scholarly journals Investigation of Velocity Influence on Cathodic Polarization of Aluminum Alloys in 3.5% NaCl by Electrochemical Impedance Spectroscopy

2019 ◽  
Vol 12 (Summer and Autumn 2019) ◽  
pp. 25-30
Author(s):  
karim akbari vakilabadi ◽  
Hosein Khanzadi ◽  
◽  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Aluminum Alloys ◽  
Impedance Spectroscopy ◽  
Cathodic Polarization ◽  
Electrochemical Impedance

Effect of the Fe/Cu Relationship Corrosion and low Alloying Elements on Corrosion Behavior of Cast Aluminum Parts

2016 ◽  
Vol 1815 ◽  
Author(s):  
C. Rodríguez-Rivera ◽  
J.A. García-Hinojosa ◽  
F.J. Rodríguez-Gómez
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Aluminum Alloys ◽  
Impedance Spectroscopy ◽  
Corrosion Rate ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Corrosion Morphology

ABSTRACTThe aim of this study is to compare the corrosion rate of aluminum alloys for ornamental pieces. Three Fe/Cu relationships were tested in order to improve hardness and brightness in aluminum pieces since these alloys are used in the making of ornamental pieces. The variation on Fe/Cu content could result in modification on corrosion rate, since a metallographic characterization must be carried out identifying the presence of intermetallic phases. The presence of these elements could result in increasing corrosion rate, or even in modification of corrosion morphology, so localized corrosion could be expected.The assessment of corrosion rate was carried out in saline media, since chlorides are ions that promote localized corrosion. Electrochemical techniques (polarization curves and Tafel plots) were used in order to evaluate the attack in aluminum pieces; electrochemical impedance spectroscopy was also employed with voltage amplitude of 10 mV rms, and a frequency range from 10,000 Hz to 0.01 Hz. A typical three electrodes cell was used, exposing an area of one cm2. Before polarization, open circuit potential was monitored for an hour looking for a steady state. All conditions were tested for triplicate.The behavior of open circuit potential vs. time, and polarization curves was analyzed; a corrosion mechanism is proposed according to the electrochemical control. Polarization rate was calculated by using Tafel plots and, an electrochemical impedance spectroscopy analysis by using equivalent electric circuits is shown. Electrochemical impedance will yield information about corrosion morphology that is backed with microscopic inspection.The objective of this study is to compare the corrosion rate of aluminum alloys for ornamental pieces in order to determine the effect of the relationship Fe/Cu on the corrosion mechanism in aluminum parts for ornamental pieces.

Studies on Estimating Methods of Polarization Performance for Coated Steel in Seawater

2010 ◽  
Vol 654-656 ◽  
pp. 2418-2421 ◽  
Author(s):  
Yu Hong Qi ◽  
Zhan Ping Zhang ◽  
Mei Miao ◽  
Xia Zhen Zhang
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Potential Distribution ◽  
Cathodic Polarization ◽  
Electrochemical Impedance ◽  
Electrochemical Measurement ◽  
Coated Steel ◽  
Coating Properties ◽  
Polarization Data ◽  
Measured Polarization

The polarization curves and electrochemical impedance spectroscopy of coated steel after scratching cross-lines or cathodic polarization using COLT system connected to electrochemical workstation IM6ex in seawater are investigated and from the measured polarization data, potential distribution on hull surface under waterline are predicted using Beasy CP software. It is shown that an more pricise method for gaining polarization data of the coated steel in seawater is the electrochemical measurement carried out by COLT system and the method of scratching cross-lines or cathodic polarization for coating damage is simple and convenient for estimating the polarization data of a new coated hull that is closely related to the coating properties.

CATHODIC DISBONDING OF INDUSTRIAL CHLORINATED RUBBER-BASED PRIMER USED IN RUBBER/METAL COMPOSITES: AN ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY ANALYSIS

2016 ◽  
Vol 89 (4) ◽  
pp. 712-723 ◽  
Author(s):  
I. Ismail ◽  
M. K. Harun
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Cathodic Polarization ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Time Interval ◽  
Significant Drop ◽  
Coating Degradation ◽  
Adhesion Failure ◽  
Bode Plots

ABSTRACT Chemlok 205 primer is a common bonding agent used together with a top coat in rubber/metal–bonded composites. Recent studies indicated that a stand-alone Chemlok 205 primer failed when its metal substrate underwent corrosion. The failure was suspected to be caused by coating degradation, followed by cathodic disbonding, induced from the corrosion reaction. Therefore, in this work, the effect of cathodic polarization on the coating delamination was further investigated. The work intends to focus on understanding the adhesion failure processes involved. Thus, electrochemical impedance spectroscopy (EIS) was employed on a stand-alone industrial coating Chemlok 205 primer on mild steel substrate subjected to cathodic polarization potential of −0.8 V versus Ag/AgCl reference electrode in 0.5 M NaCl. The coating barrier properties were interpreted through Nyquist and Bode plots of the EIS plots for a selected time interval. The data obtained were modeled against three distinguished electrical equivalent circuits representing the stages of coating degradation against time. Analysis through Nyquist and Bode plots indicated that the stand-alone Chemlok 205 primer coating experienced a significant drop in coating impedance before experiencing adhesion loss. The changes in the coating capacitance and coating resistance indicated that the coating underwent degradation first before adhesion failure.

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