Showing 7 results for Cyclic
Alah Karam S.r., Alah Karam S.r.,
Volume 1, Issue 1 (3-2004)
Abstract
In this paper redox reaction processes and phase, formation on ternary Pb-2Sn-0.08Ca alloy utilized as insoluble lead anodes in copper electro winning cells, were investigated in 2M H__2SO__4 electrolytes, using cyclic voltammetry technique (CVA). A potential range between - 1.3V to 2.6V was chosen at various scan rates in order to study the anodic behavior and phase composition of the oxide layers on Pb-2Sn-0.08Ca alloy. Potential measurements were carried out with respect to a standard calomel electrode (SCE). The surface examination and phase composition of the lead alloy were determined by electron microscopy analysis (SEM) and x-ray diffraction technique, after- exposure to the cyclic voltammetry tests. The results indicated that the protective oxide layer (Pb0__2) formed at a much slower rate when exposed to 2M H__2SO__4 solutions, whilst its degradation due to a reduction in the applied potential occurred at a much faster rate. Hence, Pb0__2 did not remain stable, when the externally applied potential dropped below 1.SV and as a result, pitting initiated sporadically on the surface of the electrode.
C. Dehghanian, Y. Mirabolfathi Nejad,
Volume 5, Issue 1 (3-2008)
Abstract
Abstract: Despite having a number of advantages, reinforced concrete can suffer rebar corrosion
in high–chloride media, resulting in failure of reinforced concrete structures. In this research the
corrosion inhibition capability of the mixture of calcium and ammonium nitrate of steel rebar
corrosion was investigated in the simulated concrete pore solution. Cyclic polarization and
Electrochemical Impedance Spectroscopy (EIS) techniques were applied on steel concrete pore
solution containing 2 weight percent sodium chloride (NaCl). Results show that such mixtures had
higher inhibition efficiency than calcium nitrate alone. The optimum concentration of the inhibitor
mixture was determined to be 45 mgr/lit.
M. Nusheh*, H. Yoozbashizadeh,
Volume 7, Issue 2 (6-2010)
Abstract
Abstract:
the competition between the precipitation of cobalt ions and evolution of hydrogen gas on the cathode surface during
the reduction process in a sulfate bath, investigation on the mechanism of metal precipitation is of great importance.
In the present work, study on the kinetics of cobalt electrowinning and the mechanism of the involved reactions have
been carried out. The obtained results, confirm the mechanism of cobalt precipitation by depletion of hydroxides. The
effects of temperature and scan rate parameters were studied on electrowinning of cobalt by cyclic voltammetry
technique. The diffusion coefficient and rate constant of the reactions were measured and calculated by performed
experiments.
Nowadays cobalt is mostly produced through the electrowinning process of sulfate solutions. Regarding to
S. E. El-Shereafy, E. A. Gomaa, A.m. Yousif, A. Abou Elyazed,
Volume 14, Issue 4 (12-2017)
Abstract
The redox behavior for bulk and nano silver nitrate (NSN) were studied by cyclic voltammetry technique in absence and presence of cefdinir antibiotic (CFD) using glassy carbon electrode (GCE) in 0.1 M KNO3 as supporting electrolyte at two different temperatures. Scan rates were studied for the redox reactions of bulk and nano silver nitrate (NSN) in absence and presence of cefdinir antibiotic (CFD) and mechanism of the electrode reactions were discussed. The stability constant of complexation and thermodynamic parameters for a system were evaluated
M. Ghasemian Safaei, Dr. S. Rastegari, R. Latifi,
Volume 17, Issue 2 (6-2020)
Abstract
In this study, Si-modified aluminide coating on nickel-base superalloy IN-738LC was prepared using a pack cementation method with various powder compositions at 1050 °C for 6 h. The cyclic oxidation test was conducted at 1000 °C followed by cooling at room temperature for 200 h and 20 cycles. The effect of powder composition and the way of cooling on the coatings microstructure and oxidation behavior were studied. Investigations carried out using a scanning electron microscope (SEM), EDS analysis, and XRD. Microstructural observations revealed that the coating thickness of 293 and 274 µm was achieved in the case of using pure Al and Si powder and alloyed Al-20wt.%Si one in the packed mixture, respectively. It was also found that utilizing pure Al and Si powder with NH4Cl as an activator in the pack led to the formation of silicide coating, owing to the higher diffusion of Si, which showed superior cyclic oxidation performance.
Hassan Tarikhum, Basil A Abdullah, Furqan Almyahi, Mazin Mahdi,
Volume 20, Issue 2 (6-2023)
Abstract
In this study, poly(3-hexylthiophene) (P3HT) and fullerene Indene-C60 multi-adducts (ICxA) were blended to create a formulation as a solution and thin films, which were prepared under ambient conditions. The optical properties of various compositional ratios were studied using UV-Visible absorbance and photoluminescence (Pl) measurements. The energy gaps of the prepared thin films and solutions were determined, and their values increased with increasing fullerene ratio because of the isolation of P3HT chains from their neighbors. Intensity ratio (IC=C/IC-C) with a small value in addition to a low value of full width at high maximum (FWHM) of Raman spectra are associated with increased conformation and high aggregation of composition. Furthermore, according to X-ray diffraction (XRD) results the 1:0.8 and 1:0.6 ratios have the largest crystallite sizes in comparison to the other ratios. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels for blends by electrochemical measurements were determined, which are sandwiched between those of the pure materials. In ambient conditions, binary organic photovoltaic cells (OPVs) at different ratios of the photoactive layer were evaluated. The device with a ratio of 1:0.6 had the best performance, with power conversion efficiency (PCE) of 1.21 %, open circuit voltage (VOC) of 0.53 V, short circuit current density (JSC) of 5.71 mA.cm-2, and fill factor (FF) of 39.5 % at a small Vloss of 1.39 V.
Hadi Sharifidarabad, Alireza Zakeri, Mandana Adeli,
Volume 21, Issue 3 (9-2024)
Abstract
The sensitivity of lead dioxide coating properties to the deposition conditions and electrolyte composition has allowed the preparation of coatings with different properties for different applications. In this study, the effects of electrolyte additives on the electrodeposition process were investigated using electrochemical measurements such as cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The results showed that the presence of fluoride ions significantly reduce the possibility of TiO2 formation. The addition of copper ions not only prevents lead loss at the cathode, but also leads to the formation of copper oxide on the surface at initial stages, which hinders nucleation of PbO2. The presence of sodium dodecyl sulfate (SDS) also interferes with the nucleation process as it occupies active nucleation sites. The α-PbO2 interlayer prevents copper oxidation and solves the problem of lead dioxide nucleation. Finally, it was found that the simultaneous use of all additives together with the α-PbO2 interlayer has a positive effect on the coating process.
