ASTM B826-2009 用电阻试样监测大气腐蚀试验的试验方法

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【英文标准名称】:StandardTestMethodforMonitoringAtmosphericCorrosionTestsbyElectricalResistanceProbes
【原文标准名称】:用电阻试样监测大气腐蚀试验的试验方法
【标准号】:ASTMB826-2009
【标准状态】:现行
【国别】:美国
【发布日期】:2009
【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】:B02.11
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:atmosphericcorrosionmonitor;atmosphericcorrosiontesting;corrosivitymonitor;electricalresistanceprobe;environmentaltest;mixedflowinggastest;resistancemonitorprobe;Atmosphericcorrosionanalysis;Corrosivegastesting;Corrosivitymonito
【摘要】:Corrosivitymonitoringoftestenvironmentsprovidesameanstomonitoranintegratedvalueoftestcorrosivitywhichcannotbeevaluatedfromtestparametersthemselves,suchastemperature,humidity,andgasconcentration.Assuchthemonitorvaluecanbeusedforspecificationpurposessuchastestvalidation.Electricalresistancemonitoringofconductorsexposedtocorrosivemediaisawell-establishedpractice.,,,Theresistancemethodassumesuniformcorrosionovertheentiresurfaceoftheexposedmetalconductorsegment.Localcorrosionsuchaspitting,crevice,orgrainboundarycorrosionmayprovideinvalidestimatesoftestcorrosivity.Markedchangesinslopeofthecurveofelectricalresistanceratioversustimemayindicateundesiredprocesseswhichcanbeduetodeficienciesinthetestatmosphereorinthemonitoritself.BecauseoflimitationsofthediffusionprocesswithinthecorrosionproductformedonthemetalconductorsegmentoftheRMprobewhenpassivatingcorrosionfilmsareformed,resistancemonitoringmaynotbeusefulfortestchambermonitoringpurposesforverylongtestexposures.ChambermonitoringisdependentondetectingchangesintherateofcorrosionoftheRMasanindicatorsignalthatspecifiedgasconcentrationsmustbereverified.However,lowcorrosionrateslimittheabsolutevalueoftherateofchangeofcorrosionratewithchangeoftestconditions;forparabolicfilmgrowthprocesses,thegrowthratedecreaseswithtimelimitingthesensitivityoftheRMatextendedtesttimes.SincecorrosionratecanbeacomplexfunctionoftestparametersinMFGtestswithanygivenmetalprimarilyresponsivetoasubsetofthegasesintheMFGenvironment,morethanonetypemetalresistanceprobeisrequiredinordertoassistinmaintenanceofrelativegasconcentrations.Forsuchtestspecifications,valuesofresistanceratiosmustbereferredtoratiosobtainedunderknowntestconditionsassuppliedbythetestspecifier.Informationrelatingtothesensitivityofvariousmetalstovariouscorrodantshasbeenpublished.,RMprobescanbeusefulfrom1%ofthicknessconsumedupwardto50%ofthicknessconsumedbythecorrosionfilmgrowth.Conductorthicknessesbetween25nmand0.2mmhavebeenreportedandcommonsizesareavailablecommercially.1.1Thistestmethodprovidesameansformonitoringcorrosivityofenvironmentalteststhatinvolveexposuretocorrosivegases.1.2Thistestmethodusesaresistancemonitor(RM)probefabricatedfromachosenmetalconductor,withoneconductorsegmentuncoveredtopermitexposureofthechosenmetalconductortothecorrosivegasmixtureandthesecondconductorsegmentcoveredtoprotectthemetalconductorofthissegmentfromdirectattackbythecorrosivegasmixture.Thecoveredconductorsegmentprovidesareferenceforevaluatingchangesintheuncoveredsegment.Theratiooftheresistanceoftheexposedsegmenttothatofthecoveredsegmentprovidesameasureoftheamountofmetalconductorthathasreactedwiththecorrosivegastestenvironmenttoformpoorlyconductingcorrosionproduct,thusprovidingameasureoftestcorrosivity.1.3Resistancemonitoringisapplicabletoabroadrangeoftestconditionsbyselectionoftheappropriatemetalconductorandinitialmetalthickness.1.4ThismethodissimilarinintenttoTestMethodsB808.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithits......
【中国标准分类号】:H25
【国际标准分类号】:77_060
【页数】:4P.;A4
【正文语种】:英语