1、Designation:B6307(Reapproved 2013)Standard Test Method forResistivity of Metallically Conducting Resistance andContact Materials1This standard is issued under the fixed designation B63;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,
2、the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the
3、determination,to a precisionof 2%,of the electrical resistivity of materials used inresistors,heating elements,and electrical contacts,as well asproducts of powder metallurgy processes which are used forother purposes.NOTE1For determining the resistivity of electrical conductors,seeTest Method B193.
4、1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associa
5、ted with its use.It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet(MSDS)for this product/materialas provided by the manufacturer,to establish appropriatesafety and health practices,and deter
6、mine the applicability ofregulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B193 Test Method for Resistivity of Electrical ConductorMaterials3.Terminology3.1 Definitions:3.1.1 resistivity,nthat property of a material which deter-mines its resistance to the flow of an elect
7、ric current,expressedas:5 RA/L(1)where R is the resistance in ohms of a specimen of thematerial of uniform cross section A and of a length L.Inreporting values of resistivity under this test A shall be ex-pressed in square centimeters and L in centimeters.Resistiv-ity is measured in micro ohm-meter.
8、English units of ohmscircular mil per foot are expressed as:5 123106R A/0.7854 L(2)where:R=resistance in ohmsA=uniform cross section area in square inchesL=length in inches4.Significance and Use4.1 In the case of materials for resistors and heatingelements,a knowledge of resistivity is important in
9、determin-ing whether wire or strip of a specified area of cross section andlength will have a required resistance.It serves as one basis forthe selection of materials for specific applications and itsmeasurement is a necessary acceptance test for resistancematerials.4.2 In the case of materials for
10、electrical contacts,themeasurement of resistivity can serve as a test for uniformity ofmaterials of nominally the same composition and structure.5.Apparatus5.1 Means for applying current and voltage terminals to thespecimen are specified in Section 9.An optional suitablespecimen holder for nonductil
11、e materials is shown in Fig.1.5.2 A suitable bridge,potentiometer,digital ohmmeter,orequivalent,with necessary accessories for making resistancemeasurements with a limit of error of less than 0.5%.5.3 Means for measuring the dimensions of the specimen,adequate to determine its length and its mean ar
12、ea of crosssection,each within 0.5%.6.Test Specimen6.1 Ductile MaterialsThe test specimen for ductilematerials,including those used for contacts,shall be in the1This test method is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of Subcomm
13、itteeB02.10 on Thermostat Metals and Electrical Resistance Heating Materials.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 1926.Last previous edition approved in 2007 as B63 07.DOI:10.1520/B0063-07R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,o
14、rcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 form of a wire or a stri
15、p.In order to determine the resistivitywith a precision of 2%,it is necessary that the resistance,cross-sectional area,and length shall be measured with a limitof error within 0.5%.To ensure this limit of error each testspecimen shall conform to the following:6.1.1 It shall have a length of at least
16、 0.5 ft(15 cm)betweenpotential probes.6.1.2 It shall have a resistance of at least 0.001.6.1.3 If the cross section is to be determined by directmeasurement,the diameter of a wire specimen or the thicknessof a strip specimen shall not be less than the limits defined bythe 0.5%criteria of 6.1,and this dimension throughout thelength of the specimen shall not vary by more than 3%.6.1.4 It shall show no surface cracks or other defectsobservable with normal vision,and shall be free from surfaceoxide.
