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oxidation-currents
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Effects of current density on microstructure and corrosion property of coating on AZ31 Mg alloy processed via plasma electrolytic oxidation
, Article Magnesium Technology ; February , 2014 , pp. 345-349 ; ISSN: 15454150 ; ISBN: 9781118888162 ; Einkhah, F ; Sani, M. A. F ; Ko, Y. G ; Shin, D. H ; Sharif University of Technology
Abstract
The effects of the current density on the microstructure and the corrosion property of the coating on AZ31 Mg alloy processed by the plasma electrolytic oxidation (PEO) were investigated. The present coatings were produced in an acid electrolyte containing K2ZrF6 with three different current densities, i.e., 100, 150, and 200 mA/cm2. From the microstructural observations, as the applied current density was increased, the diameter of micro-pores formed by the plasma discharges with high temperature increased. The coatings on AZ31 Mg alloy were mainly composed of MgO, ZrO 2, MgF2, and Mg2Zr5O12 phases. The results of potentiodynamic polarization clearly showed that the PEO-treated AZ31 Mg...
A comparative study of the electrooxidation of ethylene glycol on transition metal electrodes in alkaline solution
, Article Journal of New Materials for Electrochemical Systems ; Volume 15, Issue 4 , 2012 , Pages 255-263 ; 14802422 (ISSN) ; Jafarian, M ; Shahnazi Sangachin, A. A ; Gobal, F ; Sharif University of Technology
2012
Abstract
Electrodes made of group VIII and IB metals were examined for their redox process and electrocatalytic activities towards the oxidation of ethylene glycol in alkaline solutions. The method of cyclic voltammetery (CV) and Open circuit potentials measurement (OCP) was employed. It is found that considerable electrooxidation current are observed for silver and copper but lower anodic overpotential for oxidation is obtained for gold and platinum. Oxide layer produced on the surface of all electrodes in alkaline solution under anodic scan participates in ethylene glycol electrooxidation. Oxidation current observed in the reverse scans for platinum and gold are higher than those observed in...
Microstructural developments and electrical properties of novel coarse-grained SnO2 varistors obtained by CuO addition for low-voltage applications
, Article Ceramics International ; Volume 44, Issue 15 , 2018 , Pages 18478-18483 ; 02728842 (ISSN) ; Mahmoudi, P ; Golmohammad, M ; Delshad Chermahini, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This research focused on making novel low-voltage SnO2 varistors by CuO addition on conventional high-voltage SnO2 varistors. Moreover, the withstand surge capability of samples was studied. The results showed that CuO addition enhances grain growth of SnO2 and coarse-grained SnO2 varistors with simple microstructures were acquired in 1 mol% CuO-doped sample. This coarse-grained SnO2 varistor presented a high nonlinear coefficient (23) and low leakage current density (23 µA/cm2) with low breakdown field value of 0.6 kV/cm. Despite the large grain size, the low residual voltage ratio (2.3) was obtained for this sample compared to the CuO-free sample. The decrease in grain electric resistivity...