-01

The concentrations of nickel in finger-nails, toe-nails, hair and plasma from 71 nickel-hypersensitive women and 20 non-hypersensitive women were determined. Nickel concentrations in finger-nails were significantly higher than in toe-nails in both the nickel-hypersensitive group and the control...... group. Nickel-sensitive women had significantly higher levels of nickel in toe-nails, hair and plasma than had control subjects, whereas there was no significant difference in nickel concentration in finger-nails between the two groups. No correlation could be demonstrated between nickel levels in any...... combination of nails, hair and plasma in the nickel-hypersensitive or in the control group....

Nickel Nanowire@Porous NiCo{sub 2}O{sub 4} Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

Energy Technology Data Exchange (ETDEWEB)

Wan, Houzhao; Li, Lang; Zhang, Jun; Liu, Xiang; Wang, Hanbin; Wang, Hao, E-mail: nanoguy@126.com [Faculty of Physics and Electronic Science, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Laboratory of Ferro & Piezoelectric Materials and Devices, Hubei University, Wuhan (China)

2017-12-13

A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo{sub 2}O{sub 4} nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo{sub 2}O{sub 4} nanorods and construct the well-defined NiCo{sub 2}O{sub 4} nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo{sub 2}O{sub 4}/Ni foam electrode shows a high areal specific capacitance (7.4 F cm{sup −2} at 5 mA cm{sup −2}), excellent rate capability (88.04% retained at 100 mA cm{sup −2}), and good cycling stability (74.08% retained after 1,500 cycles). The superior electrochemical properties made it promising as electrode for supercapacitors.

The effect of different component ratios in block polymers and processing conditions on electrodeposition efficiency onto titanium

Energy Technology Data Exchange (ETDEWEB)

Fukuhara, Yusuke; Kyuzo, Megumi [Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Tsutsumi, Yusuke [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Nagai, Akiko [Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Chen, Peng [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Hanawa, Takao, E-mail: hanawa.met@tmd.ac.jp [Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan)

2015-11-15

Graphical abstract: - Highlights: • MPC polymers with an ability of electrodeposition were synthesized. • MPC polymers were immobilized on titanium substrates by electrodeposition. • Immobilization by electrodeposition of MPC polymer decreased water contact angle and protein adsorption. • Length of MPC unit and electrodeposition time did not influence water contact angle and protein adsorption. - Abstract: 2-Methacryloyloxyethyl phosphorylcholine (MPC) polymers for electrodeposition to titanium surfaces were synthesized. The polymers were block-type copolymers composed of a poly(MPC) segment and a poly(2-aminoethylmethacrylate (AEMA)) segment, which could electronically adsorb to a titanium oxide film on the titanium surface. The polymer was synthesized as expected by nuclear magnetic resonance and gel permeation chromatography. In a 0.26 mmol L{sup −1} PMbA solution adjusted to pH 11, −3.0 V (vs. an Ag/AgCl electrode) was applied to a titanium substrate for 300 s. We evaluated the effects of the molecular structure of poly(MPC-block-AEMA) (PMbA) with a different polymerization degree of MPC unit, whereas the polymerization degree of the AEMA units was fixed. The 15-min electrodeposition of PMbA100 was the most efficient condition in this study. On the other hand, the results of the water contact angle and the amount of adsorbed protein did not change, even when altering the MPC unit number and electrodeposition time. This indicates that the immobilization by electrodeposition of PMbA is important for the inhibition of protein adsorption, while the polymerization degree of the MPC unit and the electrodeposition time do not influence them. This study will enhance the understanding of effective polymer structures for electrodeposition and electrodeposition conditions.

Analysis of continuous solvent extraction of nickel from spent electroless nickel plating baths by a mixer-settler

Energy Technology Data Exchange (ETDEWEB)

Huang, Ying, E-mail: huang-ying@aist.go.jp [Metals Recycling Group, Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan); Tanaka, Mikiya, E-mail: mky-tanaka@aist.go.jp [Metals Recycling Group, Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan)

2009-05-30

It is urgent to develop an effective technique to treat the large amount of spent electroless nickel plating bath and recycle the high concentration nickel. In our previous study, high recycling efficiency of nickel from the model spent bath was obtained by continuous solvent extraction with 2-hydroxy-5-nonylacetophenone oxime (LIX84I) as the extractant and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) as the accelerator using a mixer-settler extractor. It was observed that the extraction efficiency was affected by the operation parameters such as the flow rates of the aqueous and organic phases and the total stage number. In the present study, the effects of the operation parameters on the extraction efficiency were quantitatively studied on the basis of the pseudo-first-order interfacial extraction rate equation together with the hydrodynamic properties in the mixer. The organic phase holdup, measured under varying conditions of the flow rates of both phases, was analyzed by the Takahashi-Takeuchi holdup model in order to estimate the specific interfacial area. The overall extraction rate coefficients defined by the product of the interfacial extraction rate constant and the specific interfacial area were evaluated using the experimental data and ranged from 3.5 x 10{sup -3} to 6.7 x 10{sup -3} s{sup -1}, which was close to the value of 3.4 x 10{sup -3} s{sup -1} obtained by batch extraction. Finally, an engineering simulation method was established for assessing the extraction efficiency of nickel during a multistage operation.

Analysis of continuous solvent extraction of nickel from spent electroless nickel plating baths by a mixer-settler

International Nuclear Information System (INIS)

Huang, Ying; Tanaka, Mikiya

2009-01-01

It is urgent to develop an effective technique to treat the large amount of spent electroless nickel plating bath and recycle the high concentration nickel. In our previous study, high recycling efficiency of nickel from the model spent bath was obtained by continuous solvent extraction with 2-hydroxy-5-nonylacetophenone oxime (LIX84I) as the extractant and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) as the accelerator using a mixer-settler extractor. It was observed that the extraction efficiency was affected by the operation parameters such as the flow rates of the aqueous and organic phases and the total stage number. In the present study, the effects of the operation parameters on the extraction efficiency were quantitatively studied on the basis of the pseudo-first-order interfacial extraction rate equation together with the hydrodynamic properties in the mixer. The organic phase holdup, measured under varying conditions of the flow rates of both phases, was analyzed by the Takahashi-Takeuchi holdup model in order to estimate the specific interfacial area. The overall extraction rate coefficients defined by the product of the interfacial extraction rate constant and the specific interfacial area were evaluated using the experimental data and ranged from 3.5 x 10 -3 to 6.7 x 10 -3 s -1 , which was close to the value of 3.4 x 10 -3 s -1 obtained by batch extraction. Finally, an engineering simulation method was established for assessing the extraction efficiency of nickel during a multistage operation.

Analysis of continuous solvent extraction of nickel from spent electroless nickel plating baths by a mixer-settler.

Science.gov (United States)

Huang, Ying; Tanaka, Mikiya

2009-05-30

It is urgent to develop an effective technique to treat the large amount of spent electroless nickel plating bath and recycle the high concentration nickel. In our previous study, high recycling efficiency of nickel from the model spent bath was obtained by continuous solvent extraction with 2-hydroxy-5-nonylacetophenone oxime (LIX84I) as the extractant and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) as the accelerator using a mixer-settler extractor. It was observed that the extraction efficiency was affected by the operation parameters such as the flow rates of the aqueous and organic phases and the total stage number. In the present study, the effects of the operation parameters on the extraction efficiency were quantitatively studied on the basis of the pseudo-first-order interfacial extraction rate equation together with the hydrodynamic properties in the mixer. The organic phase holdup, measured under varying conditions of the flow rates of both phases, was analyzed by the Takahashi-Takeuchi holdup model in order to estimate the specific interfacial area. The overall extraction rate coefficients defined by the product of the interfacial extraction rate constant and the specific interfacial area were evaluated using the experimental data and ranged from 3.5 x 10(-3) to 6.7 x 10(-3)s(-1), which was close to the value of 3.4 x 10(-3)s(-1) obtained by batch extraction. Finally, an engineering simulation method was established for assessing the extraction efficiency of nickel during a multistage operation.

Microstructure and tribological property of nanocrystalline Co–W alloy coating produced by dual-pulse electrodeposition

International Nuclear Information System (INIS)

Su Fenghua; Huang Ping

2012-01-01

Highlights: ► The nanocrystalline Co–W alloy coating were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate. ► The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of electrodeposited Co–W alloy coatings were established. ► By careful control of the electrodeposition condition and the bath composition, the Co–W alloy coating excellent performance of microhardness and tribological properties, can exhibit excellent performances of microhardness and tribological properties. - Abstract: The nanocrystalline Co–W alloy coatings were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate (Na 2 WO 4 ). Influence of the current density and Na 2 WO 4 concentration in bath on the microstructure, morphology and hardness of the Co–W alloy coatings were investigated using an X-ray diffraction, a scanning electronic microscope and a Vickers hardness tester, respectively. In addition, the friction and wear properties of the Co–W alloy coating electrodeposited under different condition were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of the deposited Co–W alloy coatings were discussed in detail. The results showed that the microhardness of the deposited Co–W alloy coating was significantly affected by its average grain size, W content and crystal orientation. Smaller grain size, higher W content and strong hcp (1 0 0) orientation favor the improvement of the hardness for Co–W alloy coatings. The deposited Co–W alloy coating could obtain the maximum microhardness over 1000 kgf mm −2 by careful control of the electrodeposition conditions. The tribological properties of the electrodeposited Co–W alloy coating were greatly

Non-Cyanide Electrodeposited Ag–PTFE Composite Coating Using Direct or Pulsed Current Deposition

Directory of Open Access Journals (Sweden)

Raymond Sieh

2016-07-01

Full Text Available The effects of FC-4 cationic surfactant on electrodeposited Ag–PTFE composite coating using direct or pulsed currents were studied using scanning electron microscope (SEM, energy dispersive X-ray (EDS, optical microscope, and a linear tribometer. FC-4:PTFE in various ratios were added to a non-cyanide succinimide silver complex bath. Direct or pulsed current method was used at a constant current density to enable comparison between both methods. A high incorporation rate of PTFE was successfully achieved, with pulsed current being highly useful in increasing the amount of PTFE in the composite coating. The study of coating wear under sliding showed that a large majority of the electrodeposited coatings still managed to adhere to the substrate, even after 10 wear cycles of sliding tests. Performance improvements were achieved on all the samples with a coefficient of friction (CoF between 0.06 and 0.12.

Adsorption of organic layers over electrodeposited magnetite (Fe3O4) thin films

International Nuclear Information System (INIS)

Cortes, M.; Gomez, E.; Sadler, J.; Valles, E.

2011-01-01

Research highlights: → Adherent low roughness magnetite films ranging from 80 nm to 3.75 μm-thick were electrodeposited on Au/glass substrates under galvanostatic control. → X-ray diffraction and magnetic measurements corroborates the purity of the electrodeposited magnetite. → Both dodecanethiol and oleic acid are shown to adsorb on the magnetite prepared at low temperature, significantly inducing the hydrophobicity of the surface. → Contact angle and voltammetric measurements, as well as XPS confirm the monolayers formation. - Abstract: The formation of monolayers of two organic compounds (oleic acid and dodecanethiol) over magnetite films was studied. Magnetite films ranging from 80 nm to 3.75 μm-thick were electrodeposited on Au on glass substrates under galvanostatic control, with deposition parameters optimized for minimum surface roughness. Films were characterised by SEM and AFM, showing granular deposits with a low rms roughness of 5-40 nm measured over an area of 1 μm 2 . The growth rate was estimated by measuring cross-sections of the thin films. Pure magnetite with an fcc structure is observed in XRD diffractograms. The adsorption of both oleic acid and dodecanethiol on the magnetite films was tested by immersing them in ethanol solutions containing the organic molecules, for different deposition time, temperature and cleaning procedure. Monolayer formation in both cases was studied by contact angle and voltammetric measurements, as well as XPS.

Electrodeposition of polyfluorene on a carbon nanotube electrode

International Nuclear Information System (INIS)

Valentini, L; Mengoni, F; Mattiello, L; Kenny, J M

2007-01-01

Electrophoretically deposited single-walled carbon nanotube (SWCNT) films on a transparent conducting surface are used as electrodes for the electrodeposition of a π-conjugated polymer formed by the oxidative coupling of fluorene units. This method provides a uniform coverage of the conducting surface with respect to SWCNTs chemically assembled on a gold substrate. Electron microscopy reveals the formation of a polymer-SWCNT nanostructure which imparts distinct electrical properties from those of the polymer electrodeposited on the neat electrode. By combining the attractive properties of SWCNTs and polyfluorene, these nanocomposites open up new opportunities to achieve electrical contacts in nano- to micro-devices

Composition control of tin-zinc electrodeposits through means of experimental strategies

International Nuclear Information System (INIS)

Dubent, S.; De Petris-Wery, M.; Saurat, M.; Ayedi, H.F.

2007-01-01

Tin-zinc coatings offer excellent corrosion protection and do not suffer the drawback of the voluminous white corrosion product of pure zinc or high zinc alloy coatings. The aim of this study was to determine the suitable electroplating conditions (i.e. electrolyte composition and cathode current density) to produce 70Sn-30Zn electrodeposits. Thus, a fractional factorial design (FFD) was carried out to evaluate the effects of experimental parameters (Zn II concentration, Sn IV concentration, pH and current density) on the Zn content of the electrodeposit. On the other hand, the electrodeposits were characterised by glow discharge optical emission spectroscopy (GDOES) and scanning electron microscopy (SEM). Correlation between operating conditions, composition and morphology was attempted

Austenitic stainless steel alloys with high nickel contents in high temperature liquid metal systems

International Nuclear Information System (INIS)

Konvicka, H.R.; Schwarz, N.F.

1981-01-01

Fe-Cr-Ni base alloys (nickel content: from 15 to 70 wt%, Chromium content: 15 wt%, iron: balance) together with stainless steel (W.Nr. 1.4981) have been exposed to flowing liquid sodium at 730 0 C in four intervals up to a cumulative exposure time of 1500 hours. Weight change data and the results of post-exposition microcharacterization of specimens are reported. The corrosion rates increase with increasing nickel content and tend to become constant after longer exposure times for each alloy. The corrosion rate of stainless steel is considerably reduced due to the presence of the base alloys. Different kinetics of nickel poor (up to 35% nickel) and nickel rich (> 50% nickel) alloys and nickel transport from nickel rich to nickel poor material is observed. (orig.)

Electrochemical Properties of Graphene-vanadium Oxide Composite Prepared by Electro-deposition for Electrochemical Capacitors

International Nuclear Information System (INIS)

Jeong, Heeyoung; Jeong, Sang Mun

2015-01-01

The nanostructural graphene/vanadium oxide (graphene/V 2 O 5 ) composite with enhanced capacitance was synthesized by the electro-deposition in 0.5 M VOSO 4 solution. The morphology of composites was characterized using scanning electron microscopy (SEM), x-ray diffraction pattern (XRD), and x-ray photoelectron spectroscopy (XPS). The oxidation states of the electro-deposited vanadium oxide was found to be V 5+ and V 4+ . The morphology of the prepared graphene/V 2 O 5 composite exhibits a netlike nano-structure with V 2 O 5 nanorods in about 100 nm diameter, which could lead a better contact between electrolyte an electrode. The composite with a deposition time of 4,000 s exhibits the specific capacitance of 854 mF/cm 2 at a scan rate of 20 mV/s and the capacitance retention of 53% after 1000 CV cycles

SILVER RECYCLING FROM PHOTO-PROCESSING WASTE USING ELECTRODEPOSITION METHOD

Directory of Open Access Journals (Sweden)

Mochammad Feri Hadiyanto

2010-06-01

Full Text Available Silver electrodeposition of photo-processing waste and without addition of KCN 1,0 M has been studied for silver recycling. Photo procesing waste containing silver in form of [Ag(S2O32]3- was electrolysed at constant potential and faradic efficiency was determined at various of electrolysis times. Electrolysis of 100 mL photo processing waste without addition of KCN 1,0 M was carried out at constant potential 1.20 Volt, while electrolysis 100 mL photo procesing waste with addition of 10 mL KCN 1,0 M electrolysis was done at 1.30 Volt.The results showed that for silver electrodeposition from photo processing waste with addition of KCN 1,0 M was more favorable with faradic efficiency respectively were 93,16; 87,02; 74,74 and 78,35% for 30; 60; 90 and 120 minutes of electrolysis.   Keywords: Silver extraction, electrodeposition, photo-processing waste

Nucleation and growth mechanism of Co–Pt alloy nanowires electrodeposited within alumina template

Energy Technology Data Exchange (ETDEWEB)

Srivastav, Ajeet K., E-mail: srivastav.ajeet.kumar@gmail.com, E-mail: mm09d004@smail.iitm.ac.in [Indian Institute of Technology Madras, Department of Metallurgical and Materials Engineering (India); Shekhar, Rajiv [Indian Institute of Technology Kanpur, Department of Materials Science and Engineering (India)

2015-01-15

Co–Pt alloy nanowires were electrodeposited by direct current electrodeposition within nanoporous alumina templates with varying deposition potentials. The effect of deposition potential on nucleation and growth mechanisms during electrodeposition of Co–Pt alloy nanowires was investigated. The less negative deposition potential (−0.9 V) favours the instantaneous nucleation mechanism. The positive deviation from theoretical instantaneous and progressive nucleation mechanisms occurs at higher negative deposition potentials. The hysteresis behaviour and magnetic properties of electrodeposited Co–Pt alloy nanowires altered with varying deposition potential. The easy magnetization direction was in direction perpendicular to the wire axis. The deposition potential dependent change in hysteresis behaviour with increased coercivity and scattered remanence ratio was observed. This is attributed to better crystallinity with reduced defect density and hydrogen evolution causing structural changes at more negative deposition potentials.

Single potential electrodeposition of nanostructured battery materials for lithium-ion batteries

Science.gov (United States)

Mosby, James Matthew

lithiated and delithiated similarly to Cu2Sb synthesized with different techniques. The deposition of Cu2Sb onto TEM grids was used for the first time without binder to characterize the morphology, composition and crystallinity changes that occur during the lithiation and delithiation of Cu2Sb. Superior capacity retention and rate performance was achieved with Cu2Sb electrodeposited onto high surface area copper foil. This superior performance demonstrates the improvement in battery performance that is expected from Cu2Sb nanowires, which have an order of magnitude higher surface area relative to the copper foam.

Unified Hall-Petch description of nano-grain nickel hardness, flow stress and strain rate sensitivity measurements

Science.gov (United States)

Armstrong, R. W.; Balasubramanian, N.

2017-08-01

It is shown that: (i) nano-grain nickel flow stress and hardness data at ambient temperature follow a Hall-Petch (H-P) relation over a wide range of grain size; and (ii) accompanying flow stress and strain rate sensitivity measurements follow an analogous H-P relationship for the reciprocal "activation volume", (1/v*) = (1/A*b) where A* is activation area. Higher temperature flow stress measurements show a greater than expected reduction both in the H-P kɛ and in v*. The results are connected with smaller nano-grain size (tested at very low imposed strain rates.

Chemical nickel plating in tartrate solutions with borohydride reducing agent

International Nuclear Information System (INIS)

Plokhov, V.A.

1986-01-01

The authors investigate the influence of various factors on the rate of chemical nickel plating in strongly alkaline tartrate solutions with a borohydride reducing agent. After 30 min of the process of nickel plating, the final concentration of sodium borohydride decreases to 0.26 g/liter, leading to stoppage of the process. The nickel plating process can be intensified by increasing the concentration of sodium hydroxide in the solution, suppressing hydrolysis of borohydride, and also by introducing additives which suppress hydrolysis of borohydride. For chemical deposition of nickel-boron coatings from tartrate solutions the authors recommend the following composition (g/liter): nickel chloride 15-25, Rochelle salt 450-550, sodium hydroxide 140-160, sodium borohydride 0.8-1.0, thallium nitrate 0.003-0.008. The process temperature is 92-95 C, and the deposition rate is 4-6 um/h

Electrodeposition of Isolated Platinum Atoms and Clusters on Bismuth-Characterization and Electrocatalysis.

Science.gov (United States)

Zhou, Min; Dick, Jeffrey E; Bard, Allen J

2017-12-06

We describe a method for the electrodeposition of an isolated single Pt atom or small cluster, up to 9 atoms, on a bismuth ultramicroelectrode (UME). This deposition was immediately followed by electrochemical characterization via the hydrogen evolution reaction (HER) that occurs readily on the electrodeposited Pt but not on Bi. The observed voltammetric current plateau, even for a single atom, which behaves as an electrode, allows the estimation of deposit size. Pt was plated from solutions of femtomolar PtCl 6 2- , which allowed precise control of the arrival of ions and thus the plating rate on the Bi UME, to one ion every few seconds. This allowed the atom-by-atom fabrication of isolated platinum deposits, ranging from single atoms to 9-atom clusters. The limiting currents in voltammetry gave the size and number of atoms of the clusters. Given the stochasticity of the plating process, we show that the number of atoms plated over a given time (10 and 20 s) follows a Poisson distribution. Taking the potential at a certain current density as a measure of the relative rate of the HER, we found that the potential shifted positively as the size increased, with single atoms showing the largest overpotentials compared to bulk Pt.

Morphology selection for cupric oxide thin films by electrodeposition.

Science.gov (United States)

Dhanasekaran, V; Mahalingam, T; Chandramohan, R

2011-10-01

Polycrystalline cupric oxide thin films were deposited using alkaline solution bath employing cathodic electrodeposition method. The thin films were electrodeposited at various solution pH. The surface morphology and elemental analyzes of the films were studied using scanning electron microscopy (SEM) and energy dispersive X-ray analysis, respectively. SEM studies revealed that the surface morphology could be tailored suitably by adjusting the pH value during deposition. Mesh average on multiple lattice mode atomic force microscopy image was obtained and reported. Copyright © 2011 Wiley-Liss, Inc.

On texture formation of chromium electrodeposits

DEFF Research Database (Denmark)

Nielsen, Christian Bergenstof; Leisner, Peter; Horsewell, Andy

1998-01-01

The microstructure, texture and hardness of electrodeposited hard, direct current (DC) chromium and pulsed reversed chromium has been investigated. These investigations suggest that the growth and texture of hard chromium is controlled by inhibition processes and reactions. Further, it has been...

Phosphate tuned copper electrodeposition and promoted formic acid selectivity for carbon dioxide reduction

DEFF Research Database (Denmark)

Zhao, Jian; Sun, Libo; Canepa, Silvia

2017-01-01

Fabrication of catalytically active electrodes by electrodeposition is attractive due to its in situ nature, easy controllability, and large-scale operation capability. Most recently, modifying the electrodes with phosphate ligands through electrodepositing electrode materials has shown promising...

