ASTM G71-81(2003)

Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes

SIGNIFICANCE AND USE
Use of this guide is intended to provide information on the galvanic corrosion of metals in electrical contact in an electrolyte that does not have a flow velocity sufficient to cause erosion-corrosion or cavitation.
This standard is presented as a guide for conducting galvanic corrosion tests in liquid electrolyte solutions, both in the laboratory and in service environments. Adherence to this guide will aid in avoiding some of the inherent difficulties in such testing.
SCOPE
1.1 This guide covers conducting and evaluating galvanic corrosion tests to characterize the behavior of two dissimilar metals in electrical contact in an electrolyte under low-flow conditions. It can be adapted to wrought or cast metals and alloys.
1.2 This guide covers the selection of materials, specimen preparation, test environment, method of exposure, and method for evaluating the results to characterize the behavior of galvanic couples in an electrolyte. Additional information on galvanic corrosion testing and examples of the conduct and evaluation of galvanic corrosion tests in electrolytes are given in Refs (1) through (7).
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2003
• ICS: 25.220.20 - Surface treatment
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.11 - Electrochemical Measurements in Corrosion Testing

Relations

• Replaces: ASTM G71-81(1998)e1 - Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes
• Effective Date: 01-Oct-2003
• Replaced By: ASTM G71-81(2009) - Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes
• Effective Date: 01-May-2009
• Referred By: ASTM G162-18 - Standard Practice for Conducting and Evaluating Laboratory Corrosion Tests in Soils
• Effective Date: 01-Oct-2003
• Referred By: ASTM G82-98(2021)e1 - Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion Performance
• Effective Date: 01-Oct-2003
• Referred By: ASTM G31-21 - Standard Guide for Laboratory Immersion Corrosion Testing of Metals
• Effective Date: 01-Oct-2003
• Referred By: ASTM F3044-20 - Standard Test Method for Evaluating the Potential for Galvanic Corrosion for Medical Implants
• Effective Date: 01-Oct-2003
• Referred By: ASTM G215-17 - Standard Guide for Electrode Potential Measurement
• Effective Date: 01-Oct-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: G 71 – 81 (Reapproved 2003)
Standard Guide for
Conducting and Evaluating Galvanic Corrosion Tests in
1
Electrolytes
ThisstandardisissuedunderthefixeddesignationG 71;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
1.1 This guide covers conducting and evaluating galvanic 3.1 Use of this guide is intended to provide information on
corrosion tests to characterize the behavior of two dissimilar the galvanic corrosion of metals in electrical contact in an
metals in electrical contact in an electrolyte under low-flow electrolyte that does not have a flow velocity sufficient to cause
conditions. It can be adapted to wrought or cast metals and erosion-corrosion or cavitation.
alloys. 3.2 This standard is presented as a guide for conducting
1.2 This guide covers the selection of materials, specimen galvanic corrosion tests in liquid electrolyte solutions, both in
preparation,testenvironment,methodofexposure,andmethod the laboratory and in service environments. Adherence to this
for evaluating the results to characterize the behavior of guide will aid in avoiding some of the inherent difficulties in
galvanic couples in an electrolyte. such testing.
NOTE 1—Additional information on galvanic corrosion testing and
4. Test Specimens
examples of the conduct and evaluation of galvanic corrosion tests in
2 4.1 Material—Testspecimensshouldbemanufacturedfrom
electrolytes are given in Refs (1) through (7).
the same material as those used in the service application being
1.3 This standard does not purport to address all of the
modeled. Minor compositional or processing differences be-
safety concerns, if any, associated with its use. It is the
tween materials or between different heats can greatly affect
responsibility of the user of this standard to establish appro-
the results in some cases.
priate safety and health practices and determine the applica-
4.2 Size and Shape:
bility of regulatory limitations prior to use.
4.2.1 Thesizeandshapeofthetestspecimensaredependent
on restrictions imposed by the test location. When determining
2. Referenced Documents
material behavior in the laboratory, it is advisable to use the
2.1 ASTM Standards:
largest specimens permissible within the constraints of the test
G1 Practice for Preparing, Cleaning, and Evaluating Cor-
equipment.Ingeneral,theratioofsurfaceareatometalvolume
3
rosion Test Specimens
should be large in order to favor maximum corrosion loss per
G3 PracticeforConventionsApplicabletoElectrochemical
weight. Sufficient thickness should be employed, however, to
3
Measurements in Corrosion Testing
minimize the possibility of perforation of the specimens during
G4 Guide for Conducting Corrosion Coupon Tests in Field
the test exposure. When modeling large components, the size
3
Applications
of the specimens should be as large as practical. When
G16 Guide forApplying Statistics toAnalysis of Corrosion
modeling smaller components, specimen size should be as
3
Data
close as possible to that of the application being modeled.
G31 Practice for Laboratory Immersion Corrosion Testing
Surface area ratio in the test should be identical to the
3
of Metals
application being modeled. This ratio is defined as the surface
G46 Guide for Examination and Evaluation of Pitting
area of one member of the couple divided by the surface area
3
Corrosion
of the other member of the couple. Only the area in contact
with the electrolyte (wetted area) is used in this calculation. In
1
This guide is under the jurisdiction ofASTM Committee G01 on Corrosion of
low-resistivity electrolytes, maintaining proximity between the
Metals and is the direct responsibility of Subcommittee G01.11 on Electrochemical
materials being coupled may be more important than maintain-
Measurements in Corrosion Testing.
ing the exact area ratio. Also, with some couples, such as
Current edition approved Oct. 1, 2003. Published October 2003. Originally
e1
approved in 1981. Last previous edition approved in 1998 as G 71 – 81 (1998) .
copper coupled to aluminum, there may be effects of corrosion
2
The boldface numbers in parentheses refer to the list of references appended to
products washing from one electrode to another which may
the practice.
3 have to be considered in determining specimen placement.
Annual Book of ASTM Standards, Vol 03.02.
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G 71 – 81 (2003)
4.2.2 Laboratory tests are normally performed on rectangu- solution shoul
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