Electrochemical Methods for On-Site Determinations of Corrosion Rates of Rebars

2009 ◽  
pp. 107-107-12 ◽  
Author(s):  
S Feliú ◽  
JA González ◽  
C Andrade
Keyword(s):  
Electrochemical Methods ◽  
Corrosion Rates

An Instrumented Field Corrosion Test Loop

1998 ◽  
Author(s):  
Alebachew Demoz ◽  
Kirk H. Michaelian ◽  
John Donini ◽  
Sankara Papavinasam ◽  
R. Winston Revie
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Corrosion Test ◽  
Visual Inspection ◽  
Electrochemical Methods ◽  
Corrosion Rates ◽  
Test Loop ◽  
The Media ◽  
Electrochemical Monitoring ◽  
Multi Phase

A multi-purpose instrumented loop in line with an oil producing well is described. The loop has several ports for coupons which were replaced periodically. Some of the coupons were used for electrochemical monitoring in addition to weight loss and visual inspection. Weight loss, pit rate and all the electrochemical methods used gave corrosion rates that were dependent on the positions of the coupons inside the loop. The corrosion rate of the coupons increased from top to bottom. This order reflected the media and flow to which the coupons were exposed in a multi-phase producing well.

The Validity of Electrochemical Methods for Measuring Corrosion Rates of Copper-Nickel Alloys in Sea Water

CORROSION ◽  
1979 ◽  
Vol 35 (11) ◽  
pp. 505-509 ◽  
Author(s):  
BARRY C. SYRETT ◽  
DIGBY D. MACDONALD
Keyword(s):  
Weight Loss ◽  
Linear Polarization ◽  
Polarization Resistance ◽  
Nickel Alloys ◽  
Sea Water ◽  
Ac Impedance ◽  
Electrochemical Methods ◽  
Potential Step ◽  
Corrosion Rates ◽  
Copper Nickel

Abstract This work was stimulated by reports that electrochemical methods for measuring the polarization resistance of copper, nickel, or copper-nickel alloys in aqueous systems may lead to appreciable errors in the estimates of the corrosion rate. In the present work, the polarization resistance (Rp) of two copper-nickel alloys (90:10 Cu:Ni and 70:30 Cu:Ni) was monitored as a function of time in flowing sea water that contained 0.045, 0.85, 6.6, or 26.3 mg/dm3 dissolved oxygen. Rp values were obtained using the linear polarization, potential step, and AC impedance techniques. The total weight loss during the test period was calculated from the area under the 1/Rp versus time curve and compared with the measured weight loss. The experimental data support the validity of electrochemical methods for measuring corrosion rates of copper-nickel alloys in sea water, provided that a sufficient number of Rp measurements are made during the first 24 hours, and provided that proper consideration is given to the capacitive elements of the metal/solution interfacial impedance. Previous reports that electrochemical measurements may lead to underestimates of the corrosion rates are thought to have resulted primarily from undetected (and very high) corrosion rates at short exposure times. Reported overestimates of the corrosion rates are thought to have resulted from the use of a potential sweep rate that was too high (linear polarization technique), a time for current decay that was too short (potential step technique), or excitation frequencies that were insufficiently low (AC impedance technique).

Corrosion Behavior of MRI153M Magnesium Alloy in 3% NaCl Solution

2015 ◽  
Vol 227 ◽  
pp. 83-86
Author(s):  
Ohad Gaon ◽  
Barbara Kazanski ◽  
Alex Lugovskoy
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Electrochemical Methods ◽  
Gas Evolution ◽  
Linear Polarization Resistance ◽  
Corrosion Rates ◽  
Die Cast ◽  
Good Agreement

Corrosion behavior of high-pressure die cast creep resistant magnesium alloy MRI 153M in 3% NaCl aqueous solution was studied by several electrochemical and non-electrochemical techniques. The electrochemical techniques were Electrochemical Impedance Spectroscopy (EIS), Linear Polarization Resistance (LPR) and Tafel-slope Polarization. The non-electrochemical techniques were mass-loss and gas evolution measurements. Values of corrosion rates were calculated and the morphology of corroded surface studied. While corrosion rates calculated by both non-electrochemical methods are not consistent, those gained by the three electrochemical methods demonstrate consistency. In general, the rate of corrosion calculated by the gas evolution method is in a good agreement with the corrosion rate calculated from the electrochemical methods, which should be an indication of mixed chemical-electrochemical character of the process. SEM and light microscope observation of corroded specimens demonstrated the localized character of corrosion, at least at the initial stages.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

Mcc Corrosion Tests at Reference Testing Conditions for A27 Cast steel in Hanford Ground Water

1986 ◽  
Vol 84 ◽  
Author(s):  
M.D. Merz ◽  
F. Gerber ◽  
R. Wang
Keyword(s):  
Pacific Northwest ◽  
Pressure Vessel ◽  
Static Pressure ◽  
Cast Steel ◽  
Statistical Treatment ◽  
Testing Conditions ◽  
Corrosion Tests ◽  
Corrosion Rates ◽  
High Level Nuclear Waste ◽  
High Level

AbstractThe Materials Characterization Center (MCC) at Pacific Northwest Lab- oratory is performing three kinds of corrosion tests for the Basalt Waste Isolation Project (BWIP) to establish the interlaboratory reproducibility and uncertainty of corrosion rates of container materials for high-level nuclear waste. The three types of corrosion tests were selected to address two distinct conditions that are expected in a repository constructed in basalt. An air/steam test is designed to address corrosion during the operational period and static pressure vessel and flowby tests are designed to address corrosion under conditions that bound the condi ring the post-closure period of the repository.The results of tests at reference testing conditions, which were defined to facilitate interlaboratory comparison of data, are presented. Data are reported for the BWIP/MCC-105.5 Air/Steam Test, BWIP/MCC-105.1 Static Pressure Vessel, and BWIP/MC-105.4 Flowby Test. In those cases where data are available from a second laboratory, a statistical analysis of interlaboratory results is reported and expected confidence intervals for mean corrosion rates are given. Other statistical treatment of data include analyses of the effects of vessel-to-vessel variations, test capsule variations for the flowby test, and oven-to-oven variations for air/steam tests.

SEPARATION AND CHARACTERIZATION OF ANTHOCYANINS BY ANALYTICAL AND ELECTROCHEMICAL METHODS

2011 ◽  
Vol 10 (5) ◽  
pp. 697-701 ◽  
Author(s):  
Firuta Fitigau ◽  
Claudia Popescu ◽  
Adina-Elena Segneanu ◽  
Ionel Balcu ◽  
Raluca Martagiu ◽  
...  
Keyword(s):  
Electrochemical Methods
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