Effect of Electrodeposition Potential on Composition of CuIn1−xGaxSe2 Absorber Layer for Solar Cell by One-Step Electrodeposition

OpenAIRE

You, Rui-Wei; Lew, Kar-Kit; Fu, Yen-Pei

2014-01-01

CIGS polycrystalline thin films were successfully fabricated by one-step cathodic electrodeposition on Mo-coated glass. In this study, we applied a galvanometry mode with three-electrode potentiostatic systems to produce a constant concentration electroplating solution, which were composed of CuCl2, InCl3, GaCl3, and SeO2. Then these as-electrodeposited films were annealed in argon atmosphere and characterized by X-ray diffraction. The results revealed that annealing treatment significantly i...

Nickel-induced cytokine production from mononuclear cells in nickel-sensitive individuals and controls. Cytokine profiles in nickel-sensitive individuals with nickel allergy-related hand eczema before and after nickel challenge

DEFF Research Database (Denmark)

Borg, L; Christensen, J M; Kristiansen, J

2000-01-01

Exposure to nickel is a major cause of allergic contact dermatitis which is considered to be an inflammatory response induced by antigen-specific T cells. Here we describe the in vitro analysis of the nickel-specific T-cell-derived cytokine response of peripheral blood mononuclear cells from 35...... was somewhat of a surprise, since previous studies have suggested a Th1 response in nickel-mediated allergic contact dermatitis. Subsequently, the nickel-allergic individuals were randomized to experimental exposure to nickel or vehicle in a double-blind design. A daily 10-min exposure of one finger to 10 ppm...... nickel solution for 1 week followed by 100 ppm for an additional week evoked a clinical response of hand eczema in the nickel-exposed group. Blood samples were drawn on days 7 and 14 after the start of this exposure to occupationally relevant concentrations of nickel. No statistically significant...

Chirality of magneto-electrodeposited metal film electrodes

International Nuclear Information System (INIS)

Mogi, Iwao; Watanabe, Kazuo

2008-01-01

The chiral electrode behaviors of magneto-electrodeposited (MED) Ag and Cu films were examined for the electrochemical reactions of D-glucose, L-glucose and L-cysteine. The Ag and Cu films were electrodeposited under a magnetic field of 2 T parallel (+2 T) or antiparallel (-2 T) to the faradaic current. For MED films of both Ag and Cu, the oxidation current of L-glucose was larger than that of D-glucose on the +2 T-film electrodes, and the results were opposite on the - 2 T-film electrodes. These facts demonstrate that the MED metal films possess the ability of chiral recognition for D- and L-glucoses. The MED Ag film electrodes also exhibited chiral behavior for the oxidation of L-cysteine

Nickel recycling in the United States in 2004

Science.gov (United States)

Goonan, Thomas G.

2009-01-01

As one of a series of reports that describe the recycling of metal commodities in the United States, this report discusses the flow of nickel from production through distribution and use, with particular emphasis on the recycling of industrial scrap (new scrap) and used products (old scrap) in 2004. This materials flow study includes a description of nickel supply and demand for the United States to illustrate the extent of nickel recycling and to identify recycling trends. Understanding how materials flow from a source through disposition can aid in improving the management of natural resource delivery systems. In 2004, the old scrap recycling efficiency for nickel was estimated to be 56.2 percent. In 2004, nickel scrap consumption in the United States was as follows: new scrap containing 13,000 metric tons (t) of nickel (produced during the manufacture of products), 12 percent; and old scrap containing 95,000 t of nickel (articles discarded after serving a useful purpose), 88 percent. The recycling rate for nickel in 2004 was 40.9 percent, and the percentage of nickel in products attributed to nickel recovered from nickel-containing scrap was 51.6 percent. Furthermore, U.S. nickel scrap theoretically generated in 2004 had the following distribution: scrap to landfills, 24 percent; recovered and used scrap, 50 percent; and unaccounted for scrap, 26 percent. Of the 50 percent of old scrap generated in the United States that was recovered and then used in 2004, about one-third was exported and two-thirds was consumed in the domestic production of nickel-containing products.

Fabrication of vertically aligned Pd nanowire array in AAO template by electrodeposition using neutral electrolyte

Directory of Open Access Journals (Sweden)

Yüzer Hayrettin

2010-01-01

Full Text Available Abstract A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current–time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM, energy-dispersive X-ray (EDX methods and X-Ray diffraction (XRD. It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially.

Effects of melt-temperature on limiting current density in Al electrodeposition and morphology of Al electrodeposits obtained from ambient temperature type molten salt; Joongata yoyuen kara no denki aluminium mekki no genkai denryu mitsudo oyobi denseki keitai ni oyobosu mekki ekion no eikyo

Energy Technology Data Exchange (ETDEWEB)

Shimizu, T.; Tatano, M.; Uchida, Y. [Nisshin Steel Co. Ltd., Tokyo (Japan)

1996-03-31

Some of more important electrolytic solutions for Al electrodeposition are organic solvents, high-temperature type molten salts and low-temperature type molten salts having a melting point of 30{degree}C or lower, such as ethylmethylimidazolium chloride (EMIC). This study uses a molten salt of AlCl3-EMIC as the low-temperature type solution for high-speed electrodeposition. Discussed herein are the effects of melt temperature on limiting current density in Al electrodeposition and Al electrodeposit morphology. Limiting current density increases as melt temperature increases at any AlCl3 concentration used in this study. The AlCl3 concentration that gives the maximum limiting current density shifts from 64 to 67mol% at a melt temperature of 120{degree}C. A dense, smooth Al electrodeposited film results at a melt temperature of 100{degree}C or lower, but the electrodeposited grains become coarser as melt temperature increases. Melt temperature can be increased to 140{degree}C to secure a smooth electrodeposited film, showing possibility of 2 times faster electrodeposition than the conventional one. 21 refs., 12 figs., 1 tab.

Chemoorganotrophic Bioleaching of Olivine for Nickel Recovery

Directory of Open Access Journals (Sweden)

Yi Wai Chiang

2014-06-01

Full Text Available Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement in the fungal growth rate, to the promotion of particle degradation, and to the detachment of the stagnant biofilm around the particles. Furthermore, ultrasonic conditioning enhanced the selectivity of A. niger for nickel over iron to a value of 3.5. Pre-carbonating the olivine mineral, to enhance mineral liberation and change metal speciation, was also attempted, but did not result in improvement as a consequence of the mild pH of chemoorganotrophic bioleaching.

Laser ablation deposition measurements from silver and nickel

DEFF Research Database (Denmark)

Svendsen, Winnie Edith; Ellegaard, Ole; Schou, Jørgen

1996-01-01

The deposition rate for laser ablated metals has been studied in a standard geometry for fluences up to 20 J/cm(2). The rate for silver and nickel is a few percent of a monolayer per pulse at the laser wavelengths 532 nm and 355 nm. The rate for nickel is significantly higher than that for silver...... at 532 nm, whereas the rate for the two metals is similar at 355 nm. This behaviour disagrees with calculations based on the thermal properties at low intensities as well as predictions based on formation of an absorbing plasma at high intensities. The deposition rate falls strongly with increasing...

Structure characterization of nanocrystalline Ni–W alloys obtained by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Indyka, P., E-mail: paulina.indyka@uj.edu.pl [Jagiellonian University, Faculty of Chemistry, 3 Ingardena St., 30-059 Krakow (Poland); Beltowska-Lehman, E.; Tarkowski, L.; Bigos, A. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); García-Lecina, E. [Surface Finishing Department, CIDETEC-IK4 – Centre for Electrochemical Technologies, P° Miramón 196, 20009 Donostia-San Sebastián (Spain)

2014-03-25

Highlights: • Ni–W alloy coatings were electrodeposited from an aqueous electrolyte solutions. • The microstructure was studied with respect to electrodeposition process parameters. • We report optimal plating conditions for crack-free, nanocrystalline Ni–W coatings. • Crystalline Ni–W coatings exhibited the phase structure of an α-Ni(W) solid solution. • Coatings revealed tensile residual stresses and weakly pronounced 〈1 1 0〉 fiber texture. -- Abstract: Ni–W coatings of different tungsten content (2–50 wt%) were electrodeposited on a steel substrates from an aqueous complex sulfate–citrate galvanic baths, under controlled hydrodynamic conditions in a Rotating Disk Electrode (RDE) system. The optimum conditions for the electrodeposition of crack-free, homogeneous nanocrystalline Ni–W coatings were determined on the basis of the microstructure investigation results. The XRD structural characterizations of Ni–W alloy coatings obtained under different experimental conditions were complemented by SEM and TEM analysis. Results of the study revealed that the main factor influencing the microstructure formation of the Ni–W coatings is the chemical composition of an electrolyte solution. X-ray and electron diffraction patterns of all nanocrystalline Ni–W coatings revealed mainly the fcc phase structure of an α-Ni(W) solid solution with a lattice parameter increased along with tungsten content. The use of additives in the plating bath resulted in the formation of equiaxial/quasifibrous, nanocrystalline Ni–W grains of an average size of about 10 nm. The coatings were characterized by relatively high tensile residual stresses (500–1000 MPa), depending on the electrodeposition conditions. Ni–W coatings exhibited weakly pronounced fiber type 〈1 1 0〉 crystallographic texture, consistent with the symmetry of the plating process. Coatings of the highest tungsten content 50 wt% were found to be amorphous.

Hydrogen absorption kinetics of niobium with an ion-plated nickel overlayer

International Nuclear Information System (INIS)

Nakamura, K.

1981-01-01

The hydrogen absorption rate for nickel-ion-plated niobium was measured as a function of hydrogen pressure and temperature. The observed absorption curves of c(mean)/csub(e) against time (c(mean) and csub(e) are the mean and equilibrium hydrogen concentrations respectively) exhibited a marked hydrogen pressure dependence below 628 K but this was less marked above 723 K. The results were analysed on the basis of the proposed model that the rate-determining step is the hydrogen permeation through the nickel overlayer and that the permeation is driven by the hydrogen activity difference between the two interfaces, namely the H 2 -Ni and Ni-Nb interfaces. The marked pressure dependence can be attributed to the fact that the hydrogen activity coefficient in nickel is constant and that in niobium it varies markedly with concentration, i.e. with hydrogen pressure and temperature. It was also found that the change in the nickel overlayer structure caused by the dilatation of bulk niobium during hydrogen absorption enhances the hydrogen absorption rates. The temperature dependence of the hydrogen absorption rate is also discussed in comparison with that for tantalum with a vacuum-deposited nickel overlayer. (Auth.)

The effect of cysteine on electrodeposition of gold nanoparticle

International Nuclear Information System (INIS)

Dolati, A.; Imanieh, I.; Salehi, F.; Farahani, M.

2011-01-01

Highlights: → Cysteine was found as an appropriate additive for electrodeposition of gold nanoparticles. → The deposition mechanism of gold nanoparticle was determined as instantaneous nucleation. → Oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits. - Abstract: The most applications of gold nanoparticles are in the photo-electronical accessories and bio-chemical sensors. Chloride solution with cysteine additive was used as electrolyte in gold nanoparticles electrodeposition. The nucleation and growing mechanism were studied by electrochemical techniques such as cyclic voltammetry and chronoamperometry, in order to obtain a suitable nano structure. The deposition mechanism was determined as instantaneous nucleation and the dimension of particles was controlled in nanometric particle size range. Atomic Force Microscope was used to evaluate the effect of cysteine on the morphology and topography of gold nanoparticles. Finally the catalytic property of gold nanoparticle electrodeposited was studied in KOH solution, where oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits.

Reaction and nucleation mechanisms of copper electrodeposition on disposable pencil graphite electrode

Energy Technology Data Exchange (ETDEWEB)

Majidi, M.R. [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, 29th Bahman Bolvard, Tabriz 51664 (Iran, Islamic Republic of)], E-mail: sr.majidi@gmail.com; Asadpour-Zeynali, K.; Hafezi, B. [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, 29th Bahman Bolvard, Tabriz 51664 (Iran, Islamic Republic of)

2009-01-01

The reaction and nucleation mechanism of copper electrodeposition on disposable pencil graphite electrode (PGE) in acidic sulphate solution were investigated using cyclic voltammetry (CV) and chronoamperometry (CA) techniques, respectively. Electrochemical experiments were followed by morphological studies with scanning electron microscopy (SEM). The effect of some experimental parameters, namely copper concentration, pH, scan rate, background electrolyte, deposition potential, and conditioning surface of the electrode were described. At the surface of PGE, Cu{sup 2+} ions were reduced at -250 mV vs. SCE. It was found that electrodeposition of copper is affected by rough surface of PGE. The nucleation mechanisms were examined by fitting the experimental CA data into Scharifker-Hills nucleation models. The nuclei population densities were also determined by means of two common fitting models developed for three-dimensional nucleation and growth (Scharifker-Mostany and Mirkin-Nilov-Herrman-Tarallo). It was found that deposition potential and background electrolyte affect the distribution of the deposited copper. The morphology of the deposited copper is affected by background electrolyte.

Technetium electrodeposition from aqueous formate solutions: electrolysis kinetics and material balance study

International Nuclear Information System (INIS)

Maslennikov, A.; Peretroukhine, V.

1998-01-01

The kinetics of the Tc electrodeposition and the material balance of potentiostatic electrolysis of formate buffer solutions (pH = 1.79-8.5) containing 5*10 -4 - 1*10 -2 M Tc(VII) at graphite cathode has been studied. The deposition of Tc from the solution was found to become possible at E x *y H 2 O (x ≤ 2, 1.5 cath. ) towards more negative values and the augmentation of the electrolyte surface/volume ratio (S/V) were found to increase the yield of the electrolysis and the rate of the electrodeposition process. A maximum technetium recovery of 92-95% has been observed in the electrolysis of neutral HCOONa solutions (pH = 6.0-7.5, μ = 1.0) containing up to 5*10 -1 M Tc(VII) at potentials of the graphite cathode E 2 . A starting Tc concentration in the solution of [Tc(VII)] > 5 *10 -1 M and the presence of more than 0.05 M NO 3 - in the electrolyte were found to suppress the recovery of technetium from the solution. (orig.)

Composition controlled preparation of Cu–Zn–Sn precursor films for Cu{sub 2}ZnSnS{sub 4} solar cells using pulsed electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Dang, Wenping; Ren, Xiaodong; Zi, Wei; Jia, Lujian [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Liu, Shengzhong, E-mail: szliu@dicp.ac.cn [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Dalian Institute of Chemical Physics, Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian, 116023 (China)

2015-11-25

A pulsed electrodeposition technique is developed to prepare Cu–Zn–Sn (CZT) precursor films for the Cu{sub 2}ZnSnS{sub 4} (CZTS) solar cells. The CZT precursor films are co-deposited on Mo-coated substrate using a cyanide-free electrolyte containing Zn (II) and Sn (II) salts. During the deposition, CuSO{sub 4} solution is supplied at controlled rate using a peristaltic pump to effectively regulate Cu{sup 2+} concentration. In addition, C{sub 6}H{sub 5}Na{sub 3}O{sub 7} is used as a coordination ligand to further balance activities of the Cu{sup 2+}, Sn{sup 2+} and Zn{sup 2+}. The CZTS films are then prepared using a sulfurization process to convert the electrodeposited CZT precursors at 580 °C in a sulphur atmosphere. The annealed thin films are characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), EDAX and X-ray photoelectron spectroscopy (XPS) techniques for their structural, morphological, compositional and chemical properties. It is found that the addition rate of Cu (II) has significant effects on the properties of the CZTS thin films. The CZTS film prepared using the optimized copper addition rate (0.15 ml/min) shows pure kesterite phase, Cu-poor and Zn-rich composition, compact morphology and good band gap ∼1.45 eV. Solar cells using the structure glass/Mo/CZTS/CdS/i-ZnO/ZnO:Al achieves a respectable external quantum efficiency and solar cell efficiency. - Highlights: • Developed a composition controlled pulsed electrodeposition for CZTS solar cells. • Electrochemistry and CZT composition regulated by measured Cu supply rate. • Complex chemistry used to regulate ion activities and electrodeposition. • Achieved a respectable CZTS solar cell quantum efficiency.

Electrocatalytic oxidation of some anti-inflammatory drugs on a nickel hydroxide-modified nickel electrode

Energy Technology Data Exchange (ETDEWEB)

Hajjizadeh, M. [Department of Chemistry, Faculty of Science, K. N. Toosi University of Technology, P.O. Box 16315-1618, Tehran (Iran, Islamic Republic of); Jabbari, A. [Department of Chemistry, Faculty of Science, K. N. Toosi University of Technology, P.O. Box 16315-1618, Tehran (Iran, Islamic Republic of)], E-mail: jabbari@kntu.ac.ir; Heli, H.; Moosavi-Movahedi, A.A. [Institute of Biochemistry and Biophysics, University of Tehran, Tehran (Iran, Islamic Republic of); Haghgoo, S. [Center of Quality Control of Drug, Tehran (Iran, Islamic Republic of)

2007-12-31

The electrocatalytic oxidation of several anti-inflammatory drugs (mefenamic acid, diclofenac and indomethacin) was investigated on a nickel hydroxide-modified nickel (NHMN) electrode in alkaline solution. This oxidation process and its kinetics were studied using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy techniques. Voltammetric studies indicated that in the presence of drugs, the anodic peak current of low-valence nickel species increases, followed by a decrease in the corresponding cathodic current. This pattern indicates that drugs were oxidized on the redox mediator immobilized on the electrode surface via an electrocatalytic mechanism. A mechanism based on the electrochemical generation of Ni(III) active sites and their subsequent consumption by drugs was also investigated. The corresponding rate law under the control of charge transfer was developed and kinetic parameters were derived. In this context, the charge-transfer resistance accessible both theoretically and through impedancemetry was used as a criterion. The rate constants of the catalytic oxidation of drugs and the electron-transfer coefficients are reported. A sensitive, simple and time-saving amperometric procedure was developed for the analysis of these drugs in bulk form and for the direct assay of tablets, using the NHMN electrode.

Electrocatalytic oxidation of some anti-inflammatory drugs on a nickel hydroxide-modified nickel electrode

International Nuclear Information System (INIS)

Hajjizadeh, M.; Jabbari, A.; Heli, H.; Moosavi-Movahedi, A.A.; Haghgoo, S.

2007-01-01

The electrocatalytic oxidation of several anti-inflammatory drugs (mefenamic acid, diclofenac and indomethacin) was investigated on a nickel hydroxide-modified nickel (NHMN) electrode in alkaline solution. This oxidation process and its kinetics were studied using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy techniques. Voltammetric studies indicated that in the presence of drugs, the anodic peak current of low-valence nickel species increases, followed by a decrease in the corresponding cathodic current. This pattern indicates that drugs were oxidized on the redox mediator immobilized on the electrode surface via an electrocatalytic mechanism. A mechanism based on the electrochemical generation of Ni(III) active sites and their subsequent consumption by drugs was also investigated. The corresponding rate law under the control of charge transfer was developed and kinetic parameters were derived. In this context, the charge-transfer resistance accessible both theoretically and through impedancemetry was used as a criterion. The rate constants of the catalytic oxidation of drugs and the electron-transfer coefficients are reported. A sensitive, simple and time-saving amperometric procedure was developed for the analysis of these drugs in bulk form and for the direct assay of tablets, using the NHMN electrode

Electrochemical and CMT measurements of the anomalous dissolution of nickel in solutions containing oxygen

DEFF Research Database (Denmark)

Bech-Nielsen, Gregers; de Fontenay, Frank; Poulsen, Henning

1997-01-01

In addition to single nickel crystals also nickel samples produced by dc and pr (pulse-reversal) plating were examined. As previously reported the true rate of dissolution of nickel in solutions containing oxygen was found to be as much as three times the electrochemical rate at the corrosion...... potential. When passivation was approached (spontaneously or by anodic polarization) the true rate of dissolution approached the rate of anodic reaction. During cathodic polarization there was still a significant rate of dissolution. The true rate of dissolution was determined by CMT measurements (Corrosion...

Density control of electrodeposited Ni nanoparticles/nanowires inside porous anodic alumina templates by an exponential anodization voltage decrease.

Science.gov (United States)

Marquardt, B; Eude, L; Gowtham, M; Cho, G; Jeong, H J; Châtelet, M; Cojocaru, C S; Kim, B S; Pribat, D

2008-10-08

Porous alumina templates have been fabricated by applying an exponential voltage decrease at the end of the anodization process. The time constant η of the exponential voltage function has been used to control the average thickness and the thickness distribution of the barrier layer at the bottom of the pores of the alumina structure. Depending on the η value, the thickness distribution of the barrier layer can be made very uniform or highly scattered, which allows us to subsequently fine tune the electrodeposition yield of nickel nanoparticles/nanowires at low voltage. As an illustration, the pore filling percentage with Ni has been varied, in a totally reproducible manner, between ∼3 and 100%. Combined with the ability to vary the pore diameter and repetition step over ∼2 orders of magnitude (by varying the anodization voltage and electrolyte type), the control of the pore filling percentage with metal particles/nanowires could bring novel approaches for the organization of nano-objects.

Removing nickel from nickel-coated carbon fibers

Science.gov (United States)

Hardianto, A.; Hertleer, C.; De Mey, G.; Van Langenhove, L.

2017-10-01

Conductive fibers/yarns are one of the most important materials for smart textiles because of their electrically conductive functionality combined with flexibility and light weight. They can be applied in many fields such as the medical sector, electronics, sensors and even as thermoelectric generators. Temperature sensors, for example, can be made using the thermocouple or thermopile principle which usually uses two different metal wires that can produce a temperature-dependent voltage. However, if metal wires are inserted into a textile structure, they will decrease the flexibility properties of the textile product. Nickel-coated Carbon Fiber (NiCF), a conductive textile yarn, has a potential use as a textile-based thermopile if we can create an alternating region of carbon and nickel along the fiber which in turn it can be used for substituting the metallic thermopile. The idea was to remove nickel from NiCF in order to obtain a yarn that contains alternating zones of carbon and nickel. Due to no literature reporting on how to remove nickel from NiCF, in this paper we investigated some chemicals to remove nickel from NiCF.

Behavioral interventions to reduce nickel exposure in a nickel processing plant.

