作者:标准资料网 时间:2024-05-18 12:42:32   浏览:9255   来源:标准资料网

【英文标准名称】:StandardPracticeforDiscontinuity(Holiday)TestingofNonconductiveProtectiveCoatingonMetallicSubstrates
【原文标准名称】:金属衬底上非传导保护涂料的间断性(假期)检验标准实施规程
【标准号】:ASTMD5162-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【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】:D01.46
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:discontinuity;highvoltage;holiday;holidaydetectors;lowvoltage;newlinings;sparktesters;wetspongetypeinstruments;Discontinuities--coatings;Electricalmeasurements--coatingapplications;Substrates--coatingapplications;Substrates--metalli
【摘要】:Acoatingisappliedtoametallicsubstratetopreventcorrosion,reduceabrasionorreduceproductcontamination,orallthree.Thedegreeofcoatingcontinuityrequiredisdictatedbyserviceconditions.Discontinuitiesinacoatingarefrequentlyveryminuteandnotreadilyvisible.Thispracticeprovidesaprocedureforelectricaldetectionofminutediscontinuitiesinnonconductivecoatingsystems.Electricaltestingtodeterminethepresenceandnumberofdiscontinuitiesinacoatingfilmisperformedonanonconductivecoatingappliedtoanelectricallyconductivesurface.Theallowablenumberofdiscontinuitiesshouldbedeterminedpriortoconductingthistestsincetheacceptablequantityofdiscontinuitieswillvarydependingoncoatingfilmthickness,design,andserviceconditions.Thelowvoltagewetspongetestequipmentisgenerallyusedfordeterminingtheexistenceofdiscontinuitiesincoatingfilmshavingatotalthicknessof0.5mm(20mil)orless.Highvoltagesparktestequipmentisgenerallyusedfordeterminingtheexistencesofdiscontinuitiesincoatingfilmshavingatotalthicknessofgreaterthan0.5mm(20mil).Coatingsthatareappliedatathicknessoflessthan0.5mm(20mil)maybesusceptibletodamageiftestedwithhighvoltagesparktestingequipment.Consultthecoatingmanufacturerforpropertestequipmentandinspectionvoltages.Topreventdamagetoacoatingfilmwhenusinghighvoltagetestinstrumentation,totalfilmthicknessanddielectricstrengthinacoatingsystemshallbeconsideredinselectingtheappropriatevoltagefordetectionofdiscontinuities.Atmosphericconditionsshallalsobeconsideredsincethevoltagerequiredforthesparktogapagivendistanceinairvarieswiththeconductivityoftheairatthetimethetestisconducted.SuggestedstartingvoltagesareprovidedinTable1.Thecoatingmanufacturershallbeconsultedtoobtainthefollowinginformation,whichwouldaffecttheaccuracyofthistesttodeterminediscontinuities:Establishthelengthoftimerequiredtoadequatelydryorcuretheappliedcoatingfilmpriortotesting.Solventsretainedinanuncuredcoatingfilmmayformanelectricallyconductivepaththroughthefilmtothesubstrate.Determinewhetherthecoatingcontainselectricallyconductivefillersorpigmentsthatmayaffectthenormaldielectricproperties.Thispracticeisintendedforusewithnewliningsappliedtometalsubstrates.Itsuseonacoatingpreviouslyexposedtoanimmersionconditionhasoftenresultedindamagetothecoatingandhasproducederroneousdetectionofdiscontinuitiesduetopermeationormoistureabsorptionofthecoating.Depositsmayalsobepresentonthesurfacecausingtelegraphing(currenttravelingthroughamoisturepathtoadiscontinuity,givinganerroneousindication)orcurrentleakageacrossthesurfaceofthecoatingduetocontamination.Theuseofahighvoltagetesteronpreviouslyexposedcoatingshastobecarefullyconsideredbecauseofpossiblespark-through,whichwilldamageanotherwisesoundcoating.Althoughalowvoltagetestercanbeusedwithoutdamagingthecoating,itmayalsoproduceerroneousresults.1.1Thispracticecoversproceduresfordeterminingdiscontinuitiesusingtwotypesoftestequipment:1.1.1TestMethodA8212;LowVoltageWetSponge,and1.1.2TestMethodB8212;HighVoltageSparkTesters.1.2Thispracticeaddressesmetallicsubstrates.Forconcretesurfaces,refertoPracticeD4787.1.3ThevaluesstatedinSIunitsaretoreregardedasthestandard.Thevaluesgiveninparentheses......
【中国标准分类号】:A29
【国际标准分类号】:25_220_20
【页数】:5P.;A4
【正文语种】:英语