| Electrochemical
Noise |
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| Electrochemical Noise, commonly
abbreviated ECN, is an electrochemical technique in which the potential
and/or current signals that arise directly from the electrochemical
reactions taking place on an electrode surface are measured and
interpreted.
ECN is of intense ongoing interest because of the totally non-invasive nature of the measurement when performed with a Zero Resistance Ammeter (ZRA). The electrochemical instrument is not applying any signal to the sample that might improperly influence the result. This perturbation may be of concern in every electrochemical experiment other than noise. As as comment, ECN can also be measured with the electrochemical instrument configured as a potentiostat or galvanostat. The number of actual applications of this sort is quite small. Most ECN experiments are carried out with ZRA's, so that no signal at all is applied to the sample by the instrument. ECN has been used to monitor localized corrosion (pitting), uniform corrosion through measurement of the Noise Resistance, and the deterioration of paints on metal substrates. ECN does not yet enjoy the level of acceptance of DC techniques and Electrochemical Impedance Spectroscopy. For the last several years, Technical Symposia on Electrochemical Noise have been held at the annual NACE meeting (www.nace.org) with spirited participation from a number of researchers. An excellent place to start your examination of electrochemical noise is "Electrochemical Impedance and Noise", Robert Cottis and Stephen Turgoose, National Association of Corrosion Engineers, 1440 South Creek Drive, Houston, TX 77084-4906, USA. Phone: 281-228-6200. Fax: 281-228-6300. ISBN: 1-57590-093-9. A thorough discussion of the analysis of electrochemical noise ("Interpretation of Electrochemical Noise Data") by Dr. Bob Cottis of UMIST can be found in CORROSION, 57, 265 (2001).
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| Instrumentation for Electrochemical Noise Measurement from Gamry | ||
| We can say confidently, without fear of
contradiction, that the ESA400
Electrochemical Signal Analyzer from Gamry, combined with a Gamry
Potentiostat, is the most advanced instrumentation system for noise that
is commercially available.
The EN120 Electrochemical Noise Software can also be used with Gamry Potentiostats. While the EN120 does not offer the sophistication of the ESA400, it is multiplexable, i.e., your Potentiostat can be multiplexed to several samples using the ECM8 Multiplexer. Gamry software will control an older PC3
Potentiostat for Electrochemical Noise Measurements. Be aware,
however, that the PC3 does not have the capability to offset the measured
potential, increase the gain, and make a higher resolution potential measurement. The potential noise measured with a PC3, then, is
likely to be at a lower resolution than with a PC4 or PCI4
Potentiostat. |
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Batteries
| Fuel
Cells | Corrosion
| Paints
& Coatings | Physical
Electrochemistry |
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Gamry
Instruments © 1997-2004
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