ASTM G82-98(2003)
(Guide)Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion Performance
Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion Performance
SCOPE
1.1 This guide covers the development of a galvanic series and its subsequent use as a method of predicting the effect that one metal can have upon another metal can when they are in electrical contact while immersed in an electrolyte. Suggestions for avoiding known pitfalls are included.
1.2 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. Specific precautionary statements are given in Section 5.
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Designation:G82–98 (Reapproved 2003)
Standard Guide for
Development and Use of a Galvanic Series for Predicting
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Galvanic Corrosion Performance
ThisstandardisissuedunderthefixeddesignationG82;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.5 galvanic series—a list of metals and alloys arranged
according to their relative corrosion potentials in a given
1.1 This guide covers the development of a galvanic series
environment.
and its subsequent use as a method of predicting the effect that
3.6 noble—thepositive(increasinglyoxidizing)directionof
one metal can have upon another metal can when they are in
electrode potential.
electrical contact while immersed in an electrolyte. Sugges-
3.7 passive—the state of the metal surface characterized by
tions for avoiding known pitfalls are included.
low corrosion rates in a potential region that is strongly
1.2 This standard does not purport to address all of the
oxidizing for the metal.
safety concerns, if any, associated with its use. It is the
3.8 polarization—the change from the open-circuit elec-
responsibility of the user of this standard to establish appro-
trode potential as the result of the passage of current.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific precau-
4. Significance and Use
tionary statements are given in Section 5.
4.1 When two dissimilar metals in electrical contact are
2. Referenced Documents exposed to a common electrolyte, one of the metals can
undergo increased corrosion while the other can show de-
2.1 ASTM Standards:
creasedcorrosion.Thistypeofacceleratedcorrosionisreferred
G3 PracticeforConventionsApplicabletoElectrochemical
2
toasgalvaniccorrosion.Becausegalvaniccorrosioncanoccur
Measurements in Corrosion Testing
at a high rate, it is important that a means be available to alert
G15 Terminology Relating to Corrosion and Corrosion
2
the user of products or equipment that involve the use of
Testing
dissimilar metal combinations in an electrolyte of the possible
G16 GuideforApplyingStatisticstoAnalysisofCorrosion
2
effects of galvanic corrosion.
Data
4.2 Onemethodthatisusedtopredicttheeffectsofgalvanic
G71 Guide for Conducting and Evaluating Galvanic Cor-
2
corrosion is to develop a galvanic series by arranging a list of
rosion Tests in Electrolytes
the materials of interest in order of observed corrosion poten-
3. Terminology
tials in the environment and conditions of interest. The metal
that will suffer increased corrosion in a galvanic couple in that
3.1 Definitions of terms used in this guide are from Termi-
environmentcanthenbepredictedfromtherelativepositionof
nologyG15.
the two metals in the series.
3.2 active—the negative (decreasingly oxidizing) direction
4.3 Types of Galvanic Series:
of electrode potential.
4.3.1 OnetypeofGalvanicSeriesliststhemetalsofinterest
3.3 corrosionpotential—thepotentialofacorrodingsurface
in order of their corrosion potentials, starting with the most
in an electrolyte relative to a reference electrode measured
active (electronegative) and proceeding in order to the most
under open-circuit conditions.
noble (electropositive). The potentials themselves (versus an
3.4 galvanic corrosion—accelerated corrosion of a metal
appropriate reference half-cell) are listed so that the potential
because of an electrical contact with a more noble metal or
differencebetweenmetalsintheseriescanbedetermined.This
nonmetallic conductor in a corrosive electrolyte.
type of Galvanic Series has been put in graphical form as a
series of bars displaying the range of potentials exhibited by
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themetallistedoppositeeachbar.Suchaseriesisillustratedin
This guide is under the jurisdiction ofASTM Committee G01 on Corrosion of
Metals and is the direct responsibility of Subcommittee G01.11 on Electrochemical
Fig. 1.
Measurements in Corrosion Testing.
4.3.2 Thesecondtypeofgalvanicseriesissimilartothefirst
Current edition approved October 1, 2003. Published October 2003. Originally
in that it lists the metals of interest in order of their corrosion
approved in 1983. Last previous edition approved in 1998 as G 82–98.
2
Annual Book of ASTM Standards, Vol 03.02. potentials. The actual potentials themselves are not specified,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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G82–98 (2003)
NOTE—Dark boxes indicate active behavior of active-passive alloys.
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FIG. 1 Galvanic Series of Various Metals in Flowing Seawater at 2.4 to 4.0 m/s for 5 to 15 Days at 5 to 30°C (Red
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