Using a colloidal suspension, electrochemically active tungsten oxide thin films (150 nm) have been prepared via ultrasonic spray deposition using two different current collectors, namely TiN and Pt.
TürkiyeCusil TM is a eutectic brazing alloy of 72% silver, 28% copper composition; used to join different materials. The large difference between the standard reduction potentials of silver (0.799V) and copper (0.337V) makes their electrochemical codeposition difficult. A complex ion bath containing KAg(CN)2, CuCN and KCN was used to bring the reduction potentials closer together. The effect of electrolyte concentration on composition and microstructure of electrodeposited Ag-Cu films was investigated at 25 o C. A current density of 2 mA/cm 2 was used to codeposit copper and silver based on results of voltammetric studies. It was found that increasing KCN and KAg(CN)2 and decreasing CuCN concentrations increased Ag contents of deposits. Surface morphology was spherical grained in general. Increasing Ag content of the deposits resulted in finer grained structures, but deposits containing higher Ag concentrations were found to develop dendritic structures especially after the initial deposition of the Ag-Cu alloy coating on the surface.
(LTO) is considered as a promising anode material for lithium ion batteries due to its high stability and its inherent safety. Since LTO is typically synthesized at high temperatures, a study of combustion synthesis of LTO is presented, wherein effects of oxidizer amount in the precursor and atmosphere during thermal decomposition are investigated. Combustion synthesis implies heating a precursor to a relatively low process temperature, after which the system generates the necessary energy for complete conversion and crystallization to the desired oxide. Hereto, the precursor and thermally treated powders were characterized by thermogravimetric analysis (TGA) coupled with differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), cyclic voltammetry (CV) and galvanostatic cycling. The study shows that the combustion process allows the synthesis of LTO at process temperatures as low as 300 C, compared to around 800 C for solid state reactions and sol-gel routes. The product consists of crystalline LTO with minor impurities. The product was used as an electrode material in a lithium battery coin cell and demonstrated a high stability and a capacity of 164 mA h g À1 at 0.1C and 132 mA h g À1 at 2C. This paper shows that combustion synthesis can considerably lower the temperature required for the synthesis of ceramic materials, after careful optimization of the precursor, since the mechanism of thermal degradation is complex and dependent on a large number of parameters.
The eutectic Ag-Cu composition is a common brazing alloy. A complex ion bath containing KAg(CN)2, CuCN, KCN and K4P2O7 was used to codeposit Ag and Cu. The effects of KAg(CN)2, KCN and K4P2O7 concentrations on the composition and morphology of electrodeposited Ag-Cu films was investigated in this study. A constant CuCN concentration of 0.1 M was used. The increase in KCN and KAg(CN)2 concentrations caused major increases in Ag contents, but increase in K4P2O7 concentration caused a minor decrease in Ag content of the film. The deposits were found to be globular clusters when high KAg(CN)2 concentrations were used. Finer microstructures and higher Ag contents were observed in deposits produced in electrolytes containing higher KCN concentrations.
One of the common brazing alloys, CusilTM, has eutectic composition of 72 % silver and 28 % copper. The electrochemical codeposition of Ag and Cu is difficult due to the large difference between the standard reduction potentials of silver (0.799 V) and copper (0.337 V). A complex ion bath containing KAg(CN)2, CuCN, KCN and K4P2O7 was used to overcome this difficulty and bring the reduction potentials closer to each other. The effects of KAg(CN)2, KCN and K4P2O7 concentrations on the composition and microstructure of electrodeposited Ag-Cu films was investigated in this study. The effect of K4P2O7 addition to the electrolyte was examined in a set of experiments by employing a three-level full-factorial statistical design. The concentrations of bath ingredients: KCN, KAg(CN)2 and K4P2O7 were the factors that were investigated. The levels of the design were chosen at the minimum, mean and maximum amounts of the three factors. Therefore, (33) 27 experiments were designed to investigate the effects of changes in bath concentration on composition and morphology of deposits. All the other plating parameters were fixed during the experiments. The increase in K4P2O7 concentration caused a minor decrease in Ag content of the film where the increase in KCN and KAg(CN)2 concentrations caused major increases in Ag contents. The microstructures of deposits were found to be globular clusters when high KAg(CN)2 concentrations were used. K4P2O7 addition to the electrolyte suppressed cluster formation and produced more compact microstructures. Increasing the KCN concentration resulted in deposits having finer microstructures and higher Ag contents.
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