Papers by Keyword: Complexing Agent

Abstract: This research deals with the interest in production of Cu-Sn-Zn ternary alloy coating via electroplating on carbon substrate by using less hazardous electrolyte. A detailed study was made on the effect of different concentration of reducing and complexing agents. The surface morphology and phase structure of the deposited layers were examined by scanning electron microscope (SEM) equipped with energy dispersive x-ray spectroscopy (EDS), respectively. The results confirmed that the layers of Cu-Sn-Zn was obtained with this less hazardous electrolyte.

Abstract: Complexing agent in the electroless nickel coating (Ni-P) solution plays an important role to maintain the coating deposition rate during the coating process. This paper studies the effect of two complexing agent; sodium citrate and sodium acetate in Ni-P coating. Ni-P coating was prepared in bath containing: NiSO4·6H2O, NaPO2H2·H2O, C2H5NO2, and Pb (NO3)2. Ni-P coating was coated on polished Cu substrate. Morphology, thickness and surface roughness of Ni-P coating were characterized using scanning electron microscope (SEM)/electron dispersive x-ray (EDX), optical microscope (OM), and atomic force microscopy (AFM). The result showed that sodium acetate have higher deposition rate up to 12 μm/h, whereas sodium citrate provided better surface morphology with lower surface roughness.

Abstract: Ordered magnetic Fe_xCo_1-x alloy nanowires were synthesized in a porous alumina template by electrodeposition. The structural and magnetic properties of the as-deposited nanowires were investigated by SEM, TEM, XRD, EDS and VSM, respectively. The influence of the complexing agent on the stoichiometric properties is discussed, and the results indicate that the modulation of buffer and complexing agent has great influence on the electrodeposition process.

Abstract: ZnS films have been deposited on glass substrates by chemical bath deposition (CBD). The optical and structural properties were analyzed by UV-VIS spectrophotometer and X-ray diffraction (XRD). The results showed that the prepared thin films from the solution using N₂H₄ as second complexing agent were thicker than those from the solution without adding N₂H₄ in; this is due to using second complexing agent of N₂H₄, the deposition mechanisms change which is conductive to heterogeneous deposition. When using N₂H₄ as second complexing agent, the crystallinity of ZnS thin films improved with a significant peak at 2θ=28.96°which can be assigned to the (111) reflection of the sphalerite structure. The transmittances of the prepared films from the solution adding N₂H₄ in as second complexing agent were over 85%, compared to those from the solution without N₂H₄ (over 95%). The band gaps of the ZnS films from the solution using N₂H₄ as second complexing agent were larger (about 4.0eV) than that from those from the solution without N₂H₄ (about 3.98eV), which indicated that the prepared ZnS films from the solution adding N₂H₄ in as second complexing agent were better used as buffer layer of solar cells with adequate optical properties. In short, using N₂H₄ as second complexing agent, can greatly improve the optical and structural properties of the ZnS thin films.

Abstract: Abstract. Electrodeposition of ZnS thin film is affected by many factors. The effects of experimental conditions and concentrations of complexing agents on the electrochemical properties of plating solution were investigated. Electrochemical workstation was used to test cyclic voltammetry curves in different situations. According to the oxidation and reduction peaks of the curves, the experimental results showed that the effect of complexing agent was the best, while the ammonia was worst. With the increase of concentration of sodium citrate, reduction peak shifted to the negative part, in the meanwhile plating solution with 30 mmol/L of sodium citrate was the best condition for electrodeposition of ZnS thin film.

Abstract: Zn-Ni alloy coatings were electrodeposited on low carbon steel substrate using a cyanide-free alkaline bath containing tetraethylenepentamine (TEPA) and triethanolamine (TEA) as complexing agents for Ni²⁺ cations. Effect of TEA/Ni²⁺ molar ratio on electrodeposition behavior, micromophology, Ni content and corrosion resistance of coatings were studied by means of SEM/EDS, polarization curve and electrochemical impedance spectroscopy (EIS), respectively. It was found that the deposition potential and elecctrochemical impedance of the cathode sample during the electrodeposition was influenced by the TEA/Ni²⁺ molar ratio (TN_mr) in the bath. The deposition potential shifts negatively and the impedance rises with increasing TN_mr up to 2. The nickel content in Zn-Ni deposit was varied in a range from 16.81 to 19.04 wt.%. The dependence of cathodic current efficiency and depositing velocity of the coating on TN_mr of plating bath were also determined. A fine-grained and smooth-faced coating was obtained at TN_mr =2, which exhibited the highest corrosion resistance in 3.5% NaCl environment.

Abstract: In this paper, the method of electroless deposition of nickel-phosphorous composite coating on the sample surface is employed. The effect of the complexing agent ratio on the surface morphology and phase composition of nickel-phosphorus coating when the main salt and reducing agent concentration unchanged has been studied. The influence of heat treatment on properties and microstructure of coatings are also investigated. Experimental results show that in the case of salt and reducing agent concentration unchanged, complexing agent concentration has strong effect on the morphology of the coatings and the crystal structure of the composite coating. During heat treatment, the morphology of the composite coating changed significantly, and the hardness was improved a certain degree for all the samples, which is related to the precipitation of Ni₃P.

Abstract: The gangue mineral surface inevitably enriches some copper ions, nickel ions and other metal ions when copper-nickel sulfide ore is ground and in the flotation process. These ions can activate the gangue minerals so as to influence the selective separation of valuable minerals and gangue minerals. This paper, based on the ore property, found that complexing agent LXA could make nickel grade increase to 7.88% from 6.32%, but the recovery rate reduced by 15.61%; complexing agent LXH1 could make nickel grade and recovery rate increase by 0.6% and 1.3% respectively by comparing the flotation effect in the presence of complexing agent EDTA, LXH1, sodium thiosulfate and LXA respectively.

Abstract: In high-tech processing even smallest concentrations of metal ions in process media are of the utmost significance because they cause expensive production failures. Currently, cost-intensive equipment, special trained staff and time consuming analyses are necessary to detect these contaminations in order to avoid failures. The Centers of Excellence Nanochem and Sensorics at the University of Applied Sciences Regensburg (owner of patent PCT/EP2010/064833) and their industrial partner Micro-Epsilon GmbH are developing a new miniaturized measurement device which allows cost-effective real-time analysis of fluidic media for the first time. The system is fully automated and can be directly connected to wet-etch benches. Hence it allows continuous real-time surveillance of metal contaminations in the ppb-range through absorption spectroscopy in process media. For this purpose a very small sample amount of the process medium and a specific complexing agent are mixed together. This leads to an increase in the molar extinction coefficients and though even smallest contaminations become visible. The main parts of our development are the simulation of the different system components, their production and chemical analyses with the evaluation model.

Abstract: The electrodeposited CuInSe2 films were investigated in this paper. The deposition parameters of various solution concentrations, applied potential, pH value and complexing agent were examined to characterize film quality. The electrolyte solution was formed by mixing an appropriate proportion of copper sulfate, indium sulfate and selenium dioxide. Sodium citrate was used as complexing agent. Citric and sulfuric acids were used for adjusting electrolyte pH value. The experimental results revealed that the deposited and annealed CIS films have an atomic ratio of [Cu]：[In]：[Se] = 26.94：26.74：46.31. It is near to the stoichiometry of an atomic ratio ([Cu]：[In]：[Se] = 1：1：2). Unfortunately, this film has a poor adhesion problem. In order to overcome the adhesion problem, the triethanolamine and sodium dodecyl sulfate are used as complexing agents and wetting agents, respectively. A good adhesion was obtained. However, these additives result in a shortcoming of insufficient indium content in the formation film.