Science.gov (United States)

Rumchev, Krassi; Brown, Helen; Wheeler, Amanda; Pereira, Gavin; Spickett, Jeff

2017-10-01

Nickel is a widely-used material in many industries. Although there is enough evidence that occupational exposure to nickel may cause respiratory illnesses, allergies, and even cancer, it is not possible to stop the use of nickel in occupational settings. Nickel exposure, however, can be controlled and reduced significantly in workplaces. The main objective of this study was to assess if educational intervention of hygiene behavior could reduce nickel exposure among Indonesian nickel smelter workers. Participants were randomly assigned to three intervention groups (n = 99). Group one (n = 35) received only an educational booklet about nickel, related potential health effects and preventive measures, group two (n = 35) attended a presentation in addition to the booklet, and group three (n = 29) received personal feedback on their biomarker results in addition to the booklet and presentations. Pre- and post-intervention air sampling was conducted to measure concentrations of dust and nickel in air along with worker's blood and urine nickel concentrations. The study did not measure significant differences in particles and nickel concentrations in the air between pre- and post-interventions. However, we achieved significant reductions in the post intervention urine and blood nickel concentrations which can be attributed to changes in personal hygiene behavior. The median urinary nickel concentration in the pre-intervention period for group one was 52.3 µg/L, for group two 57.4 µg/L, and group three 43.2 µg/L which were significantly higher (pnickel with significantly (p nickel levels of 0.1 µg/L for all groups. The study showed that educational interventions can significantly reduce personal exposure levels to nickel among Indonesian nickel smelter workers.

Electrodeposited cadmium selenide films for solar cells; Electrodeposition de couches minces de CdSe: Application a la conversion photovoltaique

Energy Technology Data Exchange (ETDEWEB)

Bnamar, E.; Rami, M.; Fahoume, M.; Chraibi, F.; Ennaoui, A. [Universite Mohammed 5, Rabat (Morocco). Faculte des Sciences; Fahoume, M. [Universite Ibn Tofail, Faculte des Sciences, Kenitra (Morocco)

1998-01-01

Solar cells based on II-IV semiconductors are among the leading candidates for low-cost photovoltaic conversion of solar energy due to their high absorption coefficients and therefore the low materials consumption for their production. The synthesis of polycrystalline Cd Se thin films by cathodic electrodeposition on conducting substrates is described in this paper. Electrodeposition involves potentiostatic reduction from an acid aqueous bath. The influence of bath temperature and deposition potential on the crystallinity is discussed. For optimized deposition parameters, the XRD patterns reveal cubic and hexagonal Cd Se. Electron probe microanalysis shows an excess of Se in the samples. Photoelectrochemical studies of the films in aqueous polysulfide allowed us to determine the photovoltaic properties e.g.: semiconducting type, short-circuit current, open circuit voltage and fill factor. (authors) 5 refs.

Improved corrosion behavior of nanocrystalline zinc produced by pulse-current electrodeposition

International Nuclear Information System (INIS)

Youssef, Kh.M.S.; Koch, C.C.; Fedkiw, P.S.

2004-01-01

Pulse electrodeposition was used to produce nanocrystalline (nc) zinc from zinc chloride electrolyte with polyacrylamide and thiourea as additives. Field emission scanning electron microscopy (FESEM) was used to study the grain size and surface morphology of the deposits and X-ray diffraction was used to examine their preferred orientation. Corrosion behavior of the electrodeposited nc zinc in comparison with electrogalvanized (EG) steel in de-aerated 0.5 N NaOH solution was studied using potentiodynamic polarization and impedance measurements. A scanning electron microscope (SEM) was used to characterize the surface morphology of the EG steel before corrosion testing. Surface morphologies of nc zinc deposits and EG steel were also studied after potentiondynamic polarization by SEM. Nanocrystalline zinc (56 nm) with random orientation was produced. The estimated corrosion rate of nc zinc was found to be about 60% lower than that of EG steel, 90 and 229 μA/cm 2 , respectively. The surface morphology of corroded nc zinc was characterized by discrete etch pits, however, uniform corrosion was obtained after potentiodynamic polarization of EG steel. The passive film formed on the nc zinc surface seems to be a dominating factor for the corrosion behavior observed

Electrodeposition of Zn-Co and Zn-Co-Fe alloys from acidic chloride electrolytes

NARCIS (Netherlands)

Lodhi, Z.F.; Mol, J.M.C.; Hovestad, A.; Terryn, H.; Wit, J.H.W. de

2007-01-01

The electrodeposition operating conditions for Zn-Co and Zn-Co-Fe alloys from chloride baths were studied. The electrodeposition was performed on a high strength steel substrate, under galvanostatic conditions, for a range of current densities at varying Co2+ and Fe2+ bath concentrations and at

Formation mechanism of PbTe dendritic nanostructures grown by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Bae, Sangwoo; Kim, Hyunghoon; Lee, Ho Seong, E-mail: hs.lee@knu.ac.kr

2017-02-01

The formation mechanism of PbTe dendritic nanostructures grown at room temperature by electrodeposition in nitric acid electrolytes containing Pb and Te was investigated. Scanning electron microscopy and transmission electron microscopy analyses indicated that the PbTe dendritic nanostructures were composed of triangular-shaped units surrounded by {111} and {110} planes. Because of the interfacial energy anisotropy of the {111} and {110} planes and the difference in the current density gradient, the growth rate in the vertical direction of the (111) basal plane was slower than that in the direction of the tip of the triangular shape, leading to growth in the tip direction. In contrast to the general growth direction of fcc dendrites, namely <100>, the tip direction of the {111} basal plane for our samples was <112>, and the PbTe dendritic nanostructures grew in the tip direction. The angles formed by the main trunk and first branches were regular and approximately 60°, and those between the first and second branches were also approximately 60°. Finally, the nanostructures grew in single-crystalline dendritic form. - Highlights: • PbTe dendrite nanostructures were grown by electrodeposition. • PbTe dendritic nanostructures were composed of triangular-shaped units. • The formation mechanism of PbTe dendrite nanostructures was characterized.

Super Nonlinear Electrodeposition-Diffusion-Controlled Thin-Film Selector.

Science.gov (United States)

Ji, Xinglong; Song, Li; He, Wei; Huang, Kejie; Yan, Zhiyuan; Zhong, Shuai; Zhang, Yishu; Zhao, Rong

2018-03-28

Selector elements with high nonlinearity are an indispensable part in constructing high density, large-scale, 3D stackable emerging nonvolatile memory and neuromorphic network. Although significant efforts have been devoted to developing novel thin-film selectors, it remains a great challenge in achieving good switching performance in the selectors to satisfy the stringent electrical criteria of diverse memory elements. In this work, we utilized high-defect-density chalcogenide glass (Ge 2 Sb 2 Te 5 ) in conjunction with high mobility Ag element (Ag-GST) to achieve a super nonlinear selective switching. A novel electrodeposition-diffusion dynamic selector based on Ag-GST exhibits superior selecting performance including excellent nonlinearity (<5 mV/dev), ultra-low leakage (<10 fA), and bidirectional operation. With the solid microstructure evidence and dynamic analyses, we attributed the selective switching to the competition between the electrodeposition and diffusion of Ag atoms in the glassy GST matrix under electric field. A switching model is proposed, and the in-depth understanding of the selective switching mechanism offers an insight of switching dynamics for the electrodeposition-diffusion-controlled thin-film selector. This work opens a new direction of selector designs by combining high mobility elements and high-defect-density chalcogenide glasses, which can be extended to other materials with similar properties.

Physical and electrochemical properties of ZnO films fabricated from highly cathodic electrodeposition potentials

Science.gov (United States)

Ismail, Abdul Hadi; Abdullah, Abdul Halim; Sulaiman, Yusran

2017-03-01

The physical and electrochemical properties of zinc oxide (ZnO) film electrode that were prepared electrochemically were studied. ZnO was electrodeposited on ITO glass substrate by applying three different highly cathodic potentials (-1.3 V, -1.5 V, -1.7 V) in a solution containing 70 mM of Zn(NO3)2.xH2O and 0.1 M KCl with bath temperatures of 70 °C and 80 °C. The presence of ZnO was asserted from XRD analysis where the corresponding peaks in the spectra were assigned. SEM images revealed the plate-like hexagonal morphology of ZnO which is in agreement with the XRD analysis. The areal capacitance of the ZnO was observed to increase when the applied electrodeposition potential is increased from -1.3 V to -1.5 V. However, the areal capacitance is found to decrease when the applied electrodeposition potential is further increased to -1.7 V. The resistance of charge transfer (Rct) of the ZnO decreased when the applied electrodeposition potential varies from -1.3 V to -1.7 V due to the decreased particle size of ZnO when more cathodic electrodeposition potential is applied.

Surface Morphology Study of Nanostructured Lead-Free Solder Alloy Sn-Ag-Cu Developed by Electrodeposition: Effect of Current Density Investigation

Directory of Open Access Journals (Sweden)

Sakinah Mohd Yusof

2013-10-01

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Nanostructured lead-free solder Sn-Ag-Cu (SAC was developed by electrodeposition method at room temperature. Electrolite bath which comprised of the predetermined quantity of tin methane sulfonate, copper sulfate and silver sulfate were added sequentially to MSA solution. The methane sulphonic acid (MSA based ternary Sn-Ag-Cu bath was developed by using tin methane sulfonate as a source of Sn ions while the Cu+ and Ag+ ions were obtained from their respective sulfate salts. The rate of the electrodeposition was controlled by variation of current density. The addition of the buffer, comprising of sodium and ammonium acetate helped in raising the pH solution. During the experimental procedure, the pH of solution, composition of the electrolite bath, and the electrodeposition time were kept constant. The electrodeposited rate, deposit composition and microstructure were investigated as the effect of current density. The electrodeposited solder alloy was characterized for their morphology using Field Emission Scanning Electron Microscope (FESEM. In conclusion, vary of current density will play significant role in the surface morphology of nanostructured lead-free solder SAC developed. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New

Electrodeposition synthesis and electrochemical properties of nanostructured γ-MnO 2 films

Science.gov (United States)

Chou, Shulei; Cheng, Fangyi; Chen, Jun

The thin films of carambola-like γ-MnO 2 nanoflakes with about 20 nm in thickness and at least 200 nm in width were prepared on nickel sheets by combination of potentiostatic and cyclic voltammetric electrodeposition techniques. The as-prepared MnO 2 nanomaterials, which were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were used as the active material of the positive electrode for primary alkaline Zn/MnO 2 batteries and electrochemical supercapacitors. Electrochemical measurements showed that the MnO 2 nanoflake films displayed high potential plateau (around 1.0 V versus Zn) in primary Zn/MnO 2 batteries at the discharge current density of 500 mA g -1 and high specific capacitance of 240 F g -1 at the current density of 1 mA cm -2. This indicated the potential application of carambola-like γ-MnO 2 nanoflakes in high-power batteries and electrochemical supercapacitors. The growth process for the one- and three-dimensional nanostructured MnO 2 was discussed on the basis of potentiostatic and cyclic voltammetric techniques. The present synthesis method can be extended to the preparation of other nanostructured metal-oxide films.

ELECTRODEPOSITION OF COPPER IONS ON FIXED BED ELECTRODES: KINETIC AND HYDRODYNAMIC STUDY

Directory of Open Access Journals (Sweden)

L.A.M. Ruotolo

2002-03-01

Full Text Available The kinetic and hydrodynamic behaviour of a fixed-bed electrochemical reactor was studied in terms of current efficiency (CE and energy efficiency (EE. In the kinetic experiments the effects of fixed bed thickness (L, current density (i and initial concentration of copper (C0 were studied. In the hydrodynamic experiments the permeability (k of the electrode and the coefficient for inertial forces (c were also studied as functions of the applied current density. At low current densities and bed thicknesses greater than 1.0 cm, negative CE and EE were observed as a consequence of the dissolution of the porous matrix. At high current densities low CE and EE were observed and a powdery deposit was formed on the surface of the particles. From the results of the kinetic study bed thickness and the range of current densities employed in the hydrodynamic experiments were chosen. In these experiments the electrodeposition process continued until the whole electrode had been clogged and no more electrolyte could pass through it. The relationship between pressure drop and flow rate was well described by the Forchheimer equation. It was observed that the reduction in porosity due to copper electrodeposition causes the flow rate to decrease because of the decrease in electrode permeability, but it had no influence on current efficiency.

Nickel hydrogen/nickel cadmium battery trade studies

Science.gov (United States)

Stadnick, S. J.

1983-01-01

Nickel Hydrogen cell and battery technology has matured to the point where a real choice exists between Nickel Hydrogen and Nickel Cadmium batteries for each new spacecraft application. During the past few years, a number of spacecraft programs have been evaluated at Hughes with respect to this choice, with the results being split about fifty-fifty. The following paragraphs contain criteria which were used in making the battery selection.

Near boundary acoustic streaming in Ni-Fe alloy electrodeposition control

DEFF Research Database (Denmark)

Pocwiardowski, Pawel; Lasota, H.; Ravn, Christian

2005-01-01

Alloy electrodeposition is strongly influenced by diffusion layer phenomena affecting the ion concentration distribution in a different way for each component. This paper presents the method of acoustic agitation leading to controlled uniform electrodeposition of alloys. The method consists...... in generating acoustic flow perpendicular to the surface in the field of an acoustic standing wave parallel to the plated substrate - so called modified Rayleigh streaming. The result showed that the near boundary streaming offers controlled mass transportation in the micrometer thick layer close to the cathode...

Electrodeposition of milligram amounts of uranium on electropolished stainless steel disks

International Nuclear Information System (INIS)

Aggarwal, S.K.; Shah, P.M.; Duggal, R.K.; Jain, H.C.

1991-01-01

Investigations have been carried out for the electrodeposition of milligram amounts of uranium on electropolished stainless steel disks with an objective of preparing good quality sources for α-spectrometric studies on uranium. The parameters studied include the vatiation of electrodeposition yield as a function of voltage, time, distance between the cathode and anode, and the volume of 0.2M ammonium oxalate solution. The conditions selected for preparing good quality sources with nearly 100% yield were: electrodeposition voltage 25 V, time of deposition 15 min, volume of 0.2M ammonium oxalate solution in the cell 4 ml and a distance of 2 cm between the cathode and anode. The sources prepared using this method have been used successfully for the α-spectrometric determination of 234 U/ 238 U ratios in uranium samples. (author) 6 refs.; 4 figs

Etude des mecanismes de formation des microstructures lors du brasage isotherme de superalliages a base de nickel

Science.gov (United States)

Ruiz-Vargas, Jose

This thesis reports theoretical and experimental investigations carried out to understand the mechanisms of microstructure formation during isothermal brazing, produced by brazing Inconel 625 and MC2 nickel-based superalloys with filler metal BNi-2. Firstly, studies were made on pure Ni to interpret microstructure's formation with simplified alloy chemistry. Microstructure formation have been studied when varying time at constant temperature (isothermal kinetics), but also when varying temperature for constant hold time (isochronal kinetics). The chemical composition and crystallography of the present phases have been identified, with the following results : (i) the fraction of dissolved base metal has been found proportional to the initial thickness of the brazing alloy, so that the composition of the liquid remains homogeneous with a precise initial equilibrium composition during the whole brazing process, (ii) the melting of the joint occurs in two steps : at lower temperature, it involves only partially melting, and boron diffusion in pure Ni leads to the precipitation of fine Ni3B borides at the interface ; in a second stage, at higher temperature, melting is complete and thermodynamic equilibrium requires significant dissolution of nickel, which also involves the dissolution of part of borides already formed. Secondly, nickel plating technique was used on Inconel 625 nickel-based superalloy. A thin layer of Ni with varying thickness, has been electrodeposited to observe the gradual dissolution of Inconel and microstructural features formation due to the presence of superalloy alloying elements. It has been observed that the nickel coating does not prevent precipitation in the base metal as boron diffuse rapidly through the coating width. In the intermediate nickel plating width, fragile precipitates of nickel borides have been observed, because the contribution of Inconel alloying elements to the melt was very limited. In absence of nickel plating on the

NICKEL PLATING PROCESS

Science.gov (United States)

Hoover, T.B.; Zava, T.E.

1959-05-12

A simplified process is presented for plating nickel by the vapor decomposition of nickel carbonyl. In a preferred form of the invention a solid surface is nickel plated by subjecting the surface to contact with a mixture containing by volume approximately 20% nickel carbonyl vapor, 2% hydrogen sulfide and .l% water vapor or 1% oxygen and the remainder carbon dioxide at room temperature until the desired thickness of nickel is obtained. The advantage of this composition over others is that the normally explosive nickel carbonyl is greatly stabilized.

Electrodeposited ultrafine TaOx/CB catalysts for PEFC cathode application: Their oxygen reduction reaction kinetics

KAUST Repository

Seo, Jeongsuk

2014-12-01

Ultrafine TaOx nanoparticles were electrodeposited on carbon black (CB) powder in a nonaqueous Ta complex solution at room temperature, and the resultant TaOx/CB catalysts were assessed as oxygen reduction reaction (ORR) electrocatalysts for polymer electrolyte fuel cell (PEFC) cathodes. The Ta electrodeposition process was scaled up using a newly designed working electrode containing a CB dense layer, without introducing any binder such as the ionomer Nafion in the electrode for electrodeposition. The electrodeposited TaOx/CB powders were removed from the deposition electrode and subsequent H2 treatment at varying temperatures between 523 and 1073 K was attempted to increase the ORR performance. The TaOx/CB samples were characterized by SEM, STEM, XPS, and EELS measurements. XPS and EELS results indicated the reduced nature of the Ta species caused by the high-temperature treatment in H2, while STEM images clearly revealed that the TaOx particles aggregated as the treatment temperature increased. When the TaOx/CB catalyst, which was treated at 873 K for 2 h, was deposited on a glassy carbon substrate with Nafion ionomer, it resulted in the highest activity among the samples investigated, giving an onset potential of 0.95 VRHE at -2 μA cm-2 in a 0.1 M H2SO4 solution. Moreover, the long-term stability test with 10,000 cycles of the voltammetry only led to a 6% loss in the ORR currents, demonstrating the high stability of the TaOx/CB catalysts. Kinetic analysis by R(R)DE indicated that the four-electron transfer pathway in the ORR process was dominant for this TaOx/CB catalyst, and Tafel plots showed a slope corresponding to a one-electron reaction for the rate-determining step.

Electrodeposited ultrafine TaOx/CB catalysts for PEFC cathode application: Their oxygen reduction reaction kinetics

KAUST Repository

Seo, Jeongsuk; Anjum, Dalaver H.; Takanabe, Kazuhiro; Kubota, Jun; Domen, Kazunari

2014-01-01

Ultrafine TaOx nanoparticles were electrodeposited on carbon black (CB) powder in a nonaqueous Ta complex solution at room temperature, and the resultant TaOx/CB catalysts were assessed as oxygen reduction reaction (ORR) electrocatalysts for polymer electrolyte fuel cell (PEFC) cathodes. The Ta electrodeposition process was scaled up using a newly designed working electrode containing a CB dense layer, without introducing any binder such as the ionomer Nafion in the electrode for electrodeposition. The electrodeposited TaOx/CB powders were removed from the deposition electrode and subsequent H2 treatment at varying temperatures between 523 and 1073 K was attempted to increase the ORR performance. The TaOx/CB samples were characterized by SEM, STEM, XPS, and EELS measurements. XPS and EELS results indicated the reduced nature of the Ta species caused by the high-temperature treatment in H2, while STEM images clearly revealed that the TaOx particles aggregated as the treatment temperature increased. When the TaOx/CB catalyst, which was treated at 873 K for 2 h, was deposited on a glassy carbon substrate with Nafion ionomer, it resulted in the highest activity among the samples investigated, giving an onset potential of 0.95 VRHE at -2 μA cm-2 in a 0.1 M H2SO4 solution. Moreover, the long-term stability test with 10,000 cycles of the voltammetry only led to a 6% loss in the ORR currents, demonstrating the high stability of the TaOx/CB catalysts. Kinetic analysis by R(R)DE indicated that the four-electron transfer pathway in the ORR process was dominant for this TaOx/CB catalyst, and Tafel plots showed a slope corresponding to a one-electron reaction for the rate-determining step.

Stable lithium electrodeposition in salt-reinforced electrolytes

KAUST Repository

Lu, Yingying; Tu, Zhengyuan; Shu, Jonathan; Archer, Lynden A.

2015-01-01

© 2015 Elsevier B.V. Development of high-energy lithium-based batteries that are safe remains a challenge due to the non-uniform lithium electrodeposition during repeated charge and discharge cycles. We report on the effectiveness of lithium bromide

Atomistic minimal model for estimating profile of electrodeposited nanopatterns

Science.gov (United States)

Asgharpour Hassankiadeh, Somayeh; Sadeghi, Ali

2018-06-01

We develop a computationally efficient and methodologically simple approach to realize molecular dynamics simulations of electrodeposition. Our minimal model takes into account the nontrivial electric field due a sharp electrode tip to perform simulations of the controllable coating of a thin layer on a surface with an atomic precision. On the atomic scale a highly site-selective electrodeposition of ions and charged particles by means of the sharp tip of a scanning probe microscope is possible. A better understanding of the microscopic process, obtained mainly from atomistic simulations, helps us to enhance the quality of this nanopatterning technique and to make it applicable in fabrication of nanowires and nanocontacts. In the limit of screened inter-particle interactions, it is feasible to run very fast simulations of the electrodeposition process within the framework of the proposed model and thus to investigate how the shape of the overlayer depends on the tip-sample geometry and dielectric properties, electrolyte viscosity, etc. Our calculation results reveal that the sharpness of the profile of a nano-scale deposited overlayer is dictated by the normal-to-sample surface component of the electric field underneath the tip.

High-performance flexible electrode based on electrodeposition of polypyrrole/MnO2 on carbon cloth for supercapacitors

Science.gov (United States)

Fan, Xingye; Wang, Xiaolei; Li, Ge; Yu, Aiping; Chen, Zhongwei

2016-09-01

A highly flexible electrodes based on electrodeposited MnO2 and polypyrrole composite on carbon cloth is designed and developed by a facile in-situ electrodeposition technique. Such flexible composite electrodes with multiply layered structure possess a high specific capacitance of 325 F g-1 at a current density of 0.2 A g-1, and an excellent rate capability with a capacitance retention of 70% at a high current density of 5.0 A g-1. The superior electrochemical performance is mainly due to the unique electrode with improved ion- and electron-transportation pathways as well as the efficient utilization of active materials and electrode robustness. The excellent electrochemical performance and the low cost property endow this flexible nanocomposite electrode with great promise in applications of flexible supercapacitors.

