Description. ASTM G Standard Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements. View more. ASTM G()e1. Standard Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements. ASTM-G Standard Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements – corrosion.
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ASTM G102 Standard Practice
These g10 are known as Potential-pH Pourbaix diagrams and have been published by several authors 2, 3. Link to Active This link will always route to the current Active version of the standard. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Values of 65 and mV are also commonly used.
In this case, the concentration of the corroding electrode ions is generally of the same magnitude or higher than other ions y102 in the corrosion process in the electrolyte surrounding the electrode. NOTE 2—Mid-range values were assumed for concentrations of alloying elements.
Corrosion Current Density 4. Calculation methods for converting corrosion current density values to either mass loss rates or average penetration rates are given for most engineering alloys. This is accomplished by dividing the total current by the geometric area of the electrode exposed to the solution.
KRT b 5 nF 9 where: The estimation of a B value for situations involving mixed control requires more information in general and is beyond the scope of this standard.
ASTM G Standard Practice – Free Download PDF
This will make results from different studies more comparable and minimize calculation errors that may occur in transforming electrochemical results to corrosion rate values. Although the conversion of these current values into mass loss rates or penetration rates is based on Faraday’s Law, the calculations can be complicated for alloys and metals with elements having multiple valence values. Consequently, the Stern-Geary constant B will be in? Some typical values of equivalent weights for a variety of g1102 and alloys are provided.
This is equivalent to the calculation shown in 4. A sample calculation is given in Appendix X1. This practice is intended to provide guidance in calculating mass loss and penetration rates for such alloys. In most programmable potentiodynamic polarization equipment, the current is converted to current density automatically and the resulting plot is of i versus E. B Registered trademark Haynes International. Rp 5 Ra 2 rl 11 where: In addition, some guidelines for converting polarization resistance values to corrosion rates are provided.
The reaction under mixed control will have an apparently larger b value than predicted for an activation control, and a plot of E versus log I will tend to curve to an asymptote parallel to the potential axis. In this case, the magnitude of the error is proportional to y102 rate. Historical Version s – view previous versions of standard.
Some approaches for estimating this information are given.
A number in parentheses indicates the year of last reapproval. No other aastm of measurement are included in this standard. Current edition approved Feb.
The capacitance charging effect will cause the calculated polarization resistance to be in error. Wi 4 unless a better basis is available. It is usually assumed that the process of oxidation is uniform and Copyright? B icor 5 R 10 p where: B5 ba bc 2. This standard is subject to revision at any time by the responsible technical committee and must v102 reviewed every?
NOTE 4— Eq 4 was used to make these calculations.
Q 5 Wi 3 where: