ASTM B 368-2003

ThisdocumentisnotanASTMstandardandisintendedonlytoprovidetheuserofanASTMste

itmaynotbetechnicallypossibletoadequatelydepictallchangesaccurately,asesonlythecurrentversion

ofthestandardaspublishedbyASTMistobeconsideredtheofficialdocument.

Designation:B368–97(Reapproved2003)

e1

StandardTestMethodfor

Copper-AcceleratedAceticAcid-SaltSpray(Fog)Testing

(CASSTest)

1

ThisstandardisissuedunderthefixeddesignationB368;thenumberimmediatelyfollowingthedesignationindicatestheyearof

originaladoptionor,inthecaseofrevision,rinparenthesesindicatestheyearoflastreapproval.A

superscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.

ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.

e

1

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—Sections8.1and10.1.12wereeditoriallyupdatedinJuly2003.

1.1Thismethodprescribestheconditionsrequiredincopper-acceleratedaceticacid-saltspray(CASS)testingforspecification

ndarddoesnotspecifythetypeoftestspecimenorexposureperiodstobeusedforaspecificproduct,northe

interpretationtobegiventotheresults.

1.2Thismethodisapplicabletoevaluatingthecorrosiveperformanceofdecorativecopper/nickel/chromiumornickel/

chromiumcoatingsonsteel,zincalloys,aluminumalloys,soapplicabletothe

tabilityofthistestandcorrelationofresultswithserviceexperienceshouldbedetermined

beforeitisspecifiedforcoatingsystemsormaterialsotherthanthosementionedinthisparagraph.

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1—ereferencedforinformationonly:PracticesB537andE50,SpecificationsB456and

B604,andTestMethodB602.

1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,eresponsibility

oftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatory

especificsafetyprecautionaryinformationsee8.1.1.8.1.

ncedDocuments

2.1ASTMStandards:

B117PracticeforOperatingSaltSpray(Fog)Apparatus

2

ThismethodisunderthejurisdictionofASTMCommitteeB-8B08onMetallicandInorganicCoatingsandisthedirectresponsibilityofSubcommitteeB08.10on

GeneralTestMethods.

10,allypublishedasB368–eviousedition

B368–85(1997).approvedin1997asB368–97.

TheCASStestwasdevelopedbytheinitiativeoftheResearchBoardoftheAmericanElectroplatersSocietyunderAESProject15.

1

Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.

1

B162SpecificationforNickelPlate,Sheet,andStrip

3

B456SpecificationforElectrodepositedCoatingsofCopperPlusNickelPlusChromiumandNickelPlusChromium

4

B537PracticeforRatingofElectroplatedPanelsSubjectedtoAtmosphericExposure

4

B602TestMethodforAttributeSamplingofMetallicandInorganicCoatings

4

B604SpecificationforDecorativeElectroplatedCoatingsofCopper/PlusNickel/PlusChromiumonPlastics

4

D1193SpecificationforReagentWater

5

E50PracticesforApparatus,Reagents,andSafetyPrecautionsConsiderationsforChemicalAnalysisofMetals,Ores,and

RelatedMaterials

6

ficanceandUse

3.1TheCASStestiswidelyemployedandisusefulforspecificationacceptance,simulatedserviceevaluation,manufacturing

control,evelopedspecificallyforusewithdecorative,electrodepositednickel/chromium

andcopper/nickel/hetesthasimprovedthequalityofelectroplatedpartsandledtothedevelopment

ofnewandsuperiorelectroplatingprocesses.

tus

4.1TheapparatusrequiredfortheCASStestconsistsofafogchamber,asalt-solutionreservoir,asupplyofcompressedair,

oneormoreatomizingnozzles,specimensupports,provisionforheatingthechamber,andnecessarymeansofcontrol.

4.2Thesizeanddetailedconstructionoftheapparatusareoptional,providedtheconditionsmeettherequirementsofthis

CASStest,however,the

requirementsforairpressureandtemperaturearetypically0.08to0.12MPaand60to65°C,ualairpressure

willbethatrequiredtoproducethepropercollectionrate(see8.3.1).

4.3Theapparatusshallbeconstructedsothatdropsofsolutionthataccumulateontheceilingorcoverofthechamberdonot

fsolutionthatfallfromthespecimensshallnotbereturnedtothesolutionreservoir

forrespraying.

4.4Materialsofconstructionshallnotaffectthecorrosivenessofthefog,norbethemselvescorrodedbythefog.

lution

5.1Preparethesaltsolutionbydissolving5partsbyweightofsaltin95partsofwaterconformingtoSpecificationD1193,

tshallbesodiumchloride(NaCl),ACSreagentgrade,fthissolutionshallbebetween6.0

tiesorcontam-inationofeitherthesaltorthewater,orboth,shouldbesuspectedifthepHisoutsideofthisrange

(Note2).

