ASTM Standardization of Electrochemical Noise Measurement

Abstract

The increased utilization of electrochemical noise measurement in corrosion research and industrial process monitoring prompted the formation in 1991 of an ASTM Task Group within the G1 Corrosion of Metals Committee. The scope of the task group was to “develop standards that describe instruments and methods for making and analyzing electrochemical noise measurements.” Task group activities are focused exclusively on measurements to be made in the laboratory. The initial goal has been to develop consensus on: (a) terminology, (b) specifications and configurations for laboratory instrumentation, (c) laboratory apparatus, and (d) data analysis methods. A round robin was also organized to develop a body of data on different material/environment systems using a variety of instrument configurations and data analysis techniques. A guide for making valid electrochemical noise results is being prepared based on the round robin results. The status of the effort to address these and other standardization issues within the ASTM G1.11.04 Task Group on Electrochemical Noise Measurement will be presented.

A critical review of electrochemical noise measurement as a tool for evaluation of organic coatings

“…Implementation of analogue and digital filters, although they can be effective in removing systematic noise at frequencies lower and higher than the frequency of interest, will not be useful if the extraneous noise is within the range of frequency of interest for corrosion applications, e.g 1 Hz. Guidelines for the calibration of noise measuring device, including the use of a dummy cell with a known level of noise together with a sine wave signal generator is given in references [15,48]. It should be noted that the level of current noise generated by coated metals with very high resistance coatings is often very low and could be in the order of 10 -11 to 10 -13 A.cm 2 [33,49,50].…”

“…The currently available ZRAs in the market able to accurately detect currents at femtoamp level are expected to readily provide sufficient sensitivity. The dangling leads method in open circuit configuration was suggested by Kearns et al [48] to check the lowest levels of current noise that can be measured by the ZRA. This method involves leaving the WEs and RE terminals of instrument un-connected whilst performing noise measurement.…”

Electrochemical Techniques for Corrosion and Tribocorrosion Monitoring: Methods for the Assessment of Corrosion Rates

“…Also, the discussion is not about how to set up and conduct electrochemical corrosion or tribocorrosion experiments. Such information can be readily found in instruction guidelines manual or standard references [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The accent is put on the interest and validity of combination techniques to provide a better understanding of the corrosion process and more reliable predictions.…”

“…Effective and convenient ways include the removal of unwanted environmental and instrumental noise from the electrochemical noise, e.g., by shielding electrical connections/wires for coupling the electrodes to the experimental apparatus, by using a Faraday cage to exclude electrostatic/electromagnetic influences, even by implementing analogue/digital filters to eliminate systematic noise at frequencies different than the frequency of interest, and so on. Guidelines for the calibration of noise measuring device can be found elsewhere [13,59].…”

“…It has been shown that the use of a single data set of potential and current noise [32] would yield identical values of R SN as calculated by either Eqs. (13) or (14). In some cases, R SN 0 is bound to R N or R P as,…”