Designation:B714–82(Reapproved1997)e1StandardTestMethodforD-CCriticalCurrentofCompositeSuperconductors1ThisstandardisissuedunderthefixeddesignationB714;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.e1NOTE—EditorialchangesweremadethroughoutinMarch1997.1.Scope1.1Thistestmethodcoverstheprocedureforthedetermi-nationofthed-ccriticalcurrentofcompositesuperconductors.1.2Thismethodisintendedforusewithsuperconductorshavingacriticalcurrentoflessthan600Aundertestconditionsandatmagneticfieldsoflessthan0.8oftheuppercriticalmagneticfield.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.SpecifichazardstatementsaregiveninSection6.2.ReferencedDocuments2.1ASTMStandards:B713TerminologyRelatingtoSuperconductors23.Terminology3.1RefertoTerminologyB713forgeneralterminologyforthefieldofsuperconductivity.4.SummaryofTestMethod4.1Adirectcurrentisappliedtothesuperconductorspeci-menandthevoltagegeneratedalongasectionofthespecimenismeasured.Thecurrentisincreasedfromzeroandthevoltage-currentcharacteristicisgenerated.Thecriticalcurrentisdefinedasthecurrentatwhichaspecifiedelectricfieldisexceededinthespecimen.5.SignificanceandUse5.1Thecriticalcurrendsofcompositesuperconductorsareusedtoestablishdesignlimitsforapplicationsofsupercon-ductingwires.Theoperatingconditionsofsuperconductorsintheseapplicationsdeterminemuchoftheirbehaviorandtestsmadewiththismethodmaybeusedtoprovidepartoftheinformationneededtodeterminethesuitabilityofaspecificsuperconductor.5.2Resultsobtainedfromthismethodcanalsobeusedfordetectingchangesinthesuperconductingpropertiesofacompositesuperconductorduetoprocessingvariables,han-dling...