Carbon deposition on nickel ferrites and nickel-magnetite surfaces

International Nuclear Information System (INIS)

Allen, G.C.; Jutson, J.A.

1988-06-01

Carbon deposition on Commercial Advanced Gas-Cooled Reactor (CAGR) fuel cladding and heat exchanger surfaces lowers heat transfer efficiency and increases fuel pin temperatures. Several types of deposit have been identified including both thin dense layers and also low density columnar deposits with filamentary or convoluted laminar structure. The low-density types are often associated with particles containing iron, nickel or manganese. To identify the role of nickel in the deposition process surfaces composed of nickel-iron spinels or metallic nickel/magnetite mixtures have been exposed to γ radiation in a gas environment simulating that in the reactor. Examination of these surfaces by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) have shown that while metallic nickel (Ni(O)) catalyses the formation of filamentary low density carbon deposits, the presence of divalent nickel (Ni(II)) sites in spinel type oxides is associated only with dense deposits. (author)

Electrodeposition and characterization of Fe–Mo alloys as cathodes for hydrogen evolution in the process of chlorate

Directory of Open Access Journals (Sweden)

B. N. GRGUR

2005-06-01

Full Text Available Fe–Mo alloys were electrodeposited from a pyrophosphate bath using a single diode rectified AC current. Their composition and morphology were investigated by SEM, optical microscopy and EDS, in order to determine the influence of the deposition conditions on the morphology and composition of these alloys. It was shown that the electrodeposition parameters, such as: chemical bath composition and current density, influenced both the composition of the Fe–Mo alloys and the current efficiency for their deposition, while the micro and macro-morphology did not change significantly with changing conditions of alloy electrodeposition. It was found that the electrodeposited Fe–Mo alloys possessed a 0.15 V to 0.30 V lower overvoltage than mild steel for hydrogen evolution in an electrolyte commonly used in commercial chlorate production, depending on the alloy composition, i.e., the conditions of alloy electrodeposition.

Controllable wettability and morphology of electrodeposited surfaces on zinc substrates

Energy Technology Data Exchange (ETDEWEB)

Zhang, Binyan; Lu, Shixiang, E-mail: shixianglu@bit.edu.cn; Xu, Wenguo, E-mail: wenguoxu60@bit.edu.cn; Cheng, Yuanyuan

2016-01-01

Graphical abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching, electrodeposition of ZnO coatings and annealing. Such superhydrophobic surfaces offer possibilities for chemical, biological, electronic and microfluidic applications. - Highlights: • Superhydrophobic surface was fabricated via electrodeposition of ZnO and annealing. • The ZnO hierarchical micro/nanostructures contribute to the surface superhydrophobicity. • Surface wettability and morphology can be controlled by varying process conditions. • The anti-icing properties and reversible wetting behaviors of the ZnO coatings were studied. - Abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching in hydrochloric acid solution, electrodeposition of ZnO coatings and subsequent thermal annealing. The optimal coatings were electrodeposited at −1.25 V for 900 s on the etched zinc substrates and then annealed at 200 °C for 60 min, which could achieve a maximum water contact angle of 170 ± 2° and an ultra-low sliding angle of approximately 0°. By conducting SEM and water CA analysis, we found that the morphology and wettability of prepared samples were controllable by the fabrication process. Interestingly, even without any additional modification, the samples prepared under different electrodeposition conditions (including Zn(CH{sub 3}COO){sub 2} concentration from 5 mM to 40 mM and deposition time from 300 s to 1500 s) exhibited superhydrophobic character. The influences of the Zn(CH{sub 3}COO){sub 2} concentration, deposition time, annealing temperature and annealing time on the wetting behaviors were also discussed in detail. Such superhydrophobic surfaces possess long-term stability, and good corrosion resistance as well as self-cleaning ability. In addition, the anti-icing properties of the ZnO films were investigated. These surfaces could be rapidly and

Controllable wettability and morphology of electrodeposited surfaces on zinc substrates

International Nuclear Information System (INIS)

Zhang, Binyan; Lu, Shixiang; Xu, Wenguo; Cheng, Yuanyuan

2016-01-01

Graphical abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching, electrodeposition of ZnO coatings and annealing. Such superhydrophobic surfaces offer possibilities for chemical, biological, electronic and microfluidic applications. - Highlights: • Superhydrophobic surface was fabricated via electrodeposition of ZnO and annealing. • The ZnO hierarchical micro/nanostructures contribute to the surface superhydrophobicity. • Surface wettability and morphology can be controlled by varying process conditions. • The anti-icing properties and reversible wetting behaviors of the ZnO coatings were studied. - Abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching in hydrochloric acid solution, electrodeposition of ZnO coatings and subsequent thermal annealing. The optimal coatings were electrodeposited at −1.25 V for 900 s on the etched zinc substrates and then annealed at 200 °C for 60 min, which could achieve a maximum water contact angle of 170 ± 2° and an ultra-low sliding angle of approximately 0°. By conducting SEM and water CA analysis, we found that the morphology and wettability of prepared samples were controllable by the fabrication process. Interestingly, even without any additional modification, the samples prepared under different electrodeposition conditions (including Zn(CH_3COO)_2 concentration from 5 mM to 40 mM and deposition time from 300 s to 1500 s) exhibited superhydrophobic character. The influences of the Zn(CH_3COO)_2 concentration, deposition time, annealing temperature and annealing time on the wetting behaviors were also discussed in detail. Such superhydrophobic surfaces possess long-term stability, and good corrosion resistance as well as self-cleaning ability. In addition, the anti-icing properties of the ZnO films were investigated. These surfaces could be rapidly and reversibly switched

Vapour and electro-deposited metal films on copper: structure and reactivity

OpenAIRE

McEvoy, Thomas F.

2004-01-01

The systems studied involve deposition of metals of a larger atomic diameter on a Cu{100} single crystal surface under vacuum and determining the structures formed along with the effect on the Cu{100} substrate. Cu microelectrodes were fabricated and characterised with Indium electrodeposited on the electrode surface. The In on Cu{ 100} growth mode is compared with the growth mode of electrodeposited Indium on Cu microelectrodes. The Cu{100}/In system has been studied for the In coverage ...

The EU Nickel Directive revisited--future steps towards better protection against nickel allergy

DEFF Research Database (Denmark)

Thyssen, Jacob P; Uter, Wolfgang; McFadden, John

2011-01-01

In July 2001, the EU Nickel Directive came into full force to protect European citizens against nickel allergy and dermatitis. Prior to this intervention, Northern European governments had already begun to regulate consumer nickel exposure. According to part 2 of the EU Nickel Directive and the D......In July 2001, the EU Nickel Directive came into full force to protect European citizens against nickel allergy and dermatitis. Prior to this intervention, Northern European governments had already begun to regulate consumer nickel exposure. According to part 2 of the EU Nickel Directive...... and the Danish nickel regulation, consumer items intended to be in direct and prolonged contact with the skin were not allowed to release more than 0.5 µg nickel/cm2/week. It was considered unlikely that nickel allergy would disappear altogether as a proportion of individuals reacted below the level defined...

dK/da effects on the SCC growth rates of nickel base alloys in high-temperature water

Science.gov (United States)

Chen, Kai; Wang, Jiamei; Du, Donghai; Andresen, Peter L.; Zhang, Lefu

2018-05-01

The effect of dK/da on crack growth behavior of nickel base alloys has been studied by conducting stress corrosion cracking tests under positive and negative dK/da loading conditions on Alloys 690, 600 and X-750 in high temperature water. Results indicate that positive dK/da accelerates the SCC growth rates, and the accelerating effect increases with dK/da and the initial CGR. The FRI model was found to underestimate the dK/da effect by ∼100X, especially for strain hardening materials, and this underscores the need for improved insight and models for crack tip strain rate. The effect of crack tip strain rate and dK/dt in particular can explain the dK/da accelerating effect.

Effect of current density and pH in obtaining the Ni-Fe alloy by electrodeposition; Efeito da densidade de corrente e pH na obtencao da liga Ni-Fe por eletrodeposicao

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Jose Anderson Machado; Raulino, Anamelia de Medeiros Dantas; Raulino, Jose Leonardo Costa; Campos, Ana Regina Nascimento; Prasad, Shiva; Santana, Renato Alexandre Costa de, E-mail: jmo.anderson@gmail.com, E-mail: anameliadantas@yahoo.com.br, E-mail: leonardo.jcr@hotmail.com, E-mail: arncampos@yahoo.com.br, E-mail: prasad@deq.ufcg.edu.br, E-mail: renatoacs@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), Cuite, PB (Brazil). Lab. de Eletroquimica e Corrosao

2017-01-15

Metallic coatings can be applied for different purposes, for example to improve the mechanical, catalytic, anti corrosive properties or simply to improve the decorative appearance. In the work the Fe-Ni alloys have been obtained by electrodeposition process using a simple electrolytic bath containing the reagents, nickel sulfate, iron sulfate and sodium tartrate. A complete experimental design 2{sup 2} , associated with the response surface methodology (RSM) technique was used as optimization tool. Chemical composition, current efficiency, surface morphology and electrochemical corrosion measures were performed. It was observed that a decrease in the pH favored an increase in iron and decrease in nickel contents in the alloy. The iron content influenced the alloy morphology. The best experiment showed an average corrosion resistance 5471.5 Ω.cm² and a corrosion current density 4.814x10{sup -6} A/cm². This experiment presented a composition of 70 wt% Ni and 30 wt% Fe in the alloy and an average deposition current efficiency of 58.7%. (author)

Uniform deposition of water-soluble CdS quantum dots on TiO2 nanotube arrays by cyclic voltammetric electrodeposition: Effectively prevent aggregation and enhance visible-light photocatalytic activity

International Nuclear Information System (INIS)

Zhang, Xiaojiao; Lin, Shiwei; Liao, Jianjun; Pan, Nengqian; Li, Danhong; Cao, Xiankun; Li, Jianbao

2013-01-01

Highlights: • Water-soluble CdS QDs were deposited on the TNTAs by DC electrodeposition, CV electrodeposition, and SILAR. • The CV method could effectively prevent the aggregation and uniformly deposit CdS QDs onto the TNTAs. • The CTAB/CdS/TNTAs prepared by the CV method exhibited superior photoelectrical properties and photocatalytic activity. -- Abstract: Water-soluble CdS quantum dots (QDs) covered with cationic surfactant-cetyltrimethylammonium bromide (CTAB) were deposited on the highly ordered TiO 2 nanotube arrays (TNTAs) by various methods, such as direct current (DC) electrodeposition, cyclic voltammetric (CV) electrodeposition, and successive ionic layer adsorption reaction (SILAR). The morphology measurements show that CTAB capping could well control the QD size and the CV method could effectively prevent the nanoparticle aggregation and uniformly deposit QDs onto TNTAs. Among all the deposition methods studied, the sample prepared by the CV method possesses superior photoelectrical properties and photocatalytic activity. A maximum photoconversion efficiency of 2.81% is achieved for the CdS/TNTAs prepared by CV electrodeposition, which exhibits about 17 times enhancement over the efficiency of the sample prepared by DC electrodeposition. And the photocatalytic degradation of methyl orange under visible-light irradiation demonstrates that the rate constant of the sample prepared by the CV method is almost seven times of that of the untreated TNTAs. Moreover, the underlying mechanism for the improving properties has been discussed

Hydrodynamic voltammetric studies of the oxygen reduction at gold nanoparticles-electrodeposited gold electrodes

International Nuclear Information System (INIS)

El-Deab, Mohamed S.; Ohsaka, Takeo

2002-01-01

The electrocatalytic reduction of oxygen at Au nanoparticles-electrodeposited Au electrodes has been studied using rotating disk electrode (RDE) voltammetry in 0.5 M H 2 SO 4 . Upon analyzing and comparison of the limiting currents data obtained at various rotation speeds of this RDE with those obtained at the bulk Au electrode, an effective value of the number of electrons, n, involved in the electrochemical reduction of O 2 was estimated to be ca. 4 for the former electrode and ca. 3 for the bulk Au electrode at the same potential of -350 mV versus Ag/AgCl/KCl(sat.). This indicates the higher possibility of further reduction and decomposition of H 2 O 2 at Au nanoparticles-electrodeposited Au electrode in this acidic medium. The reductive desorption of the self-assembled monolayer of cysteine, which was formed on the Au nanoparticles-electrodeposited Au electrode, was used to monitor the change of the specific activity of the bulk Au electrode upon the electrodeposition of the Au nanoparticles

Development of silver-gas diffusion electrodes for the oxygen reduction reaction by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Salomé, Sónia; Rego, Rosa; Oliveira, M. Cristina, E-mail: mcris@utad.pt

2013-12-16

Silver-gas diffusion electrodes (Ag-GDE) were prepared by direct deposition of the catalyst onto a carbon paper support by electrodeposition. This deposition technique, under potentiostatic and galvanostatic mode, allows the production of well dispersed ultra-low Ag loading levels. The catalytic activity of the prepared materials towards the oxygen reduction reaction (ORR) was investigated in the alkaline solution and its tolerance to methanol was evaluated. Based on an Ag-ink prepared from the electrodeposit material and RDE experiments, it was concluded that the ORR occurs via a four-electron pathway on the Ag electrodeposit. The combination of reasonably high catalytic activity, efficiency, low price, facile and green synthesis makes the electrodeposited Ag-GDE attractive for the ORR in alkaline fuel cells. - Highlights: • A facile and simple way to successfully prepare catalyzed gas diffusion electrodes. • Ultra-low loadings of Ag-GDEs can be achieved. • Good tolerance to methanol and a high mass activity (3.14 mA{sub Ag} mg{sup −1}). • ORR occurs via a four-electron pathway.

Electrolytic Recovery of Nickel from Spent Electroless Nickel Bath Solution

Directory of Open Access Journals (Sweden)

R. Idhayachander

2010-01-01

Full Text Available Plating industry is one of the largest polluting small scale industries and nickel plating is among the important surface finishing process in this industry. The waste generated during this operation contains toxic nickel. Nickel removal and recovery is of great interest from spent bath for environmental and economic reasons. Spent electroless nickel solution from a reed relay switch manufacturing industry situated in Chennai was taken for electrolytic recovery of nickel. Electrolytic experiment was carried out with mild steel and gold coated mild steel as cathode and the different parameters such as current density, time, mixing and pH of the solution were varied and recovery and current efficiency was studied. It was noticed that there was an increase in current efficiency up to 5 A/dm2 and after that it declines. There is no significant improvement with mixing but with modified cathode there was some improvement. Removal of nickel from the spent electroless nickel bath was 81.81% at 5 A/dm2 and pH 4.23. Under this condition, the content of nickel was reduced to 0.94 g/L from 5.16 g/L. with 62.97% current efficiency.

Effective and Environmentally Friendly Nickel Coating on the Magnesium Alloy

Directory of Open Access Journals (Sweden)

Ivana Škugor Rončević

2016-12-01

Full Text Available The low density and good mechanical properties make magnesium and its alloys attractive construction materials in the electronics, automotive, and aerospace industry, together with application in medicine due to their biocompatibility. Magnesium AZ91D alloy is an alloy with a high content of aluminum, whose mechanical properties overshadow the low corrosion resistance caused by the composition of the alloy and the existence of two phases: α magnesium matrix and β magnesium aluminum intermetallic compound. To improve the corrosion resistance, it is necessary to find an effective protection method for the alloy surface. Knowing and predicting electrochemical processes is an essential for the design and optimization of protective coatings on magnesium and its alloys. In this work, the formations of nickel protective coatings on the magnesium AZ91D alloy surface by electrodeposition and chemical deposition, are presented. For this purpose, environmentally friendly electrolytes were used. The corrosion resistance of the protected alloy was determined in chloride medium using appropriate electrochemical techniques. Characterization of the surface was performed with highly sophisticated surface-analytical methods.

The Effects of Electroless Nickel Plating Bath Conditions on Stability of Solution and Properties of Deposit

International Nuclear Information System (INIS)

Huh, Jin; Lee, Jae Ho

2000-01-01

Electroless depositions of nickel were conducted in different bath conditions to find optimum conditions of electroless nickel plating at low operating temperature and pH. The effect of complexing reagent on stability of plating solution was investigated. Sodium citrate complexed plating solution is more stable than sodium pyrophosphate complexed solution. The effects of nickel salt concentration, reducing agent, complexing agent and inhibitor on deposition rate was investigated. The effects of pH on deposition rate and content of phosphorous in deposited nickel were also analyzed. Electroless deposited nickel become crystallized with increasing pH due to lower phosphorous content. In optimum operating bath condition, deposition rate was 7 μm/hr at 60 .deg. C and pH 10.0 without stabilizer. The rate was decreased with stabilizer concentration

Human exposure to nickel

Energy Technology Data Exchange (ETDEWEB)

Grandjean, P

1984-01-01

In order of abundance in the earth's crust, nickel ranks as the 24th element and has been detected in different media in all parts of the biosphere. Thus, humans are constantly exposed to this ubiquitous element, though in variable amounts. Occupational exposures may lead to the retention of 100 micrograms of nickel per day. Environmental nickel levels depend particularly on natural sources, pollution from nickel-manufacturing industries and airborne particles from combustion of fossil fuels. Absorption from atmospheric nickel pollution is of minor concern. Vegetables usually contain more nickel than do other food items. Certain products, such as baking powder and cocoa powder, have been found to contain excessive amounts of nickel, perhaps related to nickel leaching during the manufacturing process. Soft drinking-water and acid beverages may dissolve nickel from pipes and containers. Scattered studies indicate a highly variable dietary intake of nickel, but most averages are about 200-300 micrograms/day. In addition, skin contact to a multitude of metal objects may be of significance to the large number of individuals suffering from contact dermatitis and nickel allergy. Finally, nickel alloys are often used in nails and prostheses for orthopaedic surgery, and various sources may contaminate intravenous fluids. Thus, human nickel exposure originates from a variety of sources and is highly variable. Occupational nickel exposure is of major significance, and leaching of nickel may add to dietary intakes and to cutaneous exposures. 79 references.

Synthesis of Nickel and Nickel Hydroxide Nanopowders by Simplified Chemical Reduction

Directory of Open Access Journals (Sweden)

Jeerapan Tientong

2014-01-01

Full Text Available Nickel nanopowders were synthesized by a chemical reduction of nickel ions with hydrazine hydrate at pH ~12.5. Sonication of the solutions created a temperature of 54–65°C to activate the reduction reaction of nickel nanoparticles. The solution pH affected the composition of the resulting nanoparticles. Nickel hydroxide nanoparticles were formed from an alkaline solution (pH~10 of nickel-hydrazine complexed by dropwise titration. X-ray diffraction of the powder and the analysis of the resulting Williamson-Hall plots revealed that the particle size of the powders ranged from 12 to 14 nm. Addition of polyvinylpyrrolidone into the synthesis decreased the nickel nanoparticle size to approximately 7 nm. Dynamic light scattering and scanning electron microscopy confirmed that the particles were in the nanometer range. The structure of the synthesized nickel and nickel hydroxide nanoparticles was identified by X-ray diffraction and Fourier transform infrared spectroscopy.

Microstructure and micromechanical properties of electrodeposited Zn–Mo coatings on steel

Energy Technology Data Exchange (ETDEWEB)

Kazimierczak, Honorata, E-mail: h.kazimierczak@imim.pl [Institute of Metallurgy and Material Science, Polish Academy of Sciences, 30-059 Krakow, Reymonta 25 (Poland); Ozga, Piotr [Institute of Metallurgy and Material Science, Polish Academy of Sciences, 30-059 Krakow, Reymonta 25 (Poland); Berent, Katarzyna [Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, 30-059 Krakow, Mickiewicza Av. 30 (Poland); Kot, Marcin [Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, 30-059 Krakow, Mickiewicza Av. 30 (Poland)

2015-07-05

Highlights: • The conditions for electrodeposition of uniform and compact Zn–Mo coatings have been studied. • Zn–Mo coatings microstructure can be controlled by the molybdenum content. • Surface roughness can be controlled by the content of Mo in coatings. • The value of microhardness grows gradually with the increase of Mo content up to 3 wt.%. - Abstract: The aim of the work was to characterise the new coating material based on zinc with the addition of molybdenum, electrodeposited on steel substrate from nontoxic, citrate based electrolytes. The surface composition of deposits was ascertained by chemical analysis (WDXRF). The morphology of coatings was studied by SEM. The surface morphology and roughness of Zn–Mo coatings on steel was investigated by AFM. The microhardness and Young modulus were determined by indentation technique, whereas the coating adhesion to the substrate was examined by means of scratch test. The optimal ranges of electrodeposition parameters, enabling the preparation of good quality coatings (i.e. uniform, compact, with good adhesion to the substrate), was specified. The morphology of deposits depends significantly on the content of molybdenum and on the thickness of electrodeposited layer. The microhardness of Zn–Mo coating increases with the increase of molybdenum content up to 3 wt.% and then reaches about 3.5 GPa, which is almost five times that of the value of the microhardness of the Zn coating studied.

Electrodeposition of quaternary alloys in the presence of magnetic field

Science.gov (United States)

2010-01-01

Electrodeposition of Ni-Co-Fe-Zn alloys was done in a chloride ion solution with the presence and absence of a Permanent Parallel Magnetic Field (PPMF). The PPMF was applied parallel to the cathode surface. The deposition profile was monitored chronoamperometrically. It was found that the electrodeposition current was enhanced in the presence of PPMF (9 T) compared to without PPMF. The percentage of current enhancement (Γ%) was increased in the presence of PPMF, with results of Γ% = 11.9%, 16.7% and 18.5% at -1.1, -1.2 and -1.3 V respectively for a 2400 sec duration. In chronoamperometry, the Composition Reference Line (CRL) for Ni was around 57%, although the nobler metals (i.e. Ni, Co) showed anomalous behaviour in the presence of Zn and Fe. The anomalous behaviour of the Ni-Co-Fe-Zn electrodeposition was shown by the Energy Dispersive X-Ray (EDX) results. From Atomic Force Microscopy (AFM) measurements, it was found that the surface roughness of the Ni-Co-Fe-Zn alloy films decreased in the presence of a PPMF. PMID:20604934

Electrodeposition and Thermoelectric Properties of Cu-Se Binary Compound Films

Science.gov (United States)

Yang, Mengqian; Shen, Zhengwu; Liu, Xiaoqing; Wang, Wei

2016-03-01

Cu-Se binary compound films have been prepared by electrodeposition from solutions containing CuSO4, H2SeO3, and H2SO4 and their composition, structure, and thermoelectric performance analyzed. Moving the depositing potential negatively increased the Cu content in the film, remarkably so for relatively low Cu2+ concentration in the solution. X-ray diffraction analysis showed that the phase composition of the films varied with their Cu content. Cu-Se binary compound films electrodeposited from solutions with different concentration ratios of CuSO4 to H2SeO3 showed two different phases: α-Cu2- x Se (monoclinic) with Se content in the range of 33.3 at.% to 33.8 at.%, and β-Cu2Se (cubic) with Se content in the range of 35.3 at.% to 36.0 at.%. The highest power factor for electrodeposited Cu2- x Se film was 0.13 mW/(K2 m) with Seebeck coefficient of 56.0 μV/K.