5.2Add0.25gofreagentgradecopperchloride(CuCl

2

·2H

2

O)toeachlitreofthesaltsolution;dissolveandmixthoroughly.

5.3ThepHofthesalt-coppersolutionshallbeadjustedtotherangeof3.1to3.3,asmeasuredonasampleofthecollected

spray,bytheadditionofglacialaceticacid,ACSreagentgrade,orequivalent(Note3).ThepHmeasurementshallbemade

electrometricallyat25°thesolutionisatomized,itshallbefreeofsuspendedsolids(Note4).

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2—Asolutionhavingaspecificgravityof1.030to1.040,whenmeasuredatatemperatureof25°C,willmeettheconcentrationrequirement.

Itissuggestedthatadailycheckbemade.

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3—TheinitialsolutionmaybeadjustedtoapHof3.0to3.1,withtheexceptionthatthepHofthecollectedfogwillbewithinthespecified

mentoftheinitialpHformakeupsolutionisbasedthan

1.3ormorethan1.6mLoftheglacialaceticacidarerequiredperlitreofsodiumchlorideandcoppersolutiontoattainthespecifiedpH,somediscrepancy

inthesystemmaybesuspected(thepurityofthewaterorsalt,orboth;theaccuracyofthepHmeter;thegeneralcleanlinessofthesystem;etc.).

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4—Thefreshlypreparedsaltsolutionmaybefilteredordecantedbeforeitisplacedinthereservoir,ortheendofthetubeleadingfromthe

solutiontotheatomizermaybecoveredwithadoublelayerofcheeseclothtopreventpluggingofthenozzle.

ply

6.1Thecompressedairsupplytothenozzleornozzlesforatomizingthetestsolutionshallbefreeofoilanddirt(Note5).

Pressureshallbeadequatetoprovideaspecifireof0.1060.02MPahasbeenfoundsatisfactory(Note

6).

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5—Theairsupplycanbefreedofoilanddirtbypassingitthroughawaterscrubberoratleast60cmofsuitablecleaningmaterial,suchassheep’s

wool,excelsior,slagwool,cialfiltersforcompressedairmaybeused.

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6—Atomizingnozzlesmayhaveacriticalpressure,ritical

pressureofanozzlehasnotbeendeterminedwithcertainty,controloffluctuationintheairpressurewithin60.0007MPabyinstallingapressureregulator

valveminimizesthepossibilitythatthenozzlewillbeoperatedatitscriticalpressure.

2

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ecimens

7.1Thetypeandnumberoftestspecimenstobeused,aswellasthecriteriafortheevaluationofthetestresults,shallbedefined

inthespecificationscoveringthematerialorproductbeingtestedorshallbemutuallyagreeduponbetweenthepurchaserandthe

supplier.

ure

8.1PreparationofTestSpecimens—otherwiseagreedupon,clean

decorativecopper/nickel/chromiumornickel/chromiumcoatingsimmediatelybeforetestingbywipingsignificantsurfaceswith

acottonpadsaturatedwithaslurrycontaining10gofpuremagnesiumoxidepowder(ACSreagentgrade)in100mLofdistilled

nsinginwarmrunningwater,edaluminumpartsmay

becleanedwithinhibited1,1,1-trichloroethaneorothersuitableorganicsolvent(see8.1.1).Warning).Donotcleanorganicand

ethodsofcleaning,suchastheuseofanitric-acidsolutionforthechemicalcleaning

orpassivationofstainlesssteelspecimens,re

thatthespecimentthecutedgesofplated,coated,

ormultilayeredmaterialsandareascontainingidentificationmarksorincontactwiththeracksorsupportswithacoatingthatis

stableundertheconditionsofthetest,suchaswax,stop-offlacquer,orpressure-sensitivetape.

8.1.1Caution—1,1,1-Trichloroethanetape.(Warning—1,1,1-Trichloroethaneshouldbeusedinawell-ventilatedareaaway

fromopenflames.)

8.2PositioningofSpecimens—PositionthespecimensintheCASStestchamberduringthetestsothatthefollowingconditions

aremet:

8.2.1Supportorsuspendthespecimens1562°fromtheverticalandpreferablyparalleltotheprincipaldirectionofhorizontal

flowoffogthroughthechamber,torsuspendautomobileparts,however,

soastoexposeallsignifiositionontheautomobileisvertical,

placethepartinaninclineposition15°ositionontheautomobile

isfacingdown,rotatethepartapproximately180°totestthesignifieareseveralsignificantsurfacesatdifferent

angles,exposeeachsurfaceofoneormorespecimens.

8.2.2Makesurethespecimensdonotcomeincontactwitheachotheroranyothermetallicmaterialoranymaterialcapable

ofactingasawick.

8.2.3Placeeachspecimensoastopermitfreesettlingoffogonallspecimens.

