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Characterization of Electrodeposits and Electrodeposition Processes
Published in R.K. Pandey, S.N. Sahu, S.N. Sahu, S. Chandra, Handrook Of Semiconductor Electrodeposition, 2017
R.K. Pandey, S.N. Sahu, S.N. Sahu, S. Chandra
The following are some considerations necessary for deciding the exact cell geometry: The working and counter electrodes should be arranged in a manner that yields uniform current distribution. For a parallel electrode geometry, this can be accomplished by insulating the back sides of the electrodes and keeping them a sufficient distance apart.The reference electrode should be kept very near the working electrode. This is normally achieved by using the reference electrode geometry shown in Fig. 5.1a. The electrolyte gets sucked through the capillary (Luggin probe) and acts as a conducting bridge to the reference electrode through an agar-agar salt bridge. The working electrode potential is measured with respect to the reference electrode connected via the Luggin probe. The tip of the Luggin probe is kept sufficiently close to the working electrode without blocking its surface; otherwise it could alter the current distribution and potential profile. Current resistance (iR) compensation for the ohmic drop between the Luggin tip and the working electrode should also be employed. Gileadi et al. (1975) and Sawyer and Roberts (1974) discussed the effect of iR drop, and suitable configurations for the Luggin probe were discussed by Bernartt (1961). The electrolyte may be continuously purged with nitrogen or other inert gas whenever desirable.The counter and working electrode compartments are sometimes separated by a glass frit to avoid contamination of the working electrode environment.
HVOF Deposition, comparative investigation and optimum selection of molybdenum, boron, chromium, and titanium in Iron amorphous composite coatings
Published in Surface Engineering, 2023
Ratnesh Kumar Sharma, Randip Kumar Das, Shiv Ranjan Kumar
Electro-chemical corrosion test was performed to estimate corrosion rate. A Potentiostat-Galvanostat corrosion tester using Gamry software was used to conduct a potentiodynamic polarization test of coating materials based on Fe amorphous composite coatings. Three electrodes – the working electrode, a saturated calomel reference electrode (SCE), and a platinum counter electrode – make up the corrosion tester setup. The potential of the working electrode and the reference electrode was measured using a Luggin probe. The test’s electrolyte was a 3.5 weight percent NaCl solution at 25 degrees Celsius and atmospheric pressure. A scan speed of 1 mV sec−1 was used to assess each test. Corrosion current density was measured from the Tafel plots based on adjusting voltage from −250 mV to +250 mV with respect to open circuit potential.
Effect of chromium–titanium on corrosion and erosion of HVOF coating
Published in Surface Engineering, 2022
Ratnesh Kumar Sharma, Randip Kumar Das, Shiv Ranjan Kumar
A potentiodynamic polarisation test of Fe–Cr–Ti-based coating materials was performed using a Potentiostat–Galvanostat corrosion tester equipped with Gamry software. The corrosion tester setup consisted of three electrodes, which were a working electrode (WE), a saturated calomel electrode (SCE) that was taken as the reference, and a platinum counter electrode (PCE). Luggin probe was used to measure the potential of the working electrode and reference electrode. The electrolyte used for the test was 3.5 wt-% NaCl solution at 25°C under atmospheric pressure. Each test was analyzed at a scan rate of 1 mV sec–1. In order to calculate the corrosion rate, a Tafel plot was drawn by varying the potential from −250 to +250 mV with respect to open circuit potential. The corrosion rate of the samples in 3.5 wt-% NaCl solution was evaluated using Equation (1). Finally, the corroded surface was investigated using SEM analysis.
Corrosion properties of ASTM A615 rock bolt steel in US underground coal mines
Published in Mining Technology, 2020
Gopi Bylapudi, Kanchan Mondal, A. J. (Sam) Spearing, Anand Bhagwat
The calibrated reference and platinum electrodes were cleaned first with deionized water and acetone subsequently before application. The reference electrode was set into the luggin-capillary of the test cell that was filled with the electrolyte solution under investigation. The purpose of this luggin setup was to reduce/eliminate any IR errors (IR drop/Ohmic drop) by connecting the reference close to the surface of the working electrode. IR drop is the potential drop that occurs due to the solution resistance and is unwanted and needs to be eliminated. Typically, the required distance between the luggin probe tip and the working electrode is 2d (where d is the tip diameter), but it is variable based on the test cell design and the working electrode diameter (Oelbner et al. 2006; Doctors 2017). The luggin probe setup in the test cell can be seen in Figure 4.