Defect structure of electrodeposited chromium layers

International Nuclear Information System (INIS)

Marek, T.; Suevegh, K.; Vertes, A.; El-Sharif, M.; McDougall, J.; Chisolm, C.U.

2000-01-01

Positron annihilation spectroscopy was applied to study the effects of pre-treatment and composition of substrates on the quality and defect structure of electrodeposited thick chromium coatings. The results show that both parameters are important, and a scenario is proposed why the mechanically polished substrate gives more defective film than the electro polished one.

Defect structure of electrodeposited chromium layers

Energy Technology Data Exchange (ETDEWEB)

Marek, T. E-mail: marek@para.chem.elte.hu; Suevegh, K.; Vertes, A.; El-Sharif, M.; McDougall, J.; Chisolm, C.U

2000-06-01

Positron annihilation spectroscopy was applied to study the effects of pre-treatment and composition of substrates on the quality and defect structure of electrodeposited thick chromium coatings. The results show that both parameters are important, and a scenario is proposed why the mechanically polished substrate gives more defective film than the electro polished one.

Free ionic nickel accumulation and localization in the freshwater zooplankter, Daphnia magna

International Nuclear Information System (INIS)

Hall, T.M.

1982-01-01

The processes which lead to the accumulation of free ionic nickel (radioactive) from solution by Daphnia magna were studied and incorporated into a model which describes accummulation at different concentrations. Adsorption proved to be a relatively small component of nickel accummulation. The accummulation rate eventually approached zero, which represented an equilibrium between uptake and loss of nickel. However, elimination experiments did reveal a pool of relatively static nickel. The appearance and distribution of nickel within five body parts (body fluid, carapace, gut, filtering appendages, and eggs) of D. magna supported the accummulation data and added to the understanding of the pathways of nickel through the organism

Nickel and ocean warming affect scleractinian coral growth.

Science.gov (United States)

Biscéré, T; Lorrain, A; Rodolfo-Metalpa, R; Gilbert, A; Wright, A; Devissi, C; Peignon, C; Farman, R; Duvieilbourg, E; Payri, C; Houlbrèque, F

2017-07-15

The sensitivity of corals and their Symbiodinium to warming has been extensively documented; however very few studies considered that anthropogenic inputs such as metal pollution have already an impact on many fringing reefs. Thus, today, nickel releases are common in coastal ecosystems. In this study, two major reef-building species Acropora muricata and Pocillopora damicornis were exposed in situ to ambient and moderate nickel concentrations on a short-term period (1h) using benthic chamber experiments. Simultaneously, we tested in laboratory conditions the combined effects of a chronic exposure (8weeks) to moderate nickel concentrations and ocean warming on A. muricata. The in situ experiment highlighted that nickel enrichment, at ambient temperature, stimulated by 27 to 47% the calcification rates of both species but not their photosynthetic performances. In contrast, an exposure to higher nickel concentration, in combination with elevated temperature simulated in aquaria, severely depressed by 30% the growth of A. muricata. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gas Sensors Based on Electrodeposited Polymers

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Boris Lakard

2015-07-01

Full Text Available Electrochemically deposited polymers, also called “synthetic metals”, have emerged as potential candidates for chemical sensing due to their interesting and tunable chemical, electrical, and structural properties. In particular, most of these polymers (including polypyrrole, polyaniline, polythiophene and their derivatives can be used as the sensitive layer of conductimetric gas sensors because of their conducting properties. An important advantage of polymer-based gas sensors is their efficiency at room temperature. This characteristic is interesting since most of the commercially-available sensors, usually based on metal oxides, work at high temperatures (300–400 °C. Consequently, polymer-based gas sensors are playing a growing role in the improvement of public health and environment control because they can lead to gas sensors operating with rapid detection, high sensitivity, small size, and specificity in atmospheric conditions. In this review, the recent advances in electrodeposited polymer-based gas sensors are summarized and discussed. It is shown that the sensing characteristics of electrodeposited polymers can be improved by chemical functionalization, nanostructuration, or mixing with other functional materials to form composites or hybrid materials.

Fabrication of Ni-Mn Microprobe Structure with Low Internal Stress and High Hardness by Employing DC Electrodeposition

Directory of Open Access Journals (Sweden)

Kuan-Hui Cheng

2014-01-01

Full Text Available Due to its widely tunable mechanical property and incompatibility with most solders, Ni-Mn alloy can become a viable candidate in the fabrication of testing probe for microelectronic devices. In this study, the electrodeposition of Ni-Mn alloy in nickel sulphamate electrolyte with the addition of manganese sulphate was investigated under direct current (DC power source. The effects of current density and Mn2+ concentration in the electrolyte on the coating composition, cathodic efficiency, microstructure and mechanical properties were explored. The results showed that the raise of the Mn2+ concentration in the electrolyte alone did not effectively increase the Mn content in the coating but reduce the cathodic efficiency. On the other hand, increasing the current density facilitated the codeposition of the Mn and rendered the crystallite from coarse columnar grain to the refined one. Thus, both hardness and internal stress of the coating increased. The fabrication of testing probes at 1 A/dm2 was shown to satisfy the high hardness, low internal stress, reasonable fatigue life, and nonsticking requirements for this microelectronic application.

The EU Nickel Directive revisited--future steps towards better protection against nickel allergy

DEFF Research Database (Denmark)

Thyssen, Jacob P; Uter, Wolfgang; McFadden, John

2011-01-01

In July 2001, the EU Nickel Directive came into full force to protect European citizens against nickel allergy and dermatitis. Prior to this intervention, Northern European governments had already begun to regulate consumer nickel exposure. According to part 2 of the EU Nickel Directive...... by the EU Nickel Directive. Despite this, the EU Nickel Directive part 2 was expected to work as an operational limit that would sufficiently protect European consumers against nickel allergy and dermatitis. This review presents the accumulation of epidemiological studies that evaluated the possible effect...... and the Danish nickel regulation, consumer items intended to be in direct and prolonged contact with the skin were not allowed to release more than 0.5 µg nickel/cm2/week. It was considered unlikely that nickel allergy would disappear altogether as a proportion of individuals reacted below the level defined...

Depth profile analysis of electrodeposited nanoscale multilayers by Secondary Neutral Mass Spectrometry (SNMS)

International Nuclear Information System (INIS)

Katona, G.L.; Berenyi, Z.; Vad, K.; Peter, L.

2006-01-01

Complete text of publication follows. Nanoscale multilayers have been in the focus of research since the discovery of the giant magnetoresistance (GMR) effect in this family of nanostructures. The first observation of GMR on sputtered magnetic/non-magnetic multilayers was followed by the detection of the same effect in electrodeposited Co-Ni-Cu/Cu multilayers within half a decade. Electrodeposition has long been considered as an inexpensive alternative of the high-vacuum methods to produce multilayers with GMR, although the GMR effect observed for electrodeposited multilayers is usually inferior to multilayers produced by physical methods. Electrochemistry appears to be an exclusive technology to produce multilayered nanowires by using porous templates. In spite of the large number of papers about the multilayers themselves, data on the depth profile of electrodeposited multilayer samples are very scarce. It has long been known that the simultaneous electrodeposition of the iron group metals takes place in the so-called anomalous manner. The diagnostic criterion of the anomalous codeposition is that the metallic component of lower standard potential (the Co in the case of Ni/Co) can be discharged together with the more noble one (Ni) at potentials where the less noble component (Co) alone cannot be deposited onto a substrate composed of the parent metal; moreover, the less noble metal (Co) is deposited preferentially. We have investigated the composition gradient along the growth direction of electrodeposited Co/Cu and CoNiCu/Cu multilayers films using SNMS. Samples were electrodeposited using the single bath method. Commercial Cu sheets and an Cr/Cu layer evaporated onto Si (111) surface were used as substrates with high and low roughness, respectively. The depth profiles of the samples were recorded using SNMS (INA-X, Specs GmbH, Berlin) in the Direct Bombardment Mode. Depth profile analysis of electrodeposited magnetic/nonmagnetic layered structures on

Oxidation characteristics of porous-nickel prepared by powder metallurgy and cast-nickel at 1273 K in air for total oxidation time of 100 h

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Lamiaa Z. Mohamed

2017-11-01

Full Text Available The oxidation behavior of two types of inhomogeneous nickel was investigated in air at 1273 K for a total oxidation time of 100 h. The two types were porous sintered-nickel and microstructurally inhomogeneous cast-nickel. The porous-nickel samples were fabricated by compacting Ni powder followed by sintering in vacuum at 1473 K for 2 h. The oxidation kinetics of the samples was determined gravimetrically. The topography and the cross-section microstructure of each oxidized sample were observed using optical and scanning electron microscopy. X-ray diffractometry and X-ray energy dispersive analysis were used to determine the nature of the formed oxide phases. The kinetic results revealed that the porous-nickel samples had higher trend for irreproducibility. The average oxidation rate for porous- and cast-nickel samples was initially rapid, and then decreased gradually to become linear. Linear rate constants were 5.5 × 10−8 g/cm2 s and 3.4 × 10−8 g/cm2 s for the porous- and cast-nickel samples, respectively. Initially a single-porous non-adherent NiO layer was noticed on the porous- and cast-nickel samples. After a longer time of oxidation, a non-adherent duplex NiO scale was formed. The two layers of the duplex scales were different in color. NiO particles were observed in most of the pores of the porous-nickel samples. Finally, the linear oxidation kinetics and the formation of porous non-adherent duplex oxide scales on the inhomogeneous nickel substrates demonstrated that the addition of new layers of NiO occurred at the scale/metal interface due to the thermodynamically possible reaction between Ni and the molecular oxygen migrating inwardly.

Oxidation characteristics of porous-nickel prepared by powder metallurgy and cast-nickel at 1273 K in air for total oxidation time of 100 h.

Science.gov (United States)

Mohamed, Lamiaa Z; Ghanem, Wafaa A; El Kady, Omayma A; Lotfy, Mohamed M; Ahmed, Hafiz A; Elrefaie, Fawzi A

2017-11-01

The oxidation behavior of two types of inhomogeneous nickel was investigated in air at 1273 K for a total oxidation time of 100 h. The two types were porous sintered-nickel and microstructurally inhomogeneous cast-nickel. The porous-nickel samples were fabricated by compacting Ni powder followed by sintering in vacuum at 1473 K for 2 h. The oxidation kinetics of the samples was determined gravimetrically. The topography and the cross-section microstructure of each oxidized sample were observed using optical and scanning electron microscopy. X-ray diffractometry and X-ray energy dispersive analysis were used to determine the nature of the formed oxide phases. The kinetic results revealed that the porous-nickel samples had higher trend for irreproducibility. The average oxidation rate for porous- and cast-nickel samples was initially rapid, and then decreased gradually to become linear. Linear rate constants were 5.5 × 10 -8  g/cm 2  s and 3.4 × 10 -8  g/cm 2  s for the porous- and cast-nickel samples, respectively. Initially a single-porous non-adherent NiO layer was noticed on the porous- and cast-nickel samples. After a longer time of oxidation, a non-adherent duplex NiO scale was formed. The two layers of the duplex scales were different in color. NiO particles were observed in most of the pores of the porous-nickel samples. Finally, the linear oxidation kinetics and the formation of porous non-adherent duplex oxide scales on the inhomogeneous nickel substrates demonstrated that the addition of new layers of NiO occurred at the scale/metal interface due to the thermodynamically possible reaction between Ni and the molecular oxygen migrating inwardly.

Functionalization of nickel nanowires with a fluorophore aiming at new probes for multimodal bioanalysis.

Science.gov (United States)

Pinheiro, Paula C; Sousa, Célia T; Araújo, João P; Guiomar, António J; Trindade, Tito

2013-11-15

This work reports research on the development of bimodal magnetic and fluorescent 1D nanoprobes. First, ferromagnetic nickel nanowires (NiNW) have been prepared by Ni electrodeposition in an anodic aluminum oxide (AAO) template. The highly ordered self-assembled AAO nanoporous templates were fabricated using a two-step anodization method of aluminum foil. The surface of the NiNW were then modified with polyethyleneimine (PEI) which was previously labeled with an organic dye (fluorescein isothiocyanate: FITC) via covalent bonding. The ensuing functionalized NiNW exhibited the characteristic green fluorescence of FITC and could be magnetically separated from aqueous solutions by using a NdFeB magnet. Finally, the interest of these bimodal NiNW as nanoprobes for in vitro cell separation and biolabeling was preliminary assessed in a proof of principle experiment that involved the attachment of biofunctionalized NiNW to blood cells. Copyright © 2013 Elsevier Inc. All rights reserved.

Technetium electrodeposition from aqueous formate solutions at graphite electrode: electrochemical study

International Nuclear Information System (INIS)

Maslennikov, A.; Peretroukhine, V.; Masson, M.; Lecomte, M.

1999-01-01

Recovery of technetium from aqueous formate buffer solutions of ionic strength μ = 1.0 was studied in the pH interval from 1.6 to 7.5 at graphite cathode in an electrolytic cell with separated compartments was studied, using cyclic voltammetry (CV) and inverse stripping voltammetry (ISV) techniques. It has been shown that Tc electrodeposition process becomes possible at the potentials of graphite cathode E cath. 1/2 = -0.72±0.02 V/SCE and was pH independent in the interval pH = 3.46-7.32. Mechanism of electrodeposition, including Tc(VII)/Tc(IV) reduction in the solution followed by Tc(IV) hydrolysis at the electrode surface with formation of hydrated Tc oxide cathodic deposit has been proposed. The further precision of the Tc(VII) electrochemical reduction mechanism in formate buffer media and optimization of the electrodeposition process seems to be possible using additional analytical facilities except electrochemical methods. (orig.)

Electrodeposition synthesis and electrochemical properties of nanostructured {gamma}-MnO{sub 2} films

Energy Technology Data Exchange (ETDEWEB)

Chou, Shulei; Cheng, Fangyi; Chen, Jun [Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071 (China)

2006-11-08

The thin films of carambola-like {gamma}-MnO{sub 2} nanoflakes with about 20nm in thickness and at least 200nm in width were prepared on nickel sheets by combination of potentiostatic and cyclic voltammetric electrodeposition techniques. The as-prepared MnO{sub 2} nanomaterials, which were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were used as the active material of the positive electrode for primary alkaline Zn/MnO{sub 2} batteries and electrochemical supercapacitors. Electrochemical measurements showed that the MnO{sub 2} nanoflake films displayed high potential plateau (around 1.0V versus Zn) in primary Zn/MnO{sub 2} batteries at the discharge current density of 500mAg{sup -1} and high specific capacitance of 240Fg{sup -1} at the current density of 1mAcm{sup -2}. This indicated the potential application of carambola-like {gamma}-MnO{sub 2} nanoflakes in high-power batteries and electrochemical supercapacitors. The growth process for the one- and three-dimensional nanostructured MnO{sub 2} was discussed on the basis of potentiostatic and cyclic voltammetric techniques. The present synthesis method can be extended to the preparation of other nanostructured metal-oxide films. (author)

PENGARUH JENIS ANODA PADA PROSES PEMULIHAN LOGAM NIKEL DARI TIRUAN AIR LIMBAH ELECTROPLATING MENGGUNAKAN SEL ELEKTRODEPOSISI

Directory of Open Access Journals (Sweden)

Djaenudin Dhaenudin

2013-11-01

Full Text Available EFFECT OF ANODES TYPES ON NICKEL RECOVERY FROM SYNTHETIC ELECTROPLATING WASTE ELECTRODEPOSITION CELLS. A study concerning the recovery of nickel from electroplating wastewater artificial solution. The study was conducted with a batch system using electrodeposition cell consisting of two spaces separated by water hyacinth leaf, copper cathode plate, H2SO4 solution anolyte, catholyte solution of NiSO4 plus NaCl supporting electrolyte and anode varied. Electrodeposition performed at the direct current of 5V power for 4 hours each run. The research objective was to obtain the best anode in nickel electrodeposition process of electroplating waste artificial solution. Graphite, stainless steel type AISI 316 and the lead were used as a variation of the anode. Concentration of nickel in the catholyte at baseline 2200 mg/L. The results showed that the anode was a graphite anode with best value decreased by 72.44% nickel concentration, deposition of nickel on the cathode of 0.188 grams and specific energy values ​​of 6.1625 kWh/kg.nickel.   Telah dilakukan penelitian tentang pemulihan logam nikel dari larutan tiruan air limbah electroplating. Penelitian dilakukan dengan sistem batch menggunakan sel elektrodeposisi yang terdiri dari dua ruang yang dipisahkan dengan daun eceng gondok, katoda pelat tembaga, anolit larutan H2SO4, katolit larutan NiSO4 ditambah elektrolit pendukung larutan NaCl dan anoda divariasikan. Elektrodeposisi dilakukan pada listrik searah sebesar 5V selama 4 jam setiap tempuhan. Tujuan penelitian adalah memperoleh anoda terbaik pada proses elektrodeposisi nikel dari larutan tiruan limbah electroplating. Grafit, Stainless Steel  tipe AISI 316 dan timbal digunakan sebagai variasi jenis anoda. Konsentrasi nikel dalam katolit pada awal penelitian 2200 mg/L. Hasil penelitian menunjukkan bahwa anoda grafit merupakan anoda yang paling baik dengan nilai penurunan konsentrasi nikel sebesar 72,44%, deposisi nikel di katoda sebesar 0

In situ diffraction studies of electrode surface structure during gold electrodeposition

International Nuclear Information System (INIS)

Magnussen, O.M.; Krug, K.; Ayyad, A.H.; Stettner, J.

2008-01-01

Surface X-ray scattering (SXS) in transmission geometry provides a valuable tool for in situ structural studies of electrochemical interfaces under reaction conditions, as illustrated here for homoepitaxial electrodeposition on Au(1 0 0) and Au(1 1 1) electrodes. Employing diffusion-limited deposition conditions to separate the effects of potential and deposition rate, a mutual interaction between the interface structure and the growth behavior is found. Time-dependent SXS measurements during Au(1 0 0) homoepitaxy show with decreasing potential transitions from step flow to layer-by-layer growth, then to multilayer growth, and finally back to layer-by-layer growth. This complex growth behavior can be explained within the framework of kinetic growth theory by the effect of potential, Cl adsorbates and the Au surface structure, specifically the presence of the surface reconstruction, on the Au surface mobility. Conversely, the electrodeposition process influences the structure of the reconstructed Au surface, as illustrated for Au(1 1 1), where a significant deposition-induced compression of the Au surface layer as compared to Au(1 1 1) surfaces under ultrahigh vacuum conditions or in Au-free electrolyte is found. This compression increases towards more negative potentials, which may be explained by a release of potential-induced surface stress

Oral nickel exposure may induce Type I hypersensitivity reaction in nickel-sensitized subjects.

Science.gov (United States)

Büyüköztürk, Suna; Gelincik, Aslı; Ünal, Derya; Demirtürk, Mustafa; Çelik, Dolay Damla; Erden, Sacide; Çolakoğlu, Bahattin; Erdem Kuruca, Serap

2015-05-01

Little is known about the clinical and immunological changes in the nickel allergic patients with systemic symptoms. We aimed to evaluate T helper cell responses of patients with different clinical presentations due to nickel. Patients having various allergic symptoms and positive patch test results to nickel and 20 controls underwent skin prick tests with nickel. IL-10, IL-4, IL-5 and IFN-gamma were measured in the culture supernatants of PBMC stimulated by nickel during lymphocyte proliferation test (LTT). 69 patients (56 female, mean age: 49.2 ± 13.1), 97% having nickel containing dental devices and 20 controls (8 female, mean age 34.9 ± 12.06) were evaluated. Skin prick tests with nickel were positive in 70% of the patients (pnickel. Nickel containing dental alloys and oral nickel intake seem to trigger systemic symptoms in previously nickel sensitized patients. Copyright © 2015 Elsevier B.V. All rights reserved.

Morphological and magnetic properties of cobalt nanoclusters electrodeposited onto HOPG

International Nuclear Information System (INIS)

Rivera, M.; Rios-Reyes, C.H.; Mendoza-Huizar, L.H.

2008-01-01

In this work, the morphological and magnetic properties of cobalt nanoclusters obtained from two different sulphate electrolyte solutions were studied. The aggregates were electrodeposited onto highly oriented pyrolytic graphite electrodes in overpotential conditions, in order to investigate the cationic influence on the final properties of the aggregates. In both cases, scanning electron microscopy and atomic force microscopy showed random isolated clusters on the electrode surface, where size variations were determined by the electrolyte solution. By using magnetic force microscopy, the distribution of the electrodeposited magnetic material was more clearly observed which gave some insights on the growth mechanism of these aggregates.

