Papers by Keyword: Electrochemical Deposition

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Authors: Q. Humayun, U. Hashim
Abstract: Fabrication techniques for Metal-molecule-metal junction electrodes suitable to study electron tunneling through metal junctions are reviewed. The applications of current technologies such as mechanical break junction, electromigration, shadow mask lithography, focused ion beam deposition, chemical and electrochemical plating, electron-beam lithography, in fabricating vacant junction electrodes are briefly described. For biomolecular sensing applications, the size of the junction electrodes must be small enough to allow the biomolecule inserted into the junction space to connect both leads to keep the molecules in a relaxed and undistorted state. A significant advantage of using Metal-molecule-metal junction electrodes devices is that the junction can be characterized with and without the molecule in place. Any electrical artifacts introduced by the electrode fabrication process are more easily deconvoluted from the intrinsic properties of the molecule.
867
Authors: Xu Yang, Fu Sheng Pan, Ding Fei Zhang
Abstract: With the aim of evaluating corrosion inhibition for various inhibitors, a new qualitative method for corrosion inhibition effect test for magnesium and magnesium alloys was developed. The change of polarization current density of AZ61 magnesium alloy in electrochemical polarization experiments in alkali aqueous solution with 5mmol/L sodium dodecylsulphate(SDS), phytic acid(PA), ethylenediamine tetraacetic acid(EDTA), p-nitro-benzene-azo-resorcinol(PNBAR), acidum tannicum(AT) or stearic acid(SA) were tested. The SEM-EDS techniques and deposition experiment method were used for further confirmation of the corrosion inhibition. The results showed that those organic compounds which could form the inhibitor-magnesium precipitation in aqueous solution could be used as corrosion inhibitors for magnesium alloys to inhibit the increase of polarization current density as well as the dissolution and oxidation of magnesium alloys effectively.
920
Authors: Hong Min Kan, Ning Zhang, Xiao Yang Wang
Abstract: To develop hydrogen storage materials is the key to hydrogen storage. Magnesium theoretically stores 7.6 wt.% hydrogen, although it requires heating to above 300°C in order to release hydrogen. This limits its use for mobile application. However, due to its low price and abundance magnesium should still be considered as a potential candidate for hydrogen storage e.g. in stationary applications. Recent advances in Al-Mg alloy powders for hydrogen storage is presented in this paper. The main focus is on preparation of Mg-Al alloy and hydrogen storage properties of Mg-Al alloys. It is pointed the microstructure and components of Nano Mg-Al alloy have a great impact on the hydrogen-storage properties. Electrochemical deposition will be used to prepare the Nano Mg-Al alloy. Research will focuse on the nucleation mechanism and the influence of microstructure and components of the alloy on the hydrogen-storage properties.
497
Authors: Devi Shantini Chandrasakaran, Irwana Nainggolan, Tulus Ikhsan, Mohd Nazree Derman
Abstract: Ammonia classified as one of the hazardous chemical to environment and human. Therefore, monitoring the ammonia in air is vital. Chitosan film was selected as a sensing material for ammonia detection in this study. Chitosan powder was dissolved in 2% of acetic acid to form chitosan solution gel. It was subsequently deposited on patterned electrode by using electrochemical deposition technique. The response of the chitosan sensor towards ammonia was tested via electrical testing by exposing different ammonia concentration ranging from 20 ppm, 100 ppm, 200 ppm, and 300 ppm using air exposure technique. The response of the chitosan sensor towards ammonia was recorded as output voltage. Sensor properties which include sensitivity, stability, recovery, and repeatability were studied. The electrical result showed that the response of chitosan sensor increases as the ammonia concentration increases. All the sensing properties were achieved. Finally, the structure characterization of the chitosan was studied using Fourier Transform Infrared Spectroscopy (FTIR). The appearance of N-H and O-H groups in FTIR spectrum of chitosan film provides evidence that the domain functional group exist in chitosan after it was processed into film.
429
Authors: Jing Jing Gao, Bo Li, Zhen Dong Liu, Xing Jian Jiao, Ji Zhou, Hong Lin, Long Tu Li
Abstract: Because of the features of photonic localization in photonic bandgap(PBG), the photonic crystals can be coupled to DSSC to increase the conversion efficiency. In this paper, through exploring the preparation of large inverse opal structure of ZnO, we attempt to apply the photonic crystals to the Dye-Sensitized Solar Cells (DSSC) to improve its efficiency. The colloidal crystal template is prepared by self-assembled on FTO substrates, and three-dimensional ZnO inverse opal is synthesized via an electrochemical deposition method in zinc nitrate solution. Then we study the inflations of its surface morphology and photonic bandgap on the solar cell’s photoelectric conversion efficiency.
