Showing 8 results for Copper
S. Vahabzadeh, M. A. Golozar, F. Ashrafizadeh and A. Ghasemi,
Volume 27, Issue 2 (1-2009)
Abstract
N. Sadeghi , E. Keshavarz Alamdari,
Volume 34, Issue 2 (7-2015)
Abstract
In the present study, the copper anode slime was leached in chloride media. Then, pregnant leach solution (PLS) was purified using solvent extraction method and Octanol-kerosene solution. HAuCl4.2L was determined as the extracted macromolecule, and separation of impurities, such as copper, iron and selenium was done in the presence of gold. McCabe-Thiele diagram of Au–HCl (3 M)– Octanol (40% v/v) in O/A=3/4 showed that Au concentration in aqueous phase decreased from the initial value of 200 to 7 mg/L, after 5 stages. Ammonia solution was proposed as the stripper and McCabe-Thiele diagram was presented to obtain the number of gold stripping steps by ammonia solution
F. Haghdoost, V. Mottaghitalab,
Volume 34, Issue 2 (7-2015)
Abstract
In the last decade, a significant progress has been made in the wearable medical devices. Scientists are extensively involved in the design of the flexible instruments equipped with garments to fulfill the daily needs and requirements. The fulfillment of this demand particularly needs a conductive fabric substrate with a high level of homogeneity, and the lowest barrier against electrical current. In this study, textile based ECG electrode was prepared by screen printing of activator followed by electroless plating of copper particles. The data acquisition showed the best outcome with pH=8.5 and the plating temperature
of 70 ˚C. The electrical resistance showed a range around 0.08 Ω/sq, which sounds quite proper for ECG signal acquisition since the potential difference according to heart activity on skin surface is in milivolt range. We tested the cardiac signal with a reference electrode of Electroshock monitoring system and the results revealed a very high quality receiving signal. Employing of these types of sensors in textile surface due to their flexibility can bring the users more freedom of action.
M. Asadrokht, A. R. Zakeri,
Volume 36, Issue 1 (6-2017)
Abstract
Despite a great thermodynamic driving force, copper cementation by aluminum from sulfate solutions involves a relatively slow kinetics due to the presence of the passive oxide film on the surface of aluminum. The previous studies have confirmed the positive effect of the presence of small amounts of chloride ion on reducing the scale of this problem. In this paper, the effect of concurrent ball milling on the kinetics of this process has been investigated. The cementation experiments were carried out in a polyamide jar with alumina balls inside by planetary ball milling. The studied parameters were ball number (0, 4), temperature (25-55 °C) and time (0-240 s). All experiments were conducted at constant condition of [Cu2+] = 6 g/L, [Cl−] = 75 mg/L, rotation speed of 160 rpm, average aluminum particle size of 279 µm and [H+] = 1.94×10-3. The results showed that concurrent ball milling reduces the induction period of the cementation process to less than 120 s. The apparent rate constant of cementation showed the positive influence of simultaneous milling on the kinetics of the studied cementation process. Moreover, activation energies of the induction and main periods were calculated to be respectively 86 and 26 kJ.mol-1, indicating the shift of the reaction mechanism from chemical control to mass transfer control.
D. Haghshenas, A. Amirjani,
Volume 36, Issue 4 (3-2018)
Abstract
In this study, null and one-dimensional nanoparticles and nanostructures of Ag and Ag-Cu were synthesized using polyol method. In order to prepare different nanostructures with the same synthesis route, thermodynamics and kinetic conditions of the system were manipulated. In the thermodynamics approach, the nanostructures with the minimum surface energy were obtained as the final product, while in kinetic approach, the nanostructures with the lower activation energy were formed. By using these appraoches, Ag and Ag-Cu spherical and cubical nanostructures were produced in the size range of 90-100 nm. Also, by manipulating the kinetic conditions of the system, silver nanowires with the diameters in the range of 100-200 nm and the length of several microns were obtained successfully. The effect of Cu ions (Cu2+) on aspect ratio of the synthesized silver nanowires by polyol method was evaluated.
F. Mansouri, M. Mehran,
Volume 39, Issue 1 (5-2020)
Abstract
In this paper, synthesis of inverted nano-pyramids on a single crystal silicon surface through a simple and cost-effective wet chemical method is surveyed. These structures were synthesized by MACE process using Cu as the assisted metal in the solution of copper nitrate, hydrogen peroxide and hydrofluoric acid for different etching times. FE-SEM images of the samples show that time is an important factor in the formation of silicon inverted nano-pyramids and by extending synthesis time the structures gradually fade. After synthesis, some samples were etched in KOH 2% and IPA 6% for one minute which resulted in formation of nano-pyramids besides inverted nano-pyramids on the silicon surface. Formation of these combinational structures affected the self-cleaning behavior of the silicon surface. X-ray diffraction (XRD) was utilized for studying the crystalline characteristics of the synthesized structures. Moreover, the self-cleaning behavior of them was studied using the contact angle goniometer. The results showed that the inverted nano-pyramids improve the hydrophilic behavior of the silicon surface while post-synthesized etching improves the hydrophobic behavior of the surface. These textures improve the performance of solar cells due to their self-cleaning and light adsorption properties
S. Masoomi Ganjgah , M. Abbasi,
Volume 39, Issue 4 (2-2021)
Abstract
This study aims at investigating changes in microstructure and strength of W alloy and Cu bimetals with varying spark plasma sintering (SPS) temperature and percentage of copper in W-Cu-Ni alloy. After SPS of W (12 wt%)-Cu (14 wt%)-Ni (3 wt%) alloy powder into consolidated discs at 1350 ° C, they were spark plasma sintered to copper discs at various temperatures. Assessment of the interface microstructure and shear strength was performed by field emission scanning electron microscpe (FESEM) and shear strength test, respectively. Results indicated SPS is successful in forming a perfect metallic bond with monolithic interface and high shear strength of about 45 MPa in Cu/W-12Cu-3Ni bimetal that is extra high quality and not reported in previous investigations.
R. Bagheri, F. Karimzadeh, A. Kermanpur , M. Kharaziha,
Volume 40, Issue 2 (9-2021)
Abstract
A new method has been presented for the synthesis of copper (Cu)/copper oxide (CuO)-nanoparticles (NPs), based on the process of corrosion and oxidation of Cu-NPs on the surface of the gold electrode by nitric acid. Cu-NPs were deposited on the surface using potentiometric method. The high concentration of Cu-NPs was estimated by Differential Pulse Voltammetry (DPV). The process of growth and distribution of CuO-NPs on the surface of Cu-NPs using structural analysis of Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) showed that nitrate was well absorbed and a sharp hydroxyl peak appeared and a phase of CuO NPs formed on the electrode surface. The surface morphology indicated that the average size reduced from about 150 nm to 50 nm in the presence of nitrate. This can be due to the oxidation of Cu nanoparticles on the surface and reduction of particle size compared to the absence of nitric acid. This simple and low-cost method can be used as a surface modification of antibacterial and active catalyst electrodes.