A study on corrosion resistance of electrodeposited Zn-base alloy steel sheet

International Nuclear Information System (INIS)

Park, Hyun Soon

1986-01-01

Effects of electrodeposits of Zn-Ni or Zn-Co alloy with small amounts of Mo or W in sulphate bath on the corrosion resistance of plated steel sheet were studied. 1) The electrodeposition of Zn-Ni and Zn-Co alloy shows both anomalous codeposition behavior. The grade of anomalous codeposition of Zn-Co alloy rises with adding Mo or W in bath. 2) The Ni content in Zn-Ni deposits increases with decreasing cathode current density and with increasing bath temperature. 3) In case of electroplating of Zn-Co, the increase of cathodic current density of bath bring on increasing of the Co content, but on decreasing of the Mo content in deposits. And rising bath temperature increases both Co and Mo deposits. 4) The corrosion resistance of the Zn-Ni electrodeposited steel sheet is shown a maximum at the Ni content of 10-17%. The structure of Zn-Ni of these composition range was finegrained γ-phase. 5) The corrosion resistance of the Zn-Co electrodeposited steel sheet is improved with increasing Co content. The corrosion resistance of the Zn-Co-Mo or Zn-Co-W deposits electroplated by proper plating conditions was improved much more than that of Zn-Co deposits. (Author)

Electrodeposited Germanium/Carbon Composite as an Anode Material for Lithium Ion Batteries

International Nuclear Information System (INIS)

Kim, Sang-Wan; Ngo, Duc Tung; Heo, Jaeyeong; Park, Choong-Nyeon; Park, Chan-Jin

2017-01-01

Highlights: • Electrodeposition was applied for the synthesis of Ge/C composite. • High coulombic efficiency of ∼85% in the first cycle was attained for Ge/C composite. • Full cell of Ge/C-LiCoO 2 exhibits excellent electrochemical performance, without pre-lithiation of Ge/C. - Abstract: We demonstrate the synthesis of nano Ge/C composite using a facile and cost-effective electrochemical deposition method, and its application as an anode material in Li-ion batteries. Nano Ge/C composite is electrodeposited directly on Cu foil in ethylene glycol containing GeCl 4 and carbon black. The Ge particles with an average size of ∼20 nm are uniformly covered with carbon. Compared with the pure Ge electrode, the Ge/C electrode exhibits a higher first reversible capacity of 1224 mA g −1 , and maintains a capacity of 1095 mAh g −1 at 0.1C over 50 cycles. Even at the high rate of 2C, the capacity of the Ge/C electrode is still high at 972 mAh g −1 . The presence of carbon black and pores in the Ge/C electrode improves the conductivity of the electrode, and mitigates the stress inside the electrode by supplying buffer volume, leading to the enhanced electrochemical characteristics of the electrode. Further, the full Li-ion cell composed of Ge/C anode and LiCoO 2 cathode exhibits good cyclability, rate capability, and coulombic efficiency.

Excessive nickel release from mobile phones--a persistent cause of nickel allergy and dermatitis.

Science.gov (United States)

Jensen, Peter; Johansen, Jeanne D; Zachariae, Claus; Menné, Torkil; Thyssen, Jacob P

2011-12-01

Despite the political intention to limit nickel allergy and dermatitis in Europeans, nickel allergy remains frequent. There are several explanations for the persistence of nickel allergy and dermatitis, including the increasing use of mobile phones. Before regulation of nickel release from mobile phones, we showed that eight (19.5%) of 41 mobile phones marketed in Denmark between 2003 and 2007 released nickel in concentrations that may result in nickel allergy and dermatitis. In 2009, the EU Nickel Directive was revised to include nickel-releasing mobile phones. To investigate the proportion of mobile phones sold in Denmark that release nickel after regulation. Metallic parts from 50 randomly selected mobile phones currently for sale in Denmark were tested for nickel release by use of the dimethylglyoxime (DMG)-nickel spot test. Nine (18%) phones showed at least one positive DMG test reaction and two phones had more than one DMG test-positive spot. Apparently, the proportion of mobile phones with significant nickel release remains unchanged, despite the 2009 revision of the EU Nickel Directive. We encourage manufacturers to measure nickel release from metallic components used in the assembly of mobile phones to ensure safe products. © 2011 John Wiley & Sons A/S.

Copper-zinc electrodeposition in alkaline-sorbitol medium: Electrochemical studies and structural, morphological and chemical composition characterization

Science.gov (United States)

de Almeida, M. R. H.; Barbano, E. P.; de Carvalho, M. F.; Tulio, P. C.; Carlos, I. A.

2015-04-01

The galvanostatic technique was used to analyze the electrodeposition of Cu-Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu-Zn films were whitish golden, light golden, golden/gray depending on the Cu2+/Zn2+ ratios in the electrodeposition bath, deposition current density (jdep) and charge density (qdep). The highest current efficiency was ∼54.0%, at jdep -1.0 mA cm-2 and qdep 0.40 C cm-2 in the Cu70/Zn30 bath. Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower jdep. Also, for same jdep the Cu content increased with qdep. Scanning electron microscopy showed that Cu-Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at jdep -20.0 mA cm-2 and qdep 10.0 C cm-2. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu-Zn electrodeposits obtained at jdep -8.0, -20.0 and -40.0 mA cm-2, in each case, with qdep 2.0 and 10.0 C cm-2, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn5 and Cu5Zn8. Galvanostatic electrodeposits of Cu-Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications, especially for decorative purposes.

2010 ELECTRODEPOSITION GORDON RESEARCH CONFERENCE, AUGUST 1-6, 2010

Energy Technology Data Exchange (ETDEWEB)

Peter Searson

2010-08-06

The 2010 Gordon Conference on Electrodeposition will present cutting-edge research on electrodeposition with emphasis on (i) advances in basic science, (ii) developments in next-generation technologies, and (iii) new and emerging areas. The Conference will feature a wide range of topics, from atomic scale processes, nucleation and growth, thin film deposition, and electrocrystallization, to applications of electrodeposition in devices including microelectronics, solar energy, and power sources. The Conference will bring together investigators from a wide range of scientific disciplines, including chemical engineering, materials science and engineering, physics, and chemistry. The Conference will feature invited speakers at the forefront of the field, and a late-breaking news session that will provide the opportunity for graduate students, post-docs, and junior faculty to participate. The collegial atmosphere of this Conference, with scientific talks and poster sessions, as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to discuss current issues and promotes cross-disciplinary collaborations in the various research areas represented. The Conference will be held at Colby-Sawyer College, located in the Mt. Kearsarge-Lake Sunapee Region of New Hampshire. The surrounding mountains, forests, and lakes provide a beautiful setting for this conference. The attendance is limited so early application is strongly advised.

Excessive nickel release from mobile phones--a persistent cause of nickel allergy and dermatitis

DEFF Research Database (Denmark)

Jensen, Peter; Johansen, Jeanne D; Zachariae, Claus

2011-01-01

Despite the political intention to limit nickel allergy and dermatitis in Europeans, nickel allergy remains frequent. There are several explanations for the persistence of nickel allergy and dermatitis, including the increasing use of mobile phones. Before regulation of nickel release from mobile...... phones, we showed that eight (19.5%) of 41 mobile phones marketed in Denmark between 2003 and 2007 released nickel in concentrations that may result in nickel allergy and dermatitis. In 2009, the EU Nickel Directive was revised to include nickel-releasing mobile phones....

Excessive nickel release from mobile phones--a persistent cause of nickel allergy and dermatitis

DEFF Research Database (Denmark)

Jensen, Peter; Johansen, Jeanne D; Zachariae, Claus

2011-01-01

phones, we showed that eight (19.5%) of 41 mobile phones marketed in Denmark between 2003 and 2007 released nickel in concentrations that may result in nickel allergy and dermatitis. In 2009, the EU Nickel Directive was revised to include nickel-releasing mobile phones.......Despite the political intention to limit nickel allergy and dermatitis in Europeans, nickel allergy remains frequent. There are several explanations for the persistence of nickel allergy and dermatitis, including the increasing use of mobile phones. Before regulation of nickel release from mobile...

Synthesis of Nickel and Nickel Hydroxide Nano powders by Simplified Chemical Reduction

International Nuclear Information System (INIS)

Tientong, J.; Garcia, S.; Thurber, C.R.; Golden, T.D.

2014-01-01

Nickel nano powders were synthesized by a chemical reduction of nickel ions with hydrazine hydrate at ph ∼ 12.5. Sonication of the solutions created a temperature of 54-65 °C to activate the reduction reaction of nickel nanoparticles. The solution ph affected the composition of the resulting nanoparticles. Nickel hydroxide nanoparticles were formed from an alkaline solution (ph ∼10) of nickel-hydrazine complexed by dropwise titration. X-ray diffraction of the powder and the analysis of the resulting Williamson-Hall plots revealed that the particle size of the powders ranged from 12 to 14 nm. Addition of polyvinylpyrrolidone into the synthesis decreased the nickel nanoparticle size to approximately 7 nm. Dynamic light scattering and scanning electron microscopy confirmed that the particles were in the nanometer range. The structure of the synthesized nickel and nickel hydroxide nanoparticles was identified by X-ray diffraction and Fourier transform infrared spectroscopy.

A radiochemical study of gold electrodeposition kinetics in alkaline cyanide solutions

International Nuclear Information System (INIS)

Poshkus, D.; Agafonovas, G.; Zhebrauskas, A.

1995-01-01

Kinetics of gold electrodeposition from alkaline cyanide solutions was investigated by the use of labelled gold 195 atoms. The absorption of cyanide containing species from alkaline cyanide and dicyanoaurate solutions on a gold electrode by the use of labelled carbon atoms was investigated. Polarization curves of anodic dissolution and cathodic deposition of gold in alkaline cyanide solutions were obtained. The values of standard potential, exchange current density, transfer coefficient and standard polarization rate were determined from polarization curves. The errors in current density caused by the nuclear disintegration statistics were evaluated. 28 refs., 1 tab., 4 figs

Nickel concentrations in fingernails as a measure of occupational exposure to nickel

DEFF Research Database (Denmark)

Peters, K; Gammelgaard, Bente; Menné, T

1991-01-01

in nails (p less than 0.001). The difference between the 2 levels was also significant (p less than 0.001). No correlation between the nickel concentration in fingernails and the duration of exposure could be demonstrated. It was concluded that the higher the nickel level in the fingernails, the greater...... is the possibility that the person is occupationally exposed to nickel. Nail analysis is suggested as a measure of occupational exposure to nickel.......The nickel concentration in fingernails from 2 groups of people occupationally exposed to nickel was determined. In one group, comprising 83 persons moderately exposed to nickel, the mean +/- standard deviation (SD) was 29.2 micrograms/g +/- 56.7 micrograms/g and the median 13.8 micrograms/g (range...

Nickel nanostructured materials from liquid phase photodeposition

International Nuclear Information System (INIS)

Giuffrida, Salvatore; Condorelli, Guglielmo G.; Costanzo, Lucia L.; Ventimiglia, Giorgio; Nigro, Raffaella Lo; Favazza, Maria; Votrico, Enrico; Bongiorno, Corrado; Fragala, Ignazio L.

2007-01-01

Liquid Phase Photo-Deposition (LPPD) technique has been used to obtain both colloidal particles and thin films of metallic and chloride nickel from solutions of only precursor Ni(acac) 2 (acac=2,4-pentandionato). Metallic nickel was obtained from ethanol solutions by direct nickel(II) photoreduction at 254 nm and by acetone sensitised reaction at 300 nm. In this latter process the rate was higher than in the first one. NiCl 2 was formed from CCl 4 solution by a solvent-initiated reaction. TEM analysis, performed on colloidal particles of nickel, showed that their dimensions are in the range 2-4 nm. The films did not present carbon contamination and were characterized by AFM, XPS and GIXRD. Metallic films consisted of particles of 20-40 nm that are the result of the aggregation of smaller crystallites (4-5 nm). Larger agglomerations (around 200 nm) have been observed for NiCl 2 films

Nickel nanostructured materials from liquid phase photodeposition

Energy Technology Data Exchange (ETDEWEB)

Giuffrida, Salvatore, E-mail: sgiuffrida@unict.it; Condorelli, Guglielmo G.; Costanzo, Lucia L.; Ventimiglia, Giorgio [Universita degli Studi di Catania and INSTM UdR di, Dipartimento di Scienze Chimiche (Italy); Nigro, Raffaella Lo [IMM-CNR (Italy); Favazza, Maria; Votrico, Enrico [Universita degli Studi di Catania and INSTM UdR di, Dipartimento di Scienze Chimiche (Italy); Bongiorno, Corrado [IMM-CNR (Italy); Fragala, Ignazio L. [Universita degli Studi di Catania and INSTM UdR di, Dipartimento di Scienze Chimiche (Italy)

2007-08-15

Liquid Phase Photo-Deposition (LPPD) technique has been used to obtain both colloidal particles and thin films of metallic and chloride nickel from solutions of only precursor Ni(acac){sub 2} (acac=2,4-pentandionato). Metallic nickel was obtained from ethanol solutions by direct nickel(II) photoreduction at 254 nm and by acetone sensitised reaction at 300 nm. In this latter process the rate was higher than in the first one. NiCl{sub 2} was formed from CCl{sub 4} solution by a solvent-initiated reaction. TEM analysis, performed on colloidal particles of nickel, showed that their dimensions are in the range 2-4 nm. The films did not present carbon contamination and were characterized by AFM, XPS and GIXRD. Metallic films consisted of particles of 20-40 nm that are the result of the aggregation of smaller crystallites (4-5 nm). Larger agglomerations (around 200 nm) have been observed for NiCl{sub 2} films.

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Indian Academy of Sciences (India)

flower-like nickel sulphide nanocrystals through decomposing bis(thiourea) nickel(II) ... behaviors of jet electrodeposition Ni–W–P alloy. J K Yu, Y H Wang, G Z Xing ... Ultrasonic investigations of some bismuth borate glasses doped with Al2O3.

Early stages of oxidation of ion-implanted nickel at high temperature

International Nuclear Information System (INIS)

Peide, Z.; Grant, W.A.; Procter, R.P.M.

1981-01-01

The early stages of oxidation of nickel implanted with nickel, chromium, or lithium ions in oxygen at 1100 0 C have been studied using various electron-optical techniques. The unimplanted metal develops initially a fine-grained, convoluted scale having a ridged, cellular structure. Subsequently, the oxide grains increase in size significantly and oxidation becomes predominantly controlled by diffusion of Ni /sup 2+/ ions across a compact, columnar scale. Implantation of the surface with nickel ions has no significant effect on the initial oxidation behavior. However, after implantation with chromium or lithium ions, the development of the NiO scale is, in the early stages of oxidation, suppressed by formation of NiCr 2 O 4 or LiO 2 nodules, respectively. Subsequently, the implanted species are incorporated into the steady-state NiO scale where they dope the oxide and thus influence the diffusion rate of Ni /sup 2+/ ions through it. As would be predicted, the steady-state oxidation rate of chromium-implanted nickel is increased while that of lithium- implanted nickel is decreased compared with that of the unimplanted metal

Effect of nickel introduced by electroplating on pyrocarbon deposition of carbon-fiber preforms

Directory of Open Access Journals (Sweden)

Ren Yancai

2014-08-01

Full Text Available In order to improve the deposition rate and microstructure of pyrocarbon, nickel was introduced by electroplating on carbon fibers and used as a catalyst during the deposition of pyrocarbon at 1000 °C using methane as a precursor gas. The distribution of nickel catalyst and the microstructure of pyrocarbon were characterized by scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, X-ray diffraction (XRD, and Raman micro-spectrometry. Results show that nano-sized nickel particles could be well distributed on carbon fibers and the pyrocarbon deposited catalytically had a smaller d002 value and a higher graphitization degree compared with that without catalyst. In addition, the deposition rate of pyrocarbon in each hour was measured. The deposition rate of pyrocarbon in the first hour was more than 10 times when carbon cloth substrates were doped with nickel catalysts as compared to the pure carbon cloths. The pyrocarbon gained by rapid deposition may include two parts, which are generation directly on the nickel catalyst and formation with the carbon nanofibers as crystal nucleus.

Stress control in electrodeposited CoFe films—Experimental study and analytical model

International Nuclear Information System (INIS)

Brankovic, Stanko R.; Kagajwala, Burhanuddin; George, Jinnie; Majkic, Goran; Stafford, Gery; Ruchhoeft, Paul

2012-01-01

Work investigating the effect of saccharin as an additive on growth stress and structure of electrodeposited CoFe films is presented. The saccharin concentrations were in the range between 0 g L −1 and 1.5 g L −1 . The stress measurements are performed in situ during electrodeposition of CoFe films using cantilever-bending method (curvature measurements). The structure of CoFe films was studied by transmission electron microscopy and X-ray diffraction. Results show that growth stress is a decreasing function of saccharin concentration. No appreciable change in composition, grain size, orientation or texture of CoFe films are observed with increasing saccharin content in solution. The growth stress dependence on saccharin concentration is discussed within the framework of analytical model, which directly links the observed stress decrease with the apparent saccharin coverage of the CoFe film surface during the electrodeposition process.

Aluminium Electrodeposition from Ionic Liquid: Effect of Deposition Temperature and Sonication †

Directory of Open Access Journals (Sweden)

Enrico Berretti

2016-08-01

Full Text Available Since their discovery, ionic liquids (ILs have attracted a wide interest for their potential use as a medium for many chemical processes, in particular electrochemistry. As electrochemical media they allow the electrodeposition of elements that are impossible to reduce in aqueous media. We have investigated the electrodeposition of aluminium from 1-butyl-3-methyl-imidazolium chloride ((BmimCl/AlCl3 (40/60 mol % as concerns the effect of deposition parameters on the quality of the deposits. Thick (20 μm aluminium coatings were electrodeposited on brass substrates at different temperatures and mixing conditions (mechanical stirring and sonication. These coatings were investigated by means of scanning electron microscope, roughness measurements, and X-ray diffraction to assess the morphology and the phase composition. Finally, electrochemical corrosion tests were carried out with the intent to correlate the deposition parameters to the anti-corrosion properties.

Effect of pretreatments on electrodeposited epoxy coatings for electronic industries

Directory of Open Access Journals (Sweden)

Sironmani Palraj

2016-02-01

Full Text Available Waterborne epoxy coatings were prepared on aluminium (Al surfaces by cathodic electro-deposition on the pretreated surface of pickling, phosphating, chromating and anodizing. The electro-deposition experiments were done at two different voltages, 15 V and 25 V at room temperature in 10% epoxy coating formulations. Corrosion and thermal behavior of these coatings were investigated using electrochemical impedance spectroscopy (EIS and thermo gravimetric analysis (TGA. The coating exhibits better corrosion resistance in anodized Al surface than the other. But, TGA studies show that the thermal stability is higher in anodized and chromated Al surfaces. The surface morphology of these coatings were analyzed by SEM and AFM studies.

Characterization and assessment of dermal and inhalable nickel exposures in nickel production and primary user industries.

Science.gov (United States)

Hughson, G W; Galea, K S; Heim, K E

2010-01-01

The aim of this study was to measure the levels of nickel in the skin contaminant layer of workers involved in specific processes and tasks within the primary nickel production and primary nickel user industries. Dermal exposure samples were collected using moist wipes to recover surface contamination from defined areas of skin. These were analysed for soluble and insoluble nickel species. Personal samples of inhalable dust were also collected to determine the corresponding inhalable nickel exposures. The air samples were analysed for total inhalable dust and then for soluble, sulfidic, metallic, and oxidic nickel species. The workplace surveys were carried out in five different workplaces, including three nickel refineries, a stainless steel plant, and a powder metallurgy plant, all of which were located in Europe. Nickel refinery workers involved with electrolytic nickel recovery processes had soluble dermal nickel exposure of 0.34 microg cm(-2) [geometric mean (GM)] to the hands and forearms. The GM of soluble dermal nickel exposure for workers involved in packing nickel salts (nickel chloride hexahydrate, nickel sulphate hexahydrate, and nickel hydroxycarbonate) was 0.61 microg cm(-2). Refinery workers involved in packing nickel metal powders and end-user powder operatives in magnet production had the highest dermal exposure (GM = 2.59 microg cm(-2) soluble nickel). The hands, forearms, face, and neck of these workers all received greater dermal nickel exposure compared with the other jobs included in this study. The soluble nickel dermal exposures for stainless steel production workers were at or slightly above the limit of detection (0.02 microg cm(-2) soluble nickel). The highest inhalable nickel concentrations were observed for the workers involved in nickel powder packing (GM = 0.77 mg m(-3)), although the soluble component comprised only 2% of the total nickel content. The highest airborne soluble nickel exposures were associated with refineries using

Effect of surfactant concentration in the electrolyte on the tribological properties of nickel-tungsten carbide composite coatings produced by pulse electro co-deposition

Energy Technology Data Exchange (ETDEWEB)

Kartal, Muhammet, E-mail: kartal@sakarya.edu.tr [Sakarya University, Engineering Faculty, Metallurgical & Materials Engineering Department, Esentepe Campus, 54187 Sakarya (Turkey); Uysal, Mehmet [Sakarya University, Engineering Faculty, Metallurgical & Materials Engineering Department, Esentepe Campus, 54187 Sakarya (Turkey); Gul, Harun [Duzce University, Gumusova Vocational School, 81850 Duzce (Turkey); Alp, Ahmet; Akbulut, Hatem [Sakarya University, Engineering Faculty, Metallurgical & Materials Engineering Department, Esentepe Campus, 54187 Sakarya (Turkey)

2015-11-01

Highlights: • Effect of surfactant concentration on the co-deposited WC was investigated. • In the Ni matrix significantly high hardness was achieved by WC co-deposition. • Optimum surfactant resulted in obtaining superior wear resistance in the Ni. • Friction coefficient was decreased by WC co-deposition in the Ni matrix. - Abstract: A nickel plating bath containing WC particles was used to obtain hard and wear-resistant particle reinforced Ni/WC MMCs on steel surfaces for anti-wear applications. Copper substrates were used for electro co-deposition of Ni matrix/WC with the particle size of <1 μm tungsten carbide reinforcements. The influence of surfactant (sodium dodecyl sulfate, SDS) concentration on particle distribution, microhardness and wear resistance of composite coatings has been studied. The nickel films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of the surfactant on the zeta potential, co-deposition and distribution of WC particles in the nickel matrix, as well as the tribological properties of composite coatings were also investigated. The tribological behaviors of the electrodeposited WC composite coatings sliding against M50 steel ball (Ø 10 mm) were examined on a CSM Instrument. All friction and wear tests were performed without lubrication at room temperature and in the ambient air (relative humidity 55–65%).

Effect of electrodeposition potential on composition and morphology ...

Indian Academy of Sciences (India)

The underpotential deposition mechanism of Cu–Se and In–Se phases was observed in ... Thin films; cyclic voltammetry; CuInGaSe (CIGS); solar cell; electrodeposition. 1. ... trode was a Pt spiral wire and the working electrode was. 735 ...

A Nose for Hydrogen Gas: Fast, Sensitive H2 Sensors Using Electrodeposited Nanomaterials.