8.2.4Makesurethesaltsolutionfromonespecimendoesnotdriponanyotherspecimen.

8.2.5Placethespecimensinthechamberjustpriortobringingthetestchambertotherequiredtemperatureandturningonthe

air,sincestorageinanidlechamberovernight,orforothersignificantlengthoftime,canaffecttestresults.

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7—Suitablematerialsfortheconstructionorcoatingofracksandsupportsareglass,rubber,plastic,talshould

dwoodenstripsaresuitableforthesupportofflsion

fromglasshooksorwaxedstringmaybeusedaslongasthespecifissary,suchsuspensionmaybemade

bymeansofsecondarysupportatthebottomofthespecimens.

8.3ConditionsintheSalt-SprayChamber—MaintaintheexposurezoneoftheCASStestchamberatatemperatureof4961°C

duringtheexposureperiod(Note8).Afterclosingthetestchamber,bringthetemperatureto49°

testdurationshallcommencewhenthetemperatureis4961°eairsupplybypassing

finebubblesthroughheateddistilledordeionizedwater(seeSpecificationD1193,TypeIV)sothatthetemperatureoftheairafter

expansionatthenozzleis4961°thetemperaturewithintheexposurezoneoftheclosedcabinet(Note9)twiceaday

atleast7hapart(exceptSaturdays,Sundays,andholidays,whenthesalt-spraytestisnotinterruptedforexposing,rearranging,

orremovingtestspecimensortocheckandreplenishthesolutioninthereservoir).

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8—Thiscanbebestaccomplishedbypreheatingthechamberto49°Cbeforestartingsolutionatomization.

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9—Asuitablemethodtorecordthetempordedtemperature

mustbeobtainedwiththesalt-spraychamberclosedtoavoidafalselowreading,ticcontrol

oftemperatureinthechamberandacontinuousrecordoftemperaturearedesirable.

8.3.1Placeatleasttwocleanfogcollectorswithintheexposurezonesothatnodropsofsolutionwillbecollectedfromthe

onthecollectorsintheproximityofthetestspecimens,onenearesttoanynozzleand

rethatthefogissuchthatforeach80cm

2

ofhorizontalcollectingareaeachcollectorcollectsfrom1.0to2.0mL/hofsolution,basedonatypicalrunofatleast22h(Note

10).Maintainthesodiumchlorideconcentrationofthecollectedsolutionbetween4.5and5.5mass%(Note11andNote12).

Dilutionandevaporationofcondensateshouldbeavoided(Note13).

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10—Suitablecollectingdevicesareglassfswithadiameterof

10cm(areaofabout80cm

2

)and50-mLcylindersarepreferred.

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11—Asolutionhavingaspecificgravityoffrom1.030to1.040,whenmeasuredat25°C,

concentrationmayalsobedeterminedasfollows:Dilute5mLofthecollectedsolutionto100mLwithdistilledwaterandmixthoroughly;pipeta10-mL

aliquotintoanevaporatingdishorcasserole;add40mLofdistilledwaterand1mLof1%potassiumchromate(K

2

CrO

4

)(ACSreagentgradewithless

FIG.1ArrangementofFogCollectors

than0.005%chloride)andtitratewith0.1Nsilvernitrate(AgNO

3

)(ACSreagentgrade)solutiontothefirstappearanceofapersistentredcoloration.

Atestsolutionthatrequiresbetween3.9and4.9mLof0.1NAgNO

3

solutionwillmeettheconcentrationrequirements.

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12—Ithasnotbeenfoundnecessarytocheckcopperconcentrationofthecollectedsolution.

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13—Factorsthatmaycontributetodilutionandevaporationofcondensateandmakeitdifficulttocontroltheconcentrationarelower

temperature,inadequatecoverinsulation,andprolongedstorageoftestsolutionataboveroomtemperature.

8.3.2Directorbafflethenozzleornozzlessothatnoneofthespraycanimpingedirectlyonthetestspecimens.

8.4ContinuityofTest—Unlessotherwisespecifiedinthespecificationcoveringthematerialorproductbeingtested,thetest

uousoperationimpliesthatthechamberbeclosedandthespray

operatingcontinuously,exceptfortheshortdailyinterruptionsnecessarytoinspect,rearrange,orremovetestspecimens,tocheck

andreplenishthesolutioninthereservoir,leoperationssothatthese

interruptionsareheldtoaminimum.

8.5PeriodofTest—Designatetheperiodoftestbythespecificationscoveringthematerialorproductbeingtestedoras

mutuallyagreeduponbetweenthepurchaserandthesupplier.

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14—Typicalexposureperiodsare:6,16,22,48,96,192,240,504,and720h.

