1、Designation:G8298(Reapproved 2014)Standard Guide forDevelopment and Use of a Galvanic Series for PredictingGalvanic Corrosion Performance1This standard is issued under the fixed designation G82;the number immediately following the designation indicates the year of originaladoption or,in the case of
2、revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers the development of a galvanic seriesand its subsequent use as a method of predicting t
3、he effect thatone metal can have upon another metal can when they are inelectrical contact while immersed in an electrolyte.Sugges-tions for avoiding known pitfalls are included.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard
4、.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific precau-t
5、ionary statements are given in Section 5.2.Referenced Documents2.1 ASTM Standards:2G3 Practice for Conventions Applicable to ElectrochemicalMeasurements in Corrosion TestingG15 Terminology Relating to Corrosion and Corrosion Test-ing(Withdrawn 2010)3G16 Guide for Applying Statistics to Analysis of C
6、orrosionDataG71 Guide for Conducting and Evaluating Galvanic Corro-sion Tests in Electrolytes3.Terminology3.1 Definitions of terms used in this guide are from Termi-nology G15.3.2 activethe negative(decreasingly oxidizing)directionof electrode potential.3.3 corrosion potentialthe potential of a corr
7、oding surfacein an electrolyte relative to a reference electrode measuredunder open-circuit conditions.3.4 galvanic corrosionaccelerated corrosion of a metalbecause of an electrical contact with a more noble metal ornonmetallic conductor in a corrosive electrolyte.3.5 galvanic seriesa list of metals
8、 and alloys arrangedaccording to their relative corrosion potentials in a givenenvironment.3.6 noblethe positive(increasingly oxidizing)direction ofelectrode potential.3.7 passivethe state of the metal surface characterized bylow corrosion rates in a potential region that is stronglyoxidizing for th
9、e metal.3.8 polarizationthe change from the open-circuit elec-trode potential as the result of the passage of current.4.Significance and Use4.1 When two dissimilar metals in electrical contact areexposed to a common electrolyte,one of the metals canundergo increased corrosion while the other can sho
10、w de-creased corrosion.This type of accelerated corrosion is referredto as galvanic corrosion.Because galvanic corrosion can occurat a high rate,it is important that a means be available to alertthe user of products or equipment that involve the use ofdissimilar metal combinations in an electrolyte
11、of the possibleeffects of galvanic corrosion.4.2 One method that is used to predict the effects of galvaniccorrosion is to develop a galvanic series by arranging a list ofthe materials of interest in order of observed corrosion poten-tials in the environment and conditions of interest.The metalthat
12、will suffer increased corrosion in a galvanic couple in thatenvironment can then be predicted from the relative position ofthe two metals in the series.4.3 Types of Galvanic Series:4.3.1 One type of Galvanic Series lists the metals of interestin order of their corrosion potentials,starting with the
13、mostactive(electronegative)and proceeding in order to the most1This guide is under the jurisdiction of ASTM Committee G01 on Corrosion ofMetalsand is the direct responsibility of Subcommittee G01.11 on ElectrochemicalMeasurements in Corrosion Testing.Current edition approved May 1,2014.Published May
14、 2014.Originallyapproved in 1983.Last previous edition approved in 2009 as G8298(2009).DOI:10.1520/G0082-98R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standa
15、rds Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 noble(electropositive).The potentials themselves(versus anapp
16、ropriate reference half-cell)are listed so that the potentialdifference between metals in the series can be determined.Thistype of Galvanic Series has been put in graphical form as aseries of bars displaying the range of potentials exhibited bythe metal listed opposite each bar.Such a series is illustrated inFig.1.NOTE1Dark boxes indicate active behavior of active-passive alloys.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 30C(Redrawn fro