ASTM G59-23
(Test Method)Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements
Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements
SIGNIFICANCE AND USE
3.1 This test method can be utilized to verify the performance of polarization resistance measurement equipment including reference electrodes, electrochemical cells, potentiost- ats, scan generators, and measuring and recording devices. The test method is also useful for training operators in sample preparation and experimental techniques for polarization resistance measurements.
3.2 Polarization resistance can be related to the rate of general corrosion for metals at or near their corrosion potential, Ecorr. Polarization resistance measurements are an accurate and rapid way to measure the general corrosion rate. Real-time corrosion monitoring is a common application. The technique can also be used as a way to rank alloys, inhibitors, and so forth in order of resistance to general corrosion.
3.3 In this test method, a small potential scan, ΔE(t), defined with respect to the corrosion potential (ΔE = E – Ecorr), is applied to a metal sample. The resultant currents are recorded. The polarization resistance, RP, of a corroding electrode is defined from Eq 1 as the slope of a potential versus current density plot at i = 0 (1-4):3
The current density is given by i. The corrosion current density, icorr, is related to the polarization resistance by the Stern-Geary coefficient, B. (3),
The dimension of Rp is ohm-cm2, icorr is muA/cm2, and B is in V. The Stern-Geary coefficient is related to the anodic, ba, and cathodic, bc, Tafel slopes in accordance with Eq 3.
The units of the Tafel slopes are V. The corrosion rate, CR, in mm per year can be determined from Eq 4 in which EW is the equivalent weight of the corroding species in grams and ρ is the density of the corroding material in g/cm3.
Refer to Practice G102 for derivations of the above equations and methods for estimating Tafel slopes.
3.4 The test method may not be appropriate to measure polarization resistance on all materials or in all environments. See 8.2 for a discussi...
SCOPE
1.1 This test method covers an experimental procedure for polarization resistance measurements which can be used for the calibration of equipment and verification of experimental technique. The test method can provide reproducible corrosion potentials and potentiodynamic polarization resistance measurements.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G59 − 23
Standard Test Method for
Conducting Potentiodynamic Polarization Resistance
1
Measurements
This standard is issued under the fixed designation G59; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
3.1 This test method can be utilized to verify the perfor-
1.1 This test method covers an experimental procedure for
mance of polarization resistance measurement equipment in-
polarization resistance measurements which can be used for the
cluding reference electrodes, electrochemical cells, potentiost-
calibration of equipment and verification of experimental
ats, scan generators, and measuring and recording devices. The
technique. The test method can provide reproducible corrosion
test method is also useful for training operators in sample
potentials and potentiodynamic polarization resistance mea-
preparation and experimental techniques for polarization resis-
surements.
tance measurements.
1.2 The values stated in SI units are to be regarded as
3.2 Polarization resistance can be related to the rate of
standard. No other units of measurement are included in this
general corrosion for metals at or near their corrosion potential,
standard.
E . Polarization resistance measurements are an accurate and
corr
1.3 This standard does not purport to address all of the
rapid way to measure the general corrosion rate. Real-time
safety concerns, if any, associated with its use. It is the
corrosion monitoring is a common application. The technique
responsibility of the user of this standard to establish appro-
can also be used as a way to rank alloys, inhibitors, and so forth
priate safety, health, and environmental practices and deter-
in order of resistance to general corrosion.
mine the applicability of regulatory limitations prior to use.
3.3 In this test method, a small potential scan, ΔE(t), defined
1.4 This international standard was developed in accor-
with respect to the corrosion potential (ΔE = E – E ), is
corr
dance with internationally recognized principles on standard-
applied to a metal sample. The resultant currents are recorded.
ization established in the Decision on Principles for the
The polarization resistance, R , of a corroding electrode is
P
Development of International Standards, Guides and Recom-
defined from Eq 1 as the slope of a potential versus current
3
mendations issued by the World Trade Organization Technical
density plot at i = 0 (1-4):
Barriers to Trade (TBT) Committee.
