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Showing 3 results for K. Raeissi
COMPARISON OF ELECTRODEPOSITION ASPECTS AND CHARACTERISTICS OFNi-WAND Co-WALLOYNANOCRYSTALLINE COATINGS
Z. Ghaferi, K. Raeissi, M. A. Golozar,, A. Saatchi, S. Kabi,
Volume 7, Issue 4 (Autumn 2010 2010)
Abstract

Abstract:

current densities. Electrochemical impedance spectroscopy (EIS) results showed that the codeposition mechanism of

tungsten in Ni-W deposition is the reduction of tungsten oxide which changed to the reduction of tungsten-containing

ion complexes at higher current densities. In Co-W electrodeposition, the tungsten codeposition takes place via

reduction of tungsten oxide, although, the role of tungsten-containing complexes at higher current densities cannot be

ruled out. The surface morphology of Ni-W coatings was crack-free and was strongly dependent on deposition current

density. In addition, higher grain size and lower tungsten content were obtained by increasing the current density. In

Co-W coatings, no obvious variation in surface morphology was observed except for the fine cracks appeared at

higher current densities. In this system the grain size remained almost constant with increasing current density. The

microhardness values of Ni-W and Co-W coatings decreased due to the increase in the grain size and/or decrease in

tungsten content.

Ni-W and Co-W alloy nanocrystalline coatings were electrodeposited on copper substrate at different
EFFECT OF SUBSTRATE TEXTURE AND DEPOSITION CURRENT DENSITY ON PROPERTIES OF NiNANOCRYSTALLINE ELECTRODEPOSITS
M. R. Zamanzad-Ghavidel,, K. Raeissi, A. Saatchi,
Volume 9, Issue 2 (june 2012 2012)
Abstract
Abstract: Nickel was electrodeposited onto copper substrates with high {111} and {400} peak intensities. The grain size of coatings deposited onto the copper substrate with a higher {111} peak intensity was finer. Spheroidized pyramid morphology was obtained at low current densities on both copper substrates. By increasing the deposition current density, grain size of the coating was increased for both substrates and eventually a mixed morphology of pyramids and blocks was appeared without further increase in grain size. This decreased the anodic exchange current density probably due to the decrease of surface roughness and led to a lower corrosion rate.
EFFECTS OF TiO2 ADDITIVE ON ELECTROCHEMICAL HYDROGEN STORAGE PROPERTIES OF NANOCRYSTALLINE /AMORPHOUS Mg2Ni INTERMETALLIC ALLOY
A. Shahcheraghi, F. Dehghani, K. Raeissi, A. Saatchi, M. H. Enayati,
Volume 10, Issue 1 (march 2013)
Abstract
Abstract: Mg2Ni alloy and Mg2Ni–x wt% TiO2 (x = 3, 5 and 10 wt %) composites are prepared by mechanical alloying. The produced alloy and composites are characterized as the particles with nanocrystalline/amorphous structure. The effects of TiO2 on hydrogen storage properties are investigated using anodic polarization and electrochemical impedance spectroscopy. It is demonstrated that the initial discharge capacity and exchange current density of hydrogen are increased by adding 5wt% TiO2, while the cycle stability and bulk hydrogen diffusivity don’t change. It is found that the charge transfer resistance of Mg2Ni–5wt% TiO2 composite is lower than that of Mg2Ni alloy. On the other hand, the hydrogen oxidation during the discharge process proceeds more easily on the electrode surface containing TiO2 additive.
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