ASTM B667-97(2009)
(Practice)Standard Practice for Construction and Use of a Probe for Measuring Electrical Contact Resistance
Standard Practice for Construction and Use of a Probe for Measuring Electrical Contact Resistance
SIGNIFICANCE AND USE
Electrical contact resistance is an important characteristic of the contact in certain components, such as connectors, switches, slip rings, and relays. Ordinarily, contact resistance is required to be low and stable for proper functioning of many devices or apparatus in which the component is used. It is more convenient to determine contact resistance with a probe than to incorporate the contact material into an actual component for the purpose of measurement. However, if the probe contact material is different from that employed in the component, the results obtained may not be applicable to the device.
Information on contact resistance is useful in materials development, in failure analysis studies, in the manufacturing and quality control of contact devices, and in research.
Contact resistance is not a unique single-valued property of a material. It is affected by the mechanical conditions of the contact, the geometry and roughness of contacting surfaces, surface cleanliness, and contact history, as well as by the material properties of hardness and conductivity of both contacting members. An objective of this practice is to define and control many of the known variables in such a way that valid comparisons of the contact properties of materials can be made.
In some techniques for measuring contact resistance it is not possible to eliminate bulk resistance, that is, the resistance of the metal pieces comprising the contact and the resistance of the wires and connections used to introduce the test current into the samples. In these cases, the measurement is actually of an overall resistance, which is often confused with contact resistance.
SCOPE
1.1 This practice describes equipment and techniques for measuring electrical contact resistance with a probe and the presentation of results.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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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Designation: B667 − 97 (Reapproved2009)
Standard Practice for
Construction and Use of a Probe for Measuring Electrical
1
Contact Resistance
This standard is issued under the fixed designation B667; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope they funnel through these tiny areas. If oxide films or other
insulating layers interfere with these metal-to-metal contacts,
1.1 This practice describes equipment and techniques for
the contact resistance will be higher than when such layers are
measuring electrical contact resistance with a probe and the
absent (see 4.4 for bulk resistance limitation).
presentation of results.
3.2.2 contact resistance probe, n—an apparatus for deter-
1.2 The values stated in SI units are to be regarded as
mining electrical contact resistance characteristics of a metal
standard. No other units of measurement are included in this
surface. Probe, in this instance, should be distinguished from
standard.
the classical tool whose function it is to touch or move an
1.3 This standard does not purport to address all of the
object.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar
4. Significance and Use
with all hazards including those identified in the appropriate
Material Safety Data Sheet (MSDS) for this product/material
4.1 Electrical contact resistance is an important characteris-
as provided by the manufacturer, to establish appropriate
tic of the contact in certain components, such as connectors,
safety and health practices, and determine the applicability of
switches,sliprings,andrelays.Ordinarily,contactresistanceis
regulatory limitations prior to use.
required to be low and stable for proper functioning of many
devicesorapparatusinwhichthecomponentisused.Itismore
2. Referenced Documents
convenient to determine contact resistance with a probe than to
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2.1 ASTM Standards:
incorporate the contact material into an actual component for
B542 Terminology Relating to Electrical Contacts and Their
the purpose of measurement. However, if the probe contact
Use
material is different from that employed in the component, the
results obtained may not be applicable to the device.
3. Terminology
4.2 Information on contact resistance is useful in materials
3.1 Definitions—Many terms used in this practice are de-
development, in failure analysis studies, in the manufacturing
fined in Terminology B542.
and quality control of contact devices, and in research.
3.2 Definitions of Terms Specific to This Standard:
4.3 Contactresistanceisnotauniquesingle-valuedproperty
3.2.1 contact resistance, n—the resistance to current flow
of a material. It is affected by the mechanical conditions of the
between two touching bodies, consisting of constriction resis-
contact, the geometry and roughness of contacting surfaces,
tance and film resistance.
surface cleanliness, and contact history, as well as by the
3.2.1.1 Discussion—Constrictionresistanceoriginatesinthe
material properties of hardness and conductivity of both
fact that mating surfaces touch in most cases at only their high
contacting members. An objective of this practice is to define
spots, which are often called“ asperities” or, more commonly,
and control many of the known variables in such a way that
a-spots. The current flow lines are then forced to constrict as
valid comparisons of the contact properties of materials can be
made.
1
This practice is under the jurisdiction ofASTM Committee B02 on Nonferrous
Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on
4.4 In some techniques for measuring contact resistance it is
Electrical Contact Test Methods.
not possible to eliminate bulk resistance, that is, the resistance
Current edition approved April 15, 2009. Published April 2009. Originally
ϵ1
of the metal pieces comprising the contact and the resistance of
approved in 1980. Last previous edition approved in 2003 as B667 – 97 (2003) .
DOI: 10.1520/B0667-97R09.
thewiresandconnectionsusedtointroducethetestcurrentinto
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the samples. In these cases, the measurement is actually of an
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
overall resistance, which is often confused with contact resis-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. tance.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation:B667–97(Reapproved2003) Designation:B667–97(Reapproved2009)
Standard Practice for
Construction and Use of a Probe for Measuring Electrical
1
Contact Resistance
This standard is issued under the fixed designation B 667; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
´ NOTE—Keywords were added editorially in December 2003.
1. Scope
1.1 This practice describes equipment and techniques for measuring electrical contact resistance with a probe and the
presentation of results.
1.2The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
2. Referenced Documents
2
2.1 ASTM Standards:
B 542 Terminology Relating to Electrical Contacts and Their Use
3. Terminology
3.1 Definitions—Many terms used in this practice are defined in Terminology B 542.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 contact resistancecontact resistance, n—the resistance to current flow between two touching bodies, consisting of
constriction resistance and film resistance.
3.2.1.1 Discussion—Constriction resistance originates in the fact that mating surfaces touch in most cases at only their high
spots, which are often called “ asperities” or, more commonly, a-spots. The current flow lines are then forced to constrict as they
funnel through these tiny areas. If oxide films or other insulating layers interfere with these metal-to-metal contacts, the contact
resistance will be higher than when such layers are absent (see 4.4 for bulk resistance limitation).
3.2.2 contact resistance probecontact resistance probe, n—an apparatus for determining electrical contact resistance charac-
teristics of a metal surface. Probe, in this instance, should be distinguished from the classical tool whose function it is to touch
or move an object.
4. Significance and Use
4.1 Electricalcontactresistanceisanimportantcharacteristicofthecontactincertaincomponents,suchasconnectors,switches,
slip rings, and relays. Ordinarily, contact resistance is required to be low and stable for proper functioning of many devices or
