ASTM G82-1998(2009) 预测电流腐蚀特性用电流系列的制定和使用的标准指南

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【英文标准名称】:StandardGuideforDevelopmentandUseofaGalvanicSeriesforPredictingGalvanicCorrosionPerformance
【原文标准名称】:预测电流腐蚀特性用电流系列的制定和使用的标准指南
【标准号】:ASTMG82-1998(2009)
【标准状态】:现行
【国别】:美国
【发布日期】:1998
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:G01.11
【标准类型】:(Guide)
【标准水平】:()
【中文主题词】:
【英文主题词】:active;corrosionpotential;galvaniccorrosion;GalvanicSeries;noble;passive;Acceleratedaging/testing--corrosion;Aluminum;Aluminumalloys--corrosiontesting;Austeniticsteel;Brass;Bronze;Cadmiummetals/alloys;Conductanceandconductivity(el
【摘要】:Whentwodissimilarmetalsinelectricalcontactareexposedtoacommonelectrolyte,oneofthemetalscanundergoincreasedcorrosionwhiletheothercanshowdecreasedcorrosion.Thistypeofacceleratedcorrosionisreferredtoasgalvaniccorrosion.Becausegalvaniccorrosioncanoccuratahighrate,itisimportantthatameansbeavailabletoalerttheuserofproductsorequipmentthatinvolvetheuseofdissimilarmetalcombinationsinanelectrolyteofthepossibleeffectsofgalvaniccorrosion.Onemethodthatisusedtopredicttheeffectsofgalvaniccorrosionistodevelopagalvanicseriesbyarrangingalistofthematerialsofinterestinorderofobservedcorrosionpotentialsintheenvironmentandconditionsofinterest.Themetalthatwillsufferincreasedcorrosioninagalvaniccoupleinthatenvironmentcanthenbepredictedfromtherelativepositionofthetwometalsintheseries.TypesofGalvanicSeries:OetypeofGalvanicSeriesliststhemetalsofinterestinorderoftheircorrosionpotentials,startingwiththemostactive(electronegative)andproceedinginordertothemostnoble(electropositive).Thepotentialsthemselves(versusanappropriatereferencehalf-cell)arelistedsothatthepotentialdifferencebetweenmetalsintheseriescanbedetermined.ThistypeofGalvanicSerieshasbeenputingraphicalformasaseriesofbarsdisplayingtherangeofpotentialsexhibitedbythemetallistedoppositeeachbar.SuchaseriesisillustratedinFig.1.Thesecondtypeofgalvanicseriesissimilartothefirstinthatitliststhemetalsofinterestinorderoftheircorrosionpotentials.Theactualpotentialsthemselvesarenotspecified,however.Thus,onlytherelativepositionofmaterialsintheseriesisknownandnotthemagnitudeoftheirpotentialdifference.SuchaseriesisshowninFig.2.UseofaGalvanicSeries:Generally,uponcouplingtwometalsintheGalvanicSeries,themoreactive(electronegative)metalwillhaveatendencytoundergoincreasedcorrosionwhilethemorenoble(electropositive)metalwillhaveatendencytoundergoreducedcorrosion.Usually,thefurtheraparttwometalsareintheseries,andthusthegreaterthepotentialdifferencebetweenthem,thegreateristhedrivingforceforgalvaniccorrosion.Allotherfactorsbeingequal,andsubjecttotheprecautionsinSection5,thisincreaseddrivingforcefrequently,althoughnotalways,resultsinagreaterdegreeofgalvaniccorrosion.Note8212;Darkboxesindicateactivebehaviorofactive-passivealloys.FIG.1GalvanicSeriesofVariousMetalsinFlowingSeawaterat2.4to4.0m/sfor5to15Daysat5to30x00B0;C(RedrawnfromOriginal)(seeFootnote5)ACTIVEEND
Magnesium
(x2212;)
MagnesiumAlloys
x2191;
Zinc
brvbar;
GalvanizedSteel
brvbar;
Aluminum1100
brvbar;
Aluminum6053
brvbar;
Alclad