Science.gov (United States)

Penner, Reginald M

2017-08-15

Hydrogen gas (H 2 ) is odorless and flammable at concentrations above 4% (v/v) in air. Sensors capable of detecting it rapidly at lower concentrations are needed to "sniff" for leaked H 2 wherever it is used. Electrical H 2 sensors are attractive because of their simplicity and low cost: Such sensors consist of a metal (usually palladium, Pd) resistor. Exposure to H 2 causes a resistance increase, as Pd metal is converted into more resistive palladium hydride (PdH x ). Sensors based upon Pd alloy films, developed in the early 1990s, were both too slow and too insensitive to meet the requirements of H 2 safety sensing. In this Account, we describe the development of H 2 sensors that are based upon electrodeposited nanomaterials. This story begins with the rise to prominence of nanowire-based sensors in 2001 and our demonstration that year of the first nanowire-based H 2 sensor. The Pd nanowires used in these experiments were prepared by electrodepositing Pd at linear step-edge defects on a graphite electrode surface. In 2005, lithographically patterned nanowire electrodeposition (LPNE) provided the capability to pattern single Pd nanowires on dielectrics using electrodeposition. LPNE also provided control over the nanowire thickness (±1 nm) and width (±10-15%). Using single Pd nanowires, it was demonstrated in 2010 that smaller nanowires responded more rapidly to H 2 exposure. Heating the nanowire using Joule self-heating (2010) also dramatically accelerated sensor response and recovery, leading to the conclusion that thermally activated H 2 chemisorption and desorption of H 2 were rate-limiting steps in sensor response to and recovery from H 2 exposure. Platinum (Pt) nanowires, studied in 2012, showed an inverted resistance response to H 2 exposure, that is, the resistance of Pt nanowires decreased instead of increased upon H 2 exposure. H 2 dissociatively chemisorbs at a Pt surface to form Pt-H, but in contrast to Pd, it stays on the Pt surface. Pt nanowires

Synthesis, structure characterization and catalytic activity of nickel tungstate nanoparticles

International Nuclear Information System (INIS)

Pourmortazavi, Seied Mahdi; Rahimi-Nasrabadi, Mehdi; Khalilian-Shalamzari, Morteza; Zahedi, Mir Mahdi; Hajimirsadeghi, Seiedeh Somayyeh; Omrani, Ismail

2012-01-01

Graphical abstract: NiWO 4 nanoparticles were prepared via precipitation technique. Experimental parameters of procedure were optimized statistically. Highlights: ► NiWO 4 spherical nanoparticles were synthesized via direct precipitation method. ► Taguchi robust design was used for optimization of synthesis reaction parameters. ► Composition and structural properties of NiWO 4 nanoparticles were characterized. ► EDAX, XRD, SEM, FT-IR, UV–vis and photoluminescence techniques were employed. ► Catalytic activity of the product in a cyclo-addition reaction was investigated. - Abstract: Taguchi robust design was applied to optimize experimental parameters for controllable, simple and fast synthesis of nickel tungstate nanoparticles. NiWO 4 nanoparticles were synthesized by precipitation reaction involving addition of nickel ion solution to the tungstate aqueous reagent and then formation of nickel tungstate nucleolus which are insoluble in aqueous media. Effects of various parameters such as nickel and tungstate concentrations, flow rate of reagent addition and reactor temperature on diameter of synthesized nickel tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The results for analysis of variance (ANOVA) showed that particle size of nickel tungstate can be effectively tuned by controlling significant variables involving nickel and tungstate concentrations and flow rate; while, temperature of the reactor has a no considerable effect on the size of NiWO 4 particles. The ANOVA results proposed the optimum conditions for synthesis of nickel tungstate nanoparticles via this technique. Also, under optimum condition nanoparticles of NiWO 4 were prepared and their structure and chemical composition were characterized by means of EDAX, XRD, SEM, FT-IR spectroscopy, UV–vis spectroscopy, and photoluminescence. Finally, catalytic activity of the nanoparticles in a cycloaddition reaction was examined.

Synthesis, structure characterization and catalytic activity of nickel tungstate nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pourmortazavi, Seied Mahdi, E-mail: pourmortazavi@yahoo.com [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Rahimi-Nasrabadi, Mehdi, E-mail: rahiminasrabadi@gmail.com [Department of Chemistry, Imam Hossein University, Tehran (Iran, Islamic Republic of); Khalilian-Shalamzari, Morteza [Department of Chemistry, Imam Hossein University, Tehran (Iran, Islamic Republic of); Zahedi, Mir Mahdi; Hajimirsadeghi, Seiedeh Somayyeh [Islamic Azad University, Varamin Pishva Branch, Varamin (Iran, Islamic Republic of); Omrani, Ismail [Department of Chemistry, Imam Hossein University, Tehran (Iran, Islamic Republic of)

2012-12-15

Graphical abstract: NiWO{sub 4} nanoparticles were prepared via precipitation technique. Experimental parameters of procedure were optimized statistically. Highlights: Black-Right-Pointing-Pointer NiWO{sub 4} spherical nanoparticles were synthesized via direct precipitation method. Black-Right-Pointing-Pointer Taguchi robust design was used for optimization of synthesis reaction parameters. Black-Right-Pointing-Pointer Composition and structural properties of NiWO{sub 4} nanoparticles were characterized. Black-Right-Pointing-Pointer EDAX, XRD, SEM, FT-IR, UV-vis and photoluminescence techniques were employed. Black-Right-Pointing-Pointer Catalytic activity of the product in a cyclo-addition reaction was investigated. - Abstract: Taguchi robust design was applied to optimize experimental parameters for controllable, simple and fast synthesis of nickel tungstate nanoparticles. NiWO{sub 4} nanoparticles were synthesized by precipitation reaction involving addition of nickel ion solution to the tungstate aqueous reagent and then formation of nickel tungstate nucleolus which are insoluble in aqueous media. Effects of various parameters such as nickel and tungstate concentrations, flow rate of reagent addition and reactor temperature on diameter of synthesized nickel tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The results for analysis of variance (ANOVA) showed that particle size of nickel tungstate can be effectively tuned by controlling significant variables involving nickel and tungstate concentrations and flow rate; while, temperature of the reactor has a no considerable effect on the size of NiWO{sub 4} particles. The ANOVA results proposed the optimum conditions for synthesis of nickel tungstate nanoparticles via this technique. Also, under optimum condition nanoparticles of NiWO{sub 4} were prepared and their structure and chemical composition were characterized by means of EDAX, XRD, SEM, FT-IR spectroscopy, UV

HER Catalytic Activity of Electrodeposited Ni-P Nanowires under the Influence of Magnetic Field

Directory of Open Access Journals (Sweden)

Hung-Bin Lee

2013-01-01

Full Text Available Nickel alloy electrodes both in plane and nanowire morphologies were fabricated by electrodeposition in sulfamate bath. With the increasing concentration of phosphorous acid in the electrolyte, the P content in the deposition increased accordingly. In the meantime, the grain refined and even became amorphous in microstructure as the P content was raised. For the nanowire electrode, vibrating sample magnetometer (VSM measurement showed that its coercivity was anisotropic and decreased with P-content. In addition, the easy axis for magnetization of the electrode was parallel to the axial direction of nanowire. The electrocatalytic activity measurement of the electrode in 0.5 M H2SO4 electrolyte showed that the nanowire electrode had higher activity than the plane one, and the alloying of P in Ni electrode raised its hydrogen evolution reaction (HER performance. The enhanced performance of nanowire electrode was attributed to the smaller and more uniform hydrogen bubbles generated in HER reaction. Finally, the applied magnetic field (3.2 T improved significantly the HER activity of Ni but not Ni-P electrode. By using nanowire morphology and applying magnetic field, the current density at −0.75 V HER stability test of the Ni electrode increased fourfold more than its plane counterpart.

Influence of nickel and beryllium content on swelling behavior of copper irradiated with fast neutrons

Energy Technology Data Exchange (ETDEWEB)

Singh, B.N.; Garner, F.A.; Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Evans, J.H.

1996-10-01

In the 1970`s, the effects of nickel content on the evolution of dislocation microstructures and the formation and growth of voids in Cu-Ni alloys were studied using 1 MeV electrons in a high voltage electron microscope. The swelling rate was found to decrease rapidly with increasing nickel content. The decrease in the swelling rate was associated with a decreasing void growth rate with increasing nickel content at irradiation temperatures up to 450{degrees}C. At 500{degrees}C, both void size and swelling rate were found to peak at 1 and 2% Ni, respectively, and then to decrease rapidly with increasing nickel content. However, recent work has demonstrated that the swelling behavior of Cu-5%Ni irradiated with fission neutrons is very similar for that of pure copper. The present experiments were designed to investigate this apparent discrepancy.

Substitution effects of a carbonated hydroxyapatite biomaterial against intoxication chloride nickel-exposed rats.

Science.gov (United States)

Boulila, Salha; Elfeki, Abdelfattah; Oudadesse, Hassane; Elfeki, Hafed

2015-03-01

This study aimed to investigate the potential effects of a synthetic apatite (carbonated hydroxyapatite) on the detoxification of a group of male "Wistar" rats exposed to nickel chloride. Toxicity was evaluated by rats' bioassay of nickel chloride. Wistar rats received this metal daily by gavage for seven days (4 mg/ml nickel chloride/200 g body weight, BW). To detoxify this organism, a subcutaneous implantation of the apatite is made. The results revealed that exposure to nickel induced oxidative stress, disorders in the balances of ferric phosphocalcic, renal failures, liver toxicity and significant increase in nickel rates in the bones of intoxicated rats. The application of the carbonated hydroxyapatite presented in this study restored those disorders back to normal. The synthetic apatite protected the rats against the toxic effects of nickel by lowering the levels of lipid peroxidation markers and improving the activities of defense enzymes. It also amended ferric and phosphocalcic equilibriums, protected liver and kidney functions and reduced the nickel rate in the bones of the rats. Overall, the results provided strong support for the protective role of carbonated hydroxyapatite in the detoxification of rats exposed to nickel. Those beneficial effects were further confirmed by physico-chemical characterization (X-ray diffraction and infrared spectroscopy), which revealed its property of anionic and cationic substitution, thus supporting its promising candidacy for future biomedical application. The hydroxyapatite is an effective biomaterial to solve health problems, particularly detoxification against metals (nickel).

Nickel as a catalyst for the electro-oxidation of methanol in alkaline medium

Science.gov (United States)

Abdel Rahim, M. A.; Abdel Hameed, R. M.; Khalil, M. W.

The use of Ni as a catalyst for the electro-oxidation of methanol in alkaline medium was studied by cyclic voltammetry. It was found that only Ni dispersed on graphite shows a catalytic activity towards methanol oxidation but massive Ni does not. Ni was dispersed on graphite by the electro-deposition from acidic NiSO 4 solution using potentiostatic and galvanostatic techniques. The catalytic activity of the C/Ni electrodes towards methanol oxidation was found to vary with the amount of electro-deposited Ni. The dependence of the oxidation current on methanol concentration and scan rate was discussed. It was concluded from the electro-chemical measurements and SEM analysis that methanol oxidation starts as Ni-oxide is formed on the electrode surface.

Influence of cooling rate on the development of multiple generations of {gamma}' precipitates in a commercial nickel base superalloy

Energy Technology Data Exchange (ETDEWEB)

Singh, A.R.P. [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Nag, S., E-mail: nag.soumya@gmail.com [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Hwang, J.Y. [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Viswanathan, G.B.; Tiley, J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Dayton, OH (United States); Srinivasan, R. [ExxonMobil Research and Engineering Company, Annandale, NJ (United States); Fraser, H.L. [Center for the Accelerated Maturation of Materials and Department of Materials Science and Engineering, The Ohio State University, Columbus, OH (United States); Banerjee, R. [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States)

2011-09-15

The compositional and microstructural evolution of different generations of {gamma}' precipitates during the continuous cooling of a commercial nickel base superalloy, Rene88DT, has been characterized by three dimensional atom probe tomography coupled with energy-filtered transmission electron microscopy studies. After solutionizing in the single {gamma} phase field, continuous cooling at a very high rate results in a monomodal size distribution of {gamma}' precipitates with a high nucleation density and non-equilibrium compositions. In contrast, a relatively slower cooling rate ({approx} 24 deg. C/min) results in a multi-modal size distribution of {gamma}' precipitates with the larger first generation primary precipitates exhibiting close to equilibrium composition, along with the smaller scale secondary {gamma}' precipitates, exhibiting non-equilibrium composition (excess of Co and Cr, depleted in Al and Ti). The composition of the {gamma} matrix near these precipitates also exhibits similar trends with the composition being closer to equilibrium near the primary precipitates as compared to the secondary precipitates. - Highlights: {yields} Effect of cooling rate on the precipitation of {gamma}' particles in commercial nickel base superalloy. {yields} Couples EFTEM and 3DAP studies to determine the composition and morphology of {gamma}' precipitates. {yields} Determination of near and far field compositional variations within the gamma matrix leading to subsequent precipitation.

Effect of triethanolamine and heliotropin on cathodic polarization of weakly acidic baths and properties of Sn-Ag-Cu alloy electrodeposits

International Nuclear Information System (INIS)

Zhang Jinqiu; An Maozhong; Chang Limin; Liu Guiyuan

2008-01-01

The effect of triethanolamine (TEA) and heliotropin (HT) on the cathodic polarization of weakly acidic baths and the properties of Sn-Ag-Cu alloy electrodeposits were investigated. Lead-free Sn-Ag-Cu solder alloy were electrodeposited in weakly acidic baths (pH 5.5) containing Sn(CH 3 SO 3 ) 2 , AgI, Cu(CH 3 SO 3 ) 2 , K 4 P 2 O 7 , KI, hydroquinone, TEA, HT and methylsulfonic acid (MSA). The cathodic polarization of baths and the properties of electrodeposits were evaluated by Liner sweep voltammetry (LSV), scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results indicate that HT is a main brightening agent that increases the cathodic polarization of baths and refines the grains of electrodeposits; TEA is a complexing agent for copper ions and a brightening promoter that decreases the cathodic polarization of baths and densifies the electrodeposits. The bright, compact, and smooth Sn-Ag-Cu alloy electrodeposits contain 88-95 wt% tin, 5-10 wt% silver and 0.5-2 wt% copper. Organic compounds used in the baths neither adsorb on the electrodeposits surfaces nor are included in the electrodeposits. It can be therefore concluded that the use of both TEA and HT is better than that of them either in the process of electroplating bright Sn-Ag-Cu alloy

Copper electrodeposition from an acidic plating bath containing accelerating and inhibiting organic additives

International Nuclear Information System (INIS)

Pasquale, M.A.; Gassa, L.M.; Arvia, A.J.

2008-01-01

Copper electrodeposition on copper from still plating solutions of different compositions was investigated utilising electrochemical impedance spectroscopy (EIS), cyclic voltammetry, and scanning electron microscopy (SEM). An acid copper sulphate plating base solution was employed either with or without sodium chloride in the presence of a single additive, either polyethylene glycol (PEG) or 3-mercapto-2-propanesulphonic acid (MPSA), and their mixture. Thallium underpotential deposition/anodic stripping was employed to determine the adsorption capability of additives on copper. In the absence of chloride ions, MPSA shows a moderate adsorption on copper, whereas PEG is slightly adsorbed. At low cathodic overpotentials, the simultaneous presence of MPSA and chloride ions accelerates copper electrodeposition through the formation of an MPSA-chloride ion complex in the solution, particularly for about 220 μM sodium chloride. The reverse effect occurs in PEG-sodium chloride plating solutions. In this case, from EIS data the formation of a film that interferes with copper electrodeposition can be inferred. At higher cathodic overpotentials, when copper electrodeposition is under mass transport control, the cathode coverage by a PEG-copper chloride-mediated film becomes either partially or completely detached as the concentration of chloride ions at the negatively charged copper surface diminishes. The copper cathode grain topography at the μm scale depends on the cathodic overpotential, plating solution composition and average current density. Available data about the solution constituents and their adsorption on copper make it possible to propose a likely complex mechanism to understand copper electrodeposition from these media, including the accelerating effect of MPSA and the dynamics of PEG-copper chloride complex adsorbate interfering with the surface mobility of depositing copper ad-ions/ad-atoms

Development of a Micro-Fiber Nickel Electrode for Nickel-Hydrogen Cell

Science.gov (United States)

Britton, Doris L.

1996-01-01

The development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (NiH2) program at the NASA Lewis Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a more efficient and lighter weight electrode for the nickel-hydrogen fuel cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active materials. Initial tests include activation and capacity measurements at different discharge levels followed by half-cell cycle testing at 80 percent depth-of-discharge in a low Earth orbit regime. The electrodes that pass the initial tests are life cycle tested in a boiler plate nickel-hydrogen cell before flightweight designs are built and tested.

Anodic Aluminum Oxide Templates for Nano wires Array Fabrication

International Nuclear Information System (INIS)

Nur Ubaidah Saidin; Kok, K.Y.; Ng, I.K.

2011-01-01

This paper reports on the process developed to fabricate anodic aluminium oxide (AAO) templates suitable for the fabrication of nano wire arrays. Anodization process has been used to fabricate the AAO templates with pore diameters ranging from 15 nm to 30 nm. Electrodeposition of parallel arrays of high aspect ratio nickel nano wires were demonstrated using these fabricated AAO templates. The nano wires produced were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the orientations of the electrodeposited nickel nano wires were governed by the deposition current and electrolyte conditions. (author)

Correlation between crystallographic texture, microstructure and magnetic properties of pulse electrodeposited nanocrystalline Nickel–Cobalt alloys

Energy Technology Data Exchange (ETDEWEB)

Sharma, Amit; Chhangani, Sumit; Madhavan, R.; Suwas, Satyam, E-mail: satyamsuwas@materials.iisc.ernet.in

2017-07-15

Highlights: • Nano-crystalline Ni–Co materials with varying composition has been deposited by pulse electrodeposition. • Overall weakening of <1 1 1> texture and strengthening of <2 0 0> fibre texture is observed with increasing cobalt content. • Higher thermal stability of Ni–70Co is interpreted in terms of low mobility twins and texture. • A clear transition from soft to hard magnetic character is observed with an increase cobalt content. - Abstract: This paper reports the evolution of microstructure and texture in Nickel–Cobalt electrodeposits fabricated by pulse electrodeposition (PED) technique and the correlation of these attributes with the magnetic properties. The structural and microstructural investigation using X-ray diffraction and transmission electron microscopic studies indicate the presence of nanocrystalline grains and nano-twins in the electrodeposits. Convoluted Multiple Whole profile fitting reveals an increase in dislocation density and twin density with increasing cobalt content in the as-deposited samples. Strengthening of <1 1 1> fibre texture and weakening of <2 0 0> fibre texture with increasing cobalt concentration has been observed with X-ray texture analysis. A corresponding significant increase in the saturation magnetization and coercivity observed with increasing cobalt content. A significant improvement in the soft magnetic character in the electrodeposits in terms of increase in saturation magnetization and decrease in coercivity has been observed with thermal annealing.

Influence of citrate ions as complexing agent for electrodeposition of CuInSe{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Chraibi, F. [Universite Libre de Bruxelles (Belgium). Service de Sciences des Materiaux et Electrochimie; Universite Mohammed 5, Rabat (Morocco). Dept. de Physique; Fahoume, M.; Ennaoui, A. [Universite Mohammed 5, Rabat (Morocco). Dept. de Physique; Delplancke, J.L. [Universite Libre de Bruxelles (Belgium). Service de Sciences des Materiaux et Electrochimie

2001-08-16

The preparation of CuInSe{sub 2} thin films by electrodeposition is studied. The effect of sodium citrate (Na{sub 3}C{sub 6}H{sub 5}O{sub 7}) as complexing agent on the electrodeposition of pure copper, indium, selenium and of their ternary alloy is emphasized. Cathodic shifts of the copper and selenium electrodeposition potentials with increasing citrate concentration are observed. On the contrary, the presence of citrate in the electrolyte does not change the indium electrodeposition potential but improves its crystallinity. The surface morphology and the composition of the deposited films are characterized by scanning electron microscopy (SEM). The texture of the deposits and their compositions are analyzed by X-ray diffraction. The formation of CuInSe{sub 2} films with a chalcopyrite structure and good stoichiometry is observed. (orig.)

Biological role of nickel

Energy Technology Data Exchange (ETDEWEB)

Thauer, R K; Diekert, G; Schoenheit, P

1980-01-01

Several enzymes and one cofactor have recently been shown to contain nickel. For example, urease of jack beans has been found to be a nickel protein and factor F/sub 430/ from methanogenic bacteria to be a nickel tetrapyrrole. The biological role of nickel in several organisms is discussed.

SURFACE MODIFICATION OF SEMICONDUCTOR THIN FILM OF TiO2 ON GRAPHITE SUBSTRATE BY Cu-ELECTRODEPOSITION

Directory of Open Access Journals (Sweden)

Fitria Rahmawati

2010-06-01

Full Text Available Surface modification of graphite/TiO2 has been done by mean of Cu electrodeposition. This research aims to study the effect of Cu electrodeposition on photocatalytic enhancing of TiO2. Electrodeposition has been done using CuSO4 0,4 M as the electrolyte at controlled current. The XRD pattern of modified TiO2 thin film on graphite substrate exhibited new peaks at 2θ= 43-44o and 2θ= 50-51o that have been identified as Cu with crystal cubic system, face-centered crystal lattice and crystallite size of 26-30 nm. CTABr still remains in the material as impurities. Meanwhile, based on morphological analysis, Cu particles are dissipated in the pore of thin film. Graphite/TiO2/Cu has higher photoconversion efficiency than graphite/TiO2.   Keywords: semiconductor, graphite/TiO2, Cu electrodeposition

Contaminated nickel scrap processing

International Nuclear Information System (INIS)

Compere, A.L.; Griffith, W.L.; Hayden, H.W.; Johnson, J.S. Jr.; Wilson, D.F.

