1、Designation:G6186(Reapproved 2014)Standard Test Method forConducting Cyclic Potentiodynamic PolarizationMeasurements for Localized Corrosion Susceptibility ofIron-,Nickel-,or Cobalt-Based Alloys1This standard is issued under the fixed designation G61;the number immediately following the designation
2、indicates the year of originaladoption or,in the case of 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 test method covers a procedure for conduct
3、ingcyclic potentiodynamic polarization measurements to deter-mine relative susceptibility to localized corrosion(pitting andcrevice corrosion)for iron-,nickel-,or cobalt-based alloys in achloride environment.This test method also describes anexperimental procedure which can be used to check onesexpe
4、rimental technique and instrumentation.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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
5、 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterG3 Practice for Conventions Applicable to ElectrochemicalMeasurements in Corr
6、osion TestingG5 Reference Test Method for Making PotentiodynamicAnodic Polarization Measurements2.2 ASTM Adjuncts:Standard Samples(set of two)33.Significance and Use3.1 An indication of the susceptibility to initiation of local-ized corrosion in this test method is given by the potential atwhich the
7、 anodic current increases rapidly.The more noble thispotential,obtained at a fixed scan rate in this test,the lesssusceptible is the alloy to initiation of localized corrosion.Theresults of this test are not intended to correlate in a quantitativemanner with the rate of propagation that one might ob
8、serve inservice when localized corrosion occurs.3.2 In general,once initiated,localized corrosion can propa-gate at some potential more electropositive than that at whichthe hysteresis loop is completed.In this test method,thepotential at which the hysteresis loop is completed is deter-mined at a fi
9、xed scan rate.In these cases,the more electro-positive the potential at which the hysteresis loop is completedthe less likely it is that localized corrosion will occur.3.3 If followed,this test method will provide cyclic poten-tiodynamic anodic polarization measurements that will repro-duce data dev
10、eloped at other times in other laboratories usingthis test method for the two specified alloys discussed in 3.4.The procedure is used for iron-,nickel-,or cobalt-based alloysin a chloride environment.3.4 A standard potentiodynamic polarization plot is in-cluded.These reference data are based on the
11、results from fivedifferent laboratories that followed the standard procedure,using specific alloys of Type 304 stainless steel,UNS S30400and Alloy C-276,UNS N10276.3Curves are included whichhave been constructed using statistical analysis to indicate theacceptable range of polarization curves.3.5 Th
12、e availability of a standard test method,standardmaterial,and standard plots should make it easy for aninvestigator to check his techniques to evaluate susceptibilityto localized corrosion.4.Apparatus4.1 The polarization cell should be similar to the onedescribed in Reference Test Method G5.Other po
13、larizationcells may be equally suitable.4.1.1 The cell should have a capacity of about 1 L andshould have suitable necks or seals to permit the introductionof electrodes,gas inlet and outlet tubes,and a thermometer.The Luggin probe-salt bridge separates the bulk solution fromthe saturated calomel re
14、ference electrode.The probe tip should1This test method is under the jurisdiction of ASTM Committee G01 onCorrosion of Metals and is the direct responsibility of Subcommittee G01.11 onElectrochemical Measurements in Corrosion Testing.Current edition approved May 1,2014.Published May 2014.Originallya
15、pproved in 1986.Last previous edition approved in 2009 as G61 86(2009).DOI:10.1520/G0061-86R14.2For 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 standards Document Sum
16、mary page onthe ASTM website.3Available from ASTM International Headquarters.Order Adjunct No.ADJG0061.Original adjunct produced before 1995.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 be adjustable so that it can be brought into close proximity withthe working electrode.4.2 Specimen Holder:4.2.1 Specimens should be mounted in a suitable holderdesigned for flat strip,exposing 1 cm2to the test solution(Fig.1).Such specimen holders