] ΔE
R 5 (1)
S D
p
] i
i50, dE/dt→0
2. Referenced Documents
2 The current density is given by i. The corrosion current
2.1 ASTM Standards:
density, i , is related to the polarization resistance by the
corr
G3 Practice for Conventions Applicable to Electrochemical
Stern-Geary coefficient, B. (3),
Measurements in Corrosion Testing
B
G5 Reference Test Method for Making Potentiodynamic
6
i 5 10 (2)
corr
R
Anodic Polarization Measurements
p
G102 Practice for Calculation of Corrosion Rates and Re-
2 2
The dimension of R is ohm-cm , i is muA/cm , and B is
p corr
lated Information from Electrochemical Measurements
in V. The Stern-Geary coefficient is related to the anodic, b ,
a
and cathodic, b , Tafel slopes in accordance with Eq 3.
c
b b
a c
1
This test method is under the jurisdiction of ASTM Committee G01 on B 5 (3)
2.303~b 1b !
a c
Corrosion of Metals and is the direct responsibility of Subcommittee G01.11 on
Electrochemical Measurements in Corrosion Testing.
The units of the Tafel slopes are V. The corrosion rate, CR,
Current edition approved June 1, 2023. Published June 2023. Originally
in mm per year can be determined from Eq 4 in which EW is
approved in 1978. Last previous edition approved in 2020 as G59 – 97 (2020). DOI:
10.1520/G0059-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
G59 − 23
the equivalent weight of the corroding species in grams and ρ 5.4 If the observed results are different than expected, the
3
is the density of the corroding
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: G59 − 97 (Reapproved 2020) G59 − 23
Standard Test Method for
Conducting Potentiodynamic Polarization Resistance
1
Measurements
This standard is issued under the fixed designation G59; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers an experimental procedure for polarization resistance measurements which can be used for the
calibration of equipment and verification of experimental technique. The test method can provide reproducible corrosion potentials
and potentiodynamic polarization resistance measurements.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
G3 Practice for Conventions Applicable to Electrochemical Measurements in Corrosion Testing
G5 Reference Test Method for Making Potentiodynamic Anodic Polarization Measurements
G102 Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements
3. Significance and Use
3.1 This test method can be utilized to verify the performance of polarization resistance measurement equipment including
reference electrodes, electrochemical cells, potentiostats,potentiost-
ats, scan generators, and measuring and recording devices. The test method is also useful for training operators in sample
preparation and experimental techniques for polarization resistance measurements.
3.2 Polarization resistance can be related to the rate of general corrosion for metals at or near their corrosion potential, E .
corr
Polarization resistance measurements are an accurate and rapid way to measure the general corrosion rate. Real time Real-time
corrosion monitoring is a common application. The technique can also be used as a way to rank alloys, inhibitors, and so forth
in order of resistance to general corrosion.
1
This test method is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.11 on Electrochemical
Measurements in Corrosion Testing.
Current edition approved Nov. 1, 2020June 1, 2023. Published November 2020June 2023. Originally approved in 1978. Last previous edition approved in 20142020 as
G59G59 – 97 (2020). – 97 (2014). DOI: 10.1520/G0059-97R20.DOI: 10.1520/G0059-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
G59 − 23
3.3 In this test method, a small potential scan, ΔE(t), defined with respect to the corrosion potential (ΔE = E – E ), is applied
corr
to a metal sample. The resultant currents are recorded. The polarization resistance, R , of a corroding electrode is defined from
P
3
Eq 1 as the slope of a potential versus current density plot at i = 0 (1-4):
] ΔE
R 5 (1)
S D
p
] i
i50, dE/dt→0
The current density is given by i. The corrosion current density, i , is related to the polarization resistance by the Stern-Geary
corr
coefficient, B.(3),
B
6
i 5 10 (2)
corr
R
p
2 2
The dimension of R is ohm-cm , i is muA/cm , and B is in V. The Stern-Geary coefficient is related to the anodic, b , and
p corr a
cathodic, b , Tafel slopes as per in accordance with Eq 3.
c
b b
a c
B 5 (3)
2.303~b 1b !
a c
The units of the Tafel slopes are V. The corrosion rate, CR, in mm per year can be determined from Eq 4 in which EW is the
3
equivalent weight of
...
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