1609
Authors: Mu Qin Li, Li Jie Qu, Chen Ma, Shi Qin Yang
Abstract: This study examined the bioactive and stability of calcium phosphate- polypyrrole(ppy) composite coatings on titanium alloys by electrochemically deposition in simulated body fluid (SBF). Change of coatings mass and SBF pH during coatings soaked in SBF indicated that ppy reduces the decomposition of coatings. The surface morphology of coatings characterized by SEM showed that the stability of composition coating was superior to that of single coating. XRD indicated that ppy induces CO3 2- enter calcium phosphate coating, which showed that the composite coatings possess better bioactive. Thus, this electrochemical deposition provides an effective method of ppy incorporation at physiological temperature, which can offer excellent bioactive and stability of coatings, with a potential for sustained release of therapeutic agents as required for metallic implant fixation.
1198
Authors: Lidia Benea, Iulian Bounegru, Alexandru Chiriac
Abstract: Novel hybrid Co/UHMWPE biocoatings were obtained by electrochemical deposition of cobalt from a cobalt sulfate plating bath with ultra high molecular weight polyethylene (UHMWPE - particle size of 10 μm) as dispersed particles in order to provide possible biomedical coatings applications. The surface morphology and topography, roughness and chemical composition were investigated, as a function of UHMWPE particles concentration in the plating bath by scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray analysis (EDX). Electrochemical corrosion resistance investigations were carried out in simulating body fluid solution (SBF), using electrochemical impedance spectroscopy (EIS) method at different exposure times. The results proved a good corrosion resistance of the obtained hybrid Co/UHMWPE coatings.
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Authors: Ya Jing Yan, Yong Huang, Qiong Qiong Ding, Xiao Feng Pang
Abstract: The present paper reports a novel solution to develop a calcium phosphates (CaPs) coating with an anodic nanotubular TiO2 layer on titanium screw by electrochemical disposition (ECD). The elemental composition of coatings was examined by energy dispersive spectroscopy (EDS), the surface mopholoy was characterized with scanning electron microscopy (SEM), and the functional groups and crystalline phase were analyzed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Furthermore, the bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. The results showed that a nanotubular TiO2 layer was established which has about 100 mm diameter and the calcium phosphate coatings have higher bioactivity and porosity compared with uncoated titanium screws, which make the coating more conductive to cell adhesion. Using alkaline treatment, the calcium phosphate coating could transform into hydroxyapatite (HAp), making the coating closer to the biological complement. This provides a valuable tool for biomedical applications.
251
Authors: Qiong Zhou, Xiao Mei Su, Hong Zhang, Yong Ji Weng
Abstract: Polyaniline (Pani) on graphite electrode was synthesized electrochemically under galvanostatic condition at current density of 2.0 mA/cm2 from aqueous solution of 1.0 mol/L HCl and 0.25 mol/L aniline monomer. The Electrochemical Impedance Spectroscopy investigation of Pani was carried out at different stages of polymers oxidation. In the potential range 0.2V~0.7 V vs SCE, with the increase of test potential the membrane resistance decreased rapidly, and Faraday process at the polymer/solution interface weakened. When the test potential in range of -0.8V~0.2V or 0.7V~0.8V, the film has a higher membrane resistance, and lower ionic charge transfer resistance, which indicated that the ion exchange for the charge compensation at the polymer/electrolyte interface is much easier. And anticorrosion properties of Pani coating of different oxidations was investigated by salt spray test. The final visual observations of the tested coatings are in agree with the results of electrochemical impedance spectroscopy.
1124
Authors: Devi Shantini Chandrasakaran, Irwana Nainggolan, Nazree Derman, Tulus Ikhsan
Abstract: Chloroform classified as one of the hazardous chemical to human. Therefore, monitoring the chloroform concentration in air is vital. In this study, chitosan powder was dissolved in 2% of acetic acid to form chitosan solution gel. It was subsequently deposited on printed circuit board (PCB) by using electrochemical deposition technique. The response of the chitosan sensor towards chloroform was tested via electrical testing by exposing different chloroform concentration ranging from 10 ppm, 20 ppm, 30 ppm, 40 ppm, and 50 ppm using air exposure technique. The response of the chitosan sensor towards chloroform was recorded as output voltage. Sensing properties of the chitosan sensor which include sensitivity, stability, recovery, and repeatability were studied. The electrical result showed that output voltage increases as the concentration of chloroform increases. All the sensing properties were achieved. The structure characterization of the chitosan was studied using Fourier Transform Infrared Spectroscopy (FTIR). The appearance of N-H and O-H groups in FTIR spectrum of chitosan film provides evidence that the domain functional group exist in chitosan after it was processed into film.
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