ASTM B63-07(2013)
(Test Method)Standard Test Method for Resistivity of Metallically Conducting Resistance and Contact Materials
Standard Test Method for Resistivity of Metallically Conducting Resistance and<brk/> Contact Materials
SIGNIFICANCE AND USE
4.1 In the case of materials for resistors and heating elements, a knowledge of resistivity is important in determining whether wire or strip of a specified area of cross section and length will have a required resistance. It serves as one basis for the selection of materials for specific applications and its measurement is a necessary acceptance test for resistance materials.
4.2 In the case of materials for electrical contacts, the measurement of resistivity can serve as a test for uniformity of materials of nominally the same composition and structure.
SCOPE
1.1 This test method covers the determination, to a precision of 2 %, of the electrical resistivity of materials used in resistors, heating elements, and electrical contacts, as well as products of powder metallurgy processes which are used for other purposes. Note 1—For determining the resistivity of electrical conductors, see Test Method B193.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: B63 − 07 (Reapproved 2013)
Standard Test Method for
Resistivity of Metallically Conducting Resistance and
Contact Materials
This standard is issued under the fixed designation B63; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) 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. Scope ρ 5 RA/L (1)
1.1 Thistestmethodcoversthedetermination,toaprecision
where R is the resistance in ohms of a specimen of the
of 2 %, of the electrical resistivity of materials used in
material of uniform cross section A and of a length L.In
resistors, heating elements, and electrical contacts, as well as
reporting values of resistivity under this test A shall be ex-
products of powder metallurgy processes which are used for
pressed in square centimeters and L in centimeters. Resistiv-
other purposes.
ity is measured in micro ohm-meter. English units of ohms
circular mil per foot are expressed as:
NOTE 1—For determining the resistivity of electrical conductors, see
Test Method B193.
ρ 5 12 310 RA/0.7854 L (2)
1.2 The values stated in inch-pound units are to be regarded
where:
as standard. The values given in parentheses are mathematical
R = resistance in ohms
conversions to SI units that are provided for information only
A = uniform cross section area in square inches
and are not considered standard.
L = length in inches
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar
4.1 In the case of materials for resistors and heating
with all hazards including those identified in the appropriate
elements, a knowledge of resistivity is important in determin-
Material Safety Data Sheet (MSDS) for this product/material
ingwhetherwireorstripofaspecifiedareaofcrosssectionand
as provided by the manufacturer, to establish appropriate
length will have a required resistance. It serves as one basis for
safety and health practices, and determine the applicability of
the selection of materials for specific applications and its
regulatory limitations prior to use.
measurement is a necessary acceptance test for resistance
materials.
2. Referenced Documents
4.2 In the case of materials for electrical contacts, the
2.1 ASTM Standards:
measurement of resistivity can serve as a test for uniformity of
B193 Test Method for Resistivity of Electrical Conductor
materials of nominally the same composition and structure.
Materials
5. Apparatus
3. Terminology
5.1 Means for applying current and voltage terminals to the
3.1 Definitions:
specimen are specified in Section 9. An optional suitable
3.1.1 resistivity, n—that property of a material which deter-
specimen holder for nonductile materials is shown in Fig. 1.
mines its resistance to the flow of an electric current, expressed
as: 5.2 A suitable bridge, potentiometer, digital ohmmeter, or
equivalent, with necessary accessories for making resistance
measurements with a limit of error of less than 0.5 %.
This test method is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
5.3 Means for measuring the dimensions of the specimen,
B02.10 on Thermostat Metals and Electrical Resistance Heating Materials.
adequate to determine its length and its mean area of cross
Current edition approved May 1, 2013. Published May 2013. Originally
section, each within 0.5 %.
approved in 1926. Last previous edition approved in 2007 as B63 – 07. DOI:
10.1520/B0063-07R13.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Test Specimen
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Ductile Materials—The test specimen for ductile
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. materials, including those used for contacts, shall be in the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B63 − 07 (2013)
Description Dimensions, in. (mm) Material Number
Item
Required
1 Base block ⁄2 by 3 by 4 (12.7 by 76.2 by 101.6) micarta 1
2 Clamp block ⁄4 by 1 by 1 (19.0 by 25.4 by 25.4) copper 2
10 3
3 Current lead clamp screw, knurled head ⁄32 by ⁄16 brass 2
4 Specimen clamp screw, knurled head ⁄4in.by40by1in. brass 2
1 15 7
5 Pivot bracket ⁄2 by ⁄16 by 1 ⁄16 (12.7 by 23.8 by 36.5) steel 2
6 Pivot . steel 2
1 3
7 Pivot block ⁄2 by 2 ⁄32 by 3 (12.7 by 53.2 by 76.2) micarta 1
8 Potential knife-edge . steel 2 sets
9 Specimen being tested . . .
NOTE 1—Contact surfaces must be clean and free of visible oxide.
FIG. 1 Specimen Holder for Nonductile Materials
form of a wire or a strip. In order to determine the resistivity material is readily machinable. For materials which are not
with a precision of 2 %, it is necessary that the resistance, readily machinable, such as those containing graphite, a flat
cross-sectional area, and length shall be measured with a limit strip may be used as a test specimen. In order to determine the
of error within 0.5 %. To ensure this limit of error each test resistivity with a precision of 2 %, each specimen shall
specimen shall conform to the following: conform to the following:
6.1.1 It shall have a length of at least 0.5 ft (15 cm) between 6.2.1 The diameter of a specimen (Fig. 2), or the thickness
potential probes. and width of a strip specimen, shall be uniform within 1 %.
6.1.2 It shall have a resistance of at least 0.001 Ω. 6.2.2 It shall show no surface cracks or other defects
6.1.3 If the cross section is to be determined by direct observable with normal vision, and shall be free from surface
measurement, the diameter of a wire specimen or the thickness oxide.
of a strip specimen shall not be less than the limits defined by
the 0.5 % criteria of 6.1, and this dimension throughout the 7. Length Measurements
length of the specimen shall not vary by more than 3 %.
7.1 The length may be measured by any scale which will
6.1.4 It shall show no surface cracks or other defects
give an accuracy of 0.5 % in the length measured. In case
observable with normal vision, and shall be free from surface
potential leads are used, the length shall be taken between the
oxide.
potential contacts. In the direction of the length of specimen,
6.2 Nonductile Materials—Thetestspecimenfornonductile the dimension of each potential contact, including soldering
materials shall be made in accordance with Fig. 2 if the surface or clamp contact area, shall not be more than 0.5 % of
B63 − 07 (2013)
E = weight of specimen in water, g
The cross-sectional area, A, in square centimeters, may be
found from the equation:
A 5 ~B 2 E!/L (4)
8.3.2 For porous materials such as products of powder
metallurgy, weigh a specimen of at least 10 g in air. Immerse
the specimen for at least4hinoil (viscosity of approximately
200 SUS at 37.8°C (100°F), held at a temperat
...
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