8.6CleaningTestedSpecimens—Unlessspecifiedinthespecificationscoveringthematerialorproductbeingtested,carefully

removespecimensattheendofthetest,rinsegentlyinclean,running,warmwater(38°C,max)toremovesaltdepositsfromtheir

surfaces,hespecimensuseastreamofclean,compressedairat0.25to0.30MPagagepressure.

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15—Ifsteelpartsarerinsedimmediatelyafterremovalfromthetestchamber,smallrustspotsorflakesofrustmayliftoffandberinsedaway.

,afterremovalfromthetestchamber,thepartisallowedtodry30to60minbeforerinsing,all

tdoesnotapplytozinc-diecastings.

8.7CalibrationofCorrosiveConditions—Thisprocedureforcalibrationandstandardizationofthecorrosiveconditionswithin

thecabinetinvolvesexposureofnickeltestpanelsanddeterminationoftheirmasslossinaspecifiy

bedonemonthlyormorefrequentlytomakesurethecabinetisoperatingwithinthelimitsspecifiedin8.7.4.

8.7.1Usenickelpanelsthatare7.5by10cm,approximately0.09cmthick,andmadefromthehighercarbongrade(0.15%

max)giveninSpecificationB162.

8.7.2Placeoneweighednickeltestpanelineachcornerofthecabinetwiththe10-cmlengthinclined30°totheverticalusing

rtestpanelsshouldbeontheinboardsideofthecondensatecollectors

rethetopofthepanelsareatthesamelevelasthetopofthecondensatecollectors.

8.7.3Exposethetestpanelsto22hofCASStesting,

thepanelsfromthecabinetandrinseeachinreagentgradewater(seeSpecificationD1193,TypeIV)eeach

panelin20%byvolumehydrochloricacidpreparedwithdistilledwaterfor2minat20to25°Cusingnickel-copperalloy400

(UNSN04400)gsmaybenonmetallicoranothermaterialthatwillnotaffectthemasslossofthenickelbygalvanic

achpanelinwateratroomtemperatureandtheninwarm(38°C)flelsinanovenat100°C

hepanelstoreachroomtemperatureandweighimmediatelyonananalyticalbalance.

8.7.4Determinethemasslossofeinethe

corrosivelossbydividingthemasslossbytheareaofonefaceofthetestpanel(77.5cm

2

).Thecorrosiverateshallbe0.45to

0.85mg/cm

2

tosatisfytherequirementsofthismethod.

tionofResults

9.1Acarefulandimmediateexaminationshallbemadefortheextentofcorrosionofthedry-testspecimens;orforotherfailure,

asrequiredbythespecificationscoveringthematerialorproductbeingtested;orbyagreementbetweenthepurchaserandthe

supplier.

sandReports

10.1Thefollowinginformationshallberecorded,unlessotherwiseprescribedinthespecificationscoveringthematerialor

productbeingtested:

10.1.1Thetitle,designationandyearofissueofthismethod.

10.1.2Thesalt,water,copperchloride,andaceticacidusedinpreparingthesaltsolution,

10.1.3Allreadingsoftemperaturewithintheexposurezoneofthechamber,

10.1.4Dailyrecordsofdataobtainedfromeachfogcollectingdevice,includingthefollowing:

10.1.4.1Volumeofsaltsolutioncollectedin(mL/h)/8cm

2

,

10.1.4.2Concentrationorspecificgravityat25°Cofsolutioncollected,and

10.1.4.3pHofsolutioncollected,

10.1.5Nickelpanelcorrosionratecalibration,

10.1.6Typeofspecimenanditsdimensions,ornumber,ordescriptionofpart,

10.1.7Methodofcleaningspecimens,

10.1.8Methodofsupportingorsuspendingthearticleinthesalt-spraychamber,

10.1.9Descriptionofprotectionusedasrequiredin8.1,

10.1.10Exposureperiod,

10.1.11Interruptionsinthetest,causeandlengthoftime,and

10.1.12Resultsofinspections.

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16—Ifanyoftheatomizedsaltsolutionthathasnotcomeincontactwiththetestspecimensisreturnedtothereservoir,itisadvisabletorecord

theconcentrationorspecificgravityandthepHofthissolutionalso.

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17—Roundrobintestingrevealertestingisongoingtoclarify

therootcauses.

ionandBias

11.1Thereliability,reproducibility,andaccuracyoftheCASStestdependsonproperandconsistentcontrolofanumberof

factors,including:

11.1.1Cleaningofthetestsamples,

11.1.2Positioningofthespecimensandsamplesinthetestcabinet,

11.1.3Rateofcondensationwithinthetestcabinet,

11.1.4CASSsolutionmakeup,

11.1.5Cabinetmaintenance,and

11.1.6Calibrationofcorrosiveconditions.

11.2TheprecisionandbiasoftheCASStestisbeingdeterminedandwillincludestudyofthereproducibilityofthecalibration

proceduredescribedin8.7.

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