1994-12-01

The DOE will soon choose between treating contaminated nickel scrap as a legacy waste and developing high-volume nickel decontamination processes. In addition to reducing the volume of legacy wastes, a decontamination process could make 200,000 tons of this strategic metal available for domestic use. Contaminants in DOE nickel scrap include 234 Th, 234 Pa, 137 Cs, 239 Pu (trace), 60 Co, U, 99 Tc, and 237 Np (trace). This report reviews several industrial-scale processes -- electrorefining, electrowinning, vapormetallurgy, and leaching -- used for the purification of nickel. Conventional nickel electrolysis processes are particularly attractive because they use side-stream purification of process solutions to improve the purity of nickel metal. Additionally, nickel purification by electrolysis is effective in a variety of electrolyte systems, including sulfate, chloride, and nitrate. Conventional electrorefining processes typically use a mixed electrolyte which includes sulfate, chloride, and borate. The use of an electrorefining or electrowinning system for scrap nickel recovery could be combined effectively with a variety of processes, including cementation, solvent extraction, ion exchange, complex-formation, and surface sorption, developed for uranium and transuranic purification. Selected processes were reviewed and evaluated for use in nickel side-stream purification. 80 refs

Electrodeposition of gold templated by patterned thiol monolayers

Energy Technology Data Exchange (ETDEWEB)

She, Zhe [EaStCHEM School of Chemistry, University of St. Andrews, KY16 9ST (United Kingdom); Di Falco, Andrea [SUPA, School of Physics and Astronomy, University of St. Andrews, KY16 9SS (United Kingdom); Hähner, Georg [EaStCHEM School of Chemistry, University of St. Andrews, KY16 9ST (United Kingdom); Buck, Manfred, E-mail: mb45@st-andrews.ac.uk [EaStCHEM School of Chemistry, University of St. Andrews, KY16 9ST (United Kingdom)

2016-06-15

Graphical abstract: - Highlights: • First demonstration of electrodeposition/lift-off of gold using thiol monolayers. • Microelectrode structures with large length to width ratio were generated. • Performance of two different patterning techniques was investigated. • Conditions for achieving good contrast in the electrodeposition were established. - Abstract: The electrochemical deposition of Au onto Au substrates modified by self-assembled monolayers (SAMs) was studied by linear sweep voltammetry (LSV), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Patterned SAMs exhibiting electrochemical contrast were prepared by two different methods. One used microcontact printing (μCP) to generate a binary SAM of ω-(4′-methyl-biphenyl-4-yl)-propane thiol (CH{sub 3}-C{sub 6}H{sub 4}-C{sub 6}H{sub 4}-(CH{sub 2}){sub 3}-SH, MBP3) and octadecane thiol (CH{sub 3}(CH{sub 2}){sub 17}SH, ODT). Templated by the SAM, a gold microelectrode structure was electrodeposited featuring a line 15 μm wide and 3 mm long. After transfer to an epoxy substrate the structure proved to be electrically conductive across the full length. The other patterning method applied electron beam lithography (EBL) where electrochemical contrast was achieved by crosslinking molecules in a single component SAM of MBP3. An electron dose above 250 mC/cm{sup 2} results in a high deposition contrast. The choice of parameters for the deposition/lift-off process is found to be more critical for Au compared to Cu studied previously. The origin of the differences and implications for nanoscale patterning are discussed.

Dendrite-Free Electrodeposition and Reoxidation of Lithium-Sodium Alloy for Metal-Anode Battery

Science.gov (United States)

2011-11-01

Dendrite-Free Electrodeposition and Reoxidation of Lithium-Sodium Alloy for Metal-Anode Battery Johanna K. Star 1 , Yi Ding 2 , and Paul A. Kohl ,1, * 1...Journal Article 3. DATES COVERED 01-11-2011 to 01-11-2011 4. TITLE AND SUBTITLE DENDRITE-FREE ELECTRODEPOSITION AND REOXIDATION OF LITHIUM-SODIUM...can short circuit the anode and cathode . Anode- cathode short circuits are especially dangerous when a flammable organic solvent is used as the

Prototype nickel component demonstration. Final report

International Nuclear Information System (INIS)

Boss, D.E.

1994-01-01

We have been developing a process to produce high-purity nickel structures from nickel carbonyl using chemical vapor deposition (CVD). The prototype demonstration effort had been separated into a number of independent tasks to allow Los Alamos National Laboratory (LANL) the greatest flexibility in tailoring the project to their needs. LANL selected three of the proposed tasks to be performed--Task 1- system modification and demonstration, Task 2-stainless steel mandrel trials, and Task 4-manufacturing study. Task 1 focused on converting the CVD system from a hot-wall to a cold-wall configuration and demonstrating the improved efficiency of the reactor type by depositing a 0.01-inch-thick nickel coating on a cylindrical substrate. Since stainless steel substrates were preferred because of their low α-emitter levels, Task 2 evaluated mandrel configurations which would allow removal of the nickel tube from the substrate. The manufacturing study was performed to develop strategies and system designs for manufacturing large quantities of the components needed for the Sudbury Nuetrino Observatory (SNO) program. Each of these tasks was successfully completed. During these efforts, BIRL successfully produced short lengths of 2-inch-diameter tubing and 6-inch-wide foil with levels of α-radiation emitting contaminants lower than either conventional nickel alloys or electroplated materials. We have produced both the tubing and foil using hot-substrate, cold-wall reactors and clearly demonstrated the advantages of higher precursor efficiency and deposition rate associated with this configuration. We also demonstrated a novel mandrel design which allowed easy removal of the nickel tubing and should dramatically simplify the production of 1.5-meter-long tubes in the production phase of the program

Evolution of the microstructure in nanocrystalline copper electrodeposits during room temperature storage

DEFF Research Database (Denmark)

Pantleon, Karen; Somers, Marcel A. J.

2007-01-01

The microstructure evolution in copper electrodeposits at room temperature (self-annealing) was investigated by means of X-ray diffraction analysis and simultaneous measurement of the electrical resistivity as a function of time. In-situ studies were started immediately after electrodeposition......, crystallographic texture changes by multiple twinning and a decrease of the electrical resistivity occurred as a function of time at room temperature. The kinetics of self-annealing is strongly affected by the layer thickness: the thinner the layer the slower is the microstructure evolution and self-annealing...

Fabrication of mesoporous cerium dioxide films by cathodic electrodeposition.

Science.gov (United States)

Kim, Young-Soo; Lee, Jin-Kyu; Ahn, Jae-Hoon; Park, Eun-Kyung; Kim, Gil-Pyo; Baeck, Sung-Hyeon

2007-11-01

Mesoporous cerium dioxide (Ceria, CeO2) thin films have been successfully electrodeposited onto ITO-coated glass substrates from an aqueous solution of cerium nitrate using CTAB (Cetyltrimethylammonium Bromide) as a templating agent. The synthesized films underwent detailed characterizations. The crystallinity of synthesized CeO2 film was confirmed by XRD analysis and HR-TEM analysis, and surface morphology was investigated by SEM analysis. The presence of mesoporosity in fabricated films was confirmed by TEM and small angle X-ray analysis. As-synthesized film was observed from XRD analysis and HR-TEM image to have well-crystallized structure of cubic phase CeO2. Transmission electron microscopy and small angle X-ray analysis revealed the presence of uniform mesoporosity with a well-ordered lamellar phase in the CeO2 films electrodeposited with CTAB templating.

Silver electrodeposition on nanostructured gold: from nanodots to nanoripples

International Nuclear Information System (INIS)

Claro, P C dos Santos; Fonticelli, M; BenItez, G; Azzaroni, O; Schilardi, P L; Luque, N B; Leiva, E; Salvarezza, R C

2006-01-01

Silver nanodots and nanoripples have been grown on nanocavity-patterned polycrystalline Au templates by controlled electrodeposition. The initial step is the growth of a first continuous Ag monolayer followed by preferential deposition at nanocavities. The Ag-coated nanocavities act as preferred sites for instantaneous nucleation and growth of the three-dimensional metallic centres. By controlling the amount of deposited Ag, dots of ∼50 nm average size and ∼4 nm average height can be grown with spatial and size distributions dictated by the template. The dots are in a metastable state. Further Ag deposition drives the dot surface structure to nanoripple formation. Results show that electrodeposition on nanopatterned electrodes can be used to prepare a high density of nanostructures with a narrow size distribution and spatial order

Efficient production of ultrapure manganese oxides via electrodeposition.

Science.gov (United States)

Cheney, Marcos A; Joo, Sang Woo; Banerjee, Arghya; Min, Bong-Ki

2012-08-01

A new process for the production of electrolytic amorphous nanomanganese oxides (EAMD) with uniform size and morphology is described. EAMD are produced for the first time by cathodic deposition from a basic aqueous solution of potassium permanganate at a constant temperature of 16°C. The synthesized materials are characterized by XRD, SEM, TEM, and HRTEM. The materials produced at 5.0 V at constant temperature are amorphous with homogeneous size and morphology with an average particle size around 20 nm, which appears to be much lesser than the previously reported anodic EAMD. A potentiostatic electrodeposition with much lesser deposition rate (with respect to previously reported anodic depositions) is considered to be the reason behind the very low and homogenous particle size distribution due to the lesser agglomeration of our as-synthesized nanoparticles. Copyright © 2012 Elsevier Inc. All rights reserved.

Nonequilibrium fluctuations in micro-MHD effects on electrodeposition

International Nuclear Information System (INIS)

Aogaki, Ryoichi; Morimoto, Ryoichi; Asanuma, Miki

2010-01-01

In copper electrodeposition under a magnetic field parallel to electrode surface, different roles of two kinds of nonequilibrium fluctuations for micro-magnetohydrodynamic (MHD) effects are discussed; symmetrical fluctuations are accompanied by the suppression of three dimensional (3D) nucleation by micro-MHD flows (the 1st micro-MHD effect), whereas asymmetrical fluctuations controlling 2D nucleation yield secondary nodules by larger micro-MHD flows (the 2nd micro-MHD effect). Though the 3D nucleation with symmetrical fluctuations is always suppressed by the micro-MHD flows, due to the change in the rate-determining step from electron transfer to mass transfer, the 2D nucleation with asymmetrical fluctuations newly turns unstable, generating larger micro-MHD flows. As a result, round semi-spherical deposits, i.e., secondary nodules are yielded. Using computer simulation, the mechanism of the 2nd micro-MHD effect is validated.

Prevalence of nickel allergy in Europe following the EU Nickel Directive - a review

DEFF Research Database (Denmark)

Ahlström, Malin G; Thyssen, Jacob P; Menné, Torkil

2017-01-01

.4% versus 19.8%) (p = 0.02), in female dermatitis patients aged ≤17 years (14.3% versus 29.2%) (p women: 20.2% versus 36.6%) (p men: 4.9% versus 6.6%) (p ..., and generally remained high, affecting 8-18% of the general population. A consistent pattern of decreasing prevalence of nickel allergy in some EU countries was observed, although the prevalence among young women remains high. Steps should be taken for better prevention of nickel allergy in EU countries.......Nickel contact allergy remains a problem in EU countries, despite the EU Nickel Directive. To study the prevalence of nickel allergy in EU countries following the implementation of the EU Nickel Directive, we performed a systematic search in PubMed for studies that examined the prevalence of nickel...

Microgravity effects on electrodeposition of metals and metal-cermet mixtures

Science.gov (United States)

Maybee, George W.; Riley, Clyde; Coble, H. Dwain

1987-01-01

An experimental system, designed to investigate the potential advantages of electrodeposition in microgravity, is being developed by the McDonnell Douglas Astronautics Company-Huntsville Division and the University of Alabama in Huntsville. It is intended to fly as an Orbiter payload when NASA resumes STS operations. The system will provide power, thermal conditioning, command and control for the production of electrodeposits; system performance data will be recorded for post-flight analysis. Plated metal surfaces will be created using simple electrolytic cells with pure metal electrodes immersed in aqueous electrolytic solutions. Crystalline structure and other properties will be analyzed to identify differences between samples produced in flight and those obtained from ground-based operations.

Impedance measurements of nanoporosity in electrodeposited ZnO films for DSSC

Energy Technology Data Exchange (ETDEWEB)

Dupuy, L.; Haller, S.; Rousset, J.; Donsanti, F.; Guillemoles, J.-F.; Lincot, D. [Institute of R and D on Photovoltaic Energy (IRDEP), UMR 7174 EDF-CNRS-Chimie Paristech, 6 quai Watier, 78400 Chatou (France); Decker, F. [Chemistry Department, ' ' Sapienza' ' Universita di Roma, 00185 Roma (Italy)

2010-05-15

Porous ZnO/dye hybrid films have been deposited by cathodic electrodeposition, and their active surface area after dye desorption was evaluated by impedance measurements with the semiconducting electrode polarized in accumulation. Surface area ratios have been deduced for a large number of films from imaginary part Z' vs. frequency measurements, having a constant rate over the frequency range from 0.5 Hz to > 50 Hz. The active surface increased by a factor of roughly 150 per every micron of film with respect to the area of a flat ZnO electrode: this linear relationship held from less than 1 {mu}m up to 9 {mu}m thick films. (author)

Morphological instability during steady electrodeposition at overlimiting currents

DEFF Research Database (Denmark)

Nielsen, Christoffer Peder; Bruus, Henrik

2015-01-01

We present a linear stability analysis of a planar metal electrode during steady electrodeposition. We extend the previous work of Sundstrom and Bark by accounting for the extended space-charge density, which develops at the cathode once the applied voltage exceeds a few thermal voltages...

Influence of the rate of filtration of a complexly alloyed nickel melt through a foam-ceramic filter on the sulfur impurity content in the metal

Science.gov (United States)

Sidorov, V. V.; Min, P. G.; Folomeikin, Yu. I.; Vadeev, V. E.

2015-06-01

The article discusses the possibility of additional refining of a complexly alloyed nickel melt from a sulfur impurity by decreasing the filtration rate during the passage of the melt through a foam-ceramic filter. The degree of sulfur removal from the melt is shown to depend on its content in the alloy and the melt filtration rate.

Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi2S4) nanoparticles hybrid anode for high performance lithium ion capacitor.

Science.gov (United States)

Jagadale, Ajay; Zhou, Xuan; Blaisdell, Douglas; Yang, Sen

2018-01-25

Lithium ion capacitors possess an ability to bridge the gap between lithium ion battery and supercapacitor. The main concern of fabricating lithium ion capacitors is poor rate capability and cyclic stability of the anode material which uses sluggish faradaic reactions to store an electric charge. Herein, we have fabricated high performance hybrid anode material based on carbon nanofibers (CNFs) and cobalt-nickel sulfide (CoNi 2 S 4 ) nanoparticles via simple electrospinning and electrodeposition methods. Porous and high conducting CNF@CoNi 2 S 4 electrode acts as an expressway network for electronic and ionic diffusion during charging-discharging processes. The effect of anode to cathode mass ratio on the performance has been studied by fabricating lithium ion capacitors with different mass ratios. The surface controlled contribution of CNF@CoNi 2 S 4 electrode was 73% which demonstrates its excellent rate capability. Lithium ion capacitor fabricated with CNF@CoNi 2 S 4 to AC mass ratio of 1:2.6 showed excellent energy density of 85.4 Wh kg -1 with the power density of 150 W kg -1 . Also, even at the high power density of 15 kW kg -1 , the cell provided the energy density of 35 Wh kg -1 . This work offers a new strategy for designing high-performance hybrid anode with the combination of simple and cost effective approaches.

[Comparison of fibroblastic cell compatibility of type I collagen-immobilized titanium between electrodeposition and immersion].

Science.gov (United States)

Kyuragi, Takeru

2014-03-01

Titanium is widely used for medical implants. While many techniques for surface modification have been studied for optimizing its biocompatibility with hard tissues, little work has been undertaken to explore ways of maximizing its biocompatibility with soft tissues. We investigated cell attachment to titanium surfaces modified with bovine Type I collagen immobilized by either electrodeposition or a conventional immersion technique. The apparent thickness and durability of the immobilized collagen layer were evaluated prior to incubation of the collagen-immobilized titanium surfaces with NIH/3T3 mouse embryonic fibroblasts. The initial cell attachment and expression of actin and vinculin were evaluated. We determined that the immobilized collagen layer was much thicker and more durable when placed using the electrodeposition technique than the immersion technique. Both protocols produced materials that promoted better cell attachment, growth and structural protein expression than titanium alone. However, electrodeposition was ultimately superior to immersion because it is quicker to perform and produces a more durable collagen coating. We conclude that electrodeposition is an effective technique for immobilizing type I collagen on titanium surfaces, thus improving their cytocompatibility with fibroblasts.

Properties and electrochemical behaviors of AuPt alloys prepared by direct-current electrodeposition for lithium air batteries

International Nuclear Information System (INIS)

Zhang, Jinqiu; Li, Da; Zhu, Yiming; Chen, Miaomiao; An, Maozhong; Yang, Peixia; Wang, Peng

2015-01-01

AuPt catalyst has a prospective application in a lithium air battery because of its bi-function on catalyzing Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER). Electrodeposition is an in-situ convenient technology for catalyst preparation without chemical residue. In an acid electrolyte, AuPt alloy catalysts were electrodeposited on carbon paper. The effect of main salt concentration, electrodeposition time and current density were studied by deposit micromorphology observation, structure analyses and composition testing. Catalytic abilities of AuPt alloys were measured by cyclic voltammetry (CV) in an ionic liquid of EMI-TFSI/Li-TFSI [1- Ethyl - 3- methylimidazolium–bis (trifluoromethanesulphonyl) imide/lithium–bis (trifluoromethanesulphonyl) imide]. The electrochemical behaviors of Au, Pt and AuPt deposits were also measured. An optimized direct-current electrodeposition process of getting high active AuPt catalyst is concluded, which is an aqueous solution containing 6.7∼10 mmol · L −1 HAuCl 4 , 10∼13.3 mmol · L −1 H 2 PtCl 6 and 0.5 mol · L −1 H 2 SO 4 as the electrolyte, current density of 20mA · cm −2 and electrodeposition time of 8∼34 s. The co-deposition of AuPt alloy is an irregular co-deposition controlled by diffusion, while gold atoms enter the platinum’s crystal lattice in the structure of AuPt alloy. The increase of the concentration of H 2 PtCl 6 in the electrolyte, the extension of the electrodeposition time or the raise of the current density can improve the content of Pt in the deposit. The clusters’ diameters of AuPt catalysts decrease to 150∼250 nm by adjusting current densities during electrodeposition

Whisker and Hillock formation on Sn, Sn-Cu and Sn-Pb electrodeposits

International Nuclear Information System (INIS)

Boettinger, W.J.; Johnson, C.E.; Bendersky, L.A.; Moon, K.-W.; Williams, M.E.; Stafford, G.R.

2005-01-01

High purity bright Sn, Sn-Cu and Sn-Pb layers, 3, 7 and 16 μm thick were electrodeposited on phosphor bronze cantilever beams in a rotating disk apparatus. Beam deflection measurements within 15 min of plating proved that all electrodeposits had in-plane compressive stress. In several days, the surfaces of the Sn-Cu deposits, which have the highest compressive stress, develop 50 μm contorted hillocks and 200 μm whiskers, pure Sn deposits develop 20 μm compact conical hillocks, and Sn-Pb deposits, which have the lowest compressive stress, remain unchanged. The differences between the initial compressive stresses for each alloy and pure Sn is due to the rapid precipitation of Cu 6 Sn 5 or Pb particles, respectively, within supersaturated Sn grains produced by electrodeposition. Over longer time, analysis of beam deflection measurements indicates that the compressive stress is augmented by the formation of Cu 6 Sn 5 on the bronze/Sn interface, while creep of the electrodeposit tends to decrease the compressive stress. Uniform creep occurs for Sn-Pb because it has an equi-axed grain structure. Localized creep in the form of hillocks and whiskers occurs for Sn and Sn-Cu because both have columnar structures. Compact hillocks form for the Sn deposits because the columnar grain boundaries are mobile. Contorted hillocks and whiskers form for the Sn-Cu deposits because the columnar grain boundary motion is impeded

Cr-Ni ALLOY ELECTRODEPOSITION AND COMPARISON WITH CONVENTIONAL PURE Cr COATING TECHNIQUE

Directory of Open Access Journals (Sweden)

M. Moniruzzaman

2012-12-01

Full Text Available Cr coating is widely used as the outer surface of precision parts due to its attractive appearance and superior corrosion resistance properties. It is obtained by electrodeposition via a conventional bath with hexavalent Cr ions. This manufacturing technique has many drawbacks, such as very low efficiency and high operating temperature and it is hazardous to health. In this work, we studied a Cr-Ni alloy deposition technique and compared the alloy coating properties to those with conventional Cr coating. Sequential two-step alloy electrodeposition was also compared. We took varying concentrations of Cr, Ni and complexing agents for the electrodeposition of Cr-Ni alloy and sequential Cr-Ni alloy coating on mild steel. Operating parameters, i.e. current density and temperature, were varied to examine their effects on the coating properties. The coatings thus obtained were characterized by visual observation, corrosion test, microhardness measurement, morphology and chemical analysis. The Cr-Ni alloy coating was found to be more corrosion resistant in 5% NaCl solution and harder than the pure Cr coating obtained by conventional electrodeposition. Toxic gas was produced in a much lower extent in the alloy coating than the conventional Cr coating technique. Again, the two-step Cr-Ni alloy coating was found better in terms of corrosion resistance as well as hardness compared to the Cr-Ni alloy coating. The process was also found to be much more environmentally friendly.

Studies on electrodeposition and characterization of the Ni–W–Fe alloys coatings

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Aldrighi Luiz M.; Costa, Josiane D.; Sousa, Mikarla B. de; Alves, José Jailson N. [Department of Chemical Engineering, Federal University of Campina Grande, Av. Aprígio Veloso, 882, 58429-970 Campina Grande (Brazil); Campos, Ana Regina N.; Santana, Renato Alexandre C. [Department of Education, Federal University of Campina Grande, R. Olho da Água da Bica, S. N., 58175-000 Cuité-Pb (Brazil); Prasad, Shiva, E-mail: prasad@deq.ufcg.edu.br [Department of Education, Federal University of Campina Grande, R. Olho da Água da Bica, S. N., 58175-000 Cuité-Pb (Brazil)

2015-01-15

Highlights: • Ni–W–Fe alloy resistant to corrosion has been obtained by electrodeposition. • Optimal temperature and current density for Ni–W–Fe alloy electrodeposition has been found. • Experimental design has been used as optimization tool. • Amorphous Ni–W–Fe alloy has been obtained. - Abstract: Corrosion has been responsible for industrial maintenance cost as well as for industrial accidents. A key to prevent corrosion is to develop advanced materials with highly anti-corrosive properties. The electrodeposition has been one of the most important techniques for obtaining these materials. The objective of this work is to develop and optimize the parameters to obtain a new Ni–W–Fe alloy with high resistance to corrosion. A factorial design 2{sup 2} with 2 center points was used to find the optimal current density and bath temperature for Ni–W–Fe electrodeposition. The influence of such variables on the cathodic current efficiency and polarization resistance were obtained. The alloys obtained with the highest current density (125 mA/cm{sup 2}) and the highest bath temperature (70 °C) had the best anticorrosive properties, which are superior to anticorrosive properties of Ni–W–Fe available in the literature. The obtained alloys had the highest tungsten content compared with other alloys studied of about 46 wt.%. The highest cathodic current efficiency was 34% for the alloy with a chemical composition of 3 wt.% Fe, 29 wt.% W and 68 wt.% Ni.

Contaminated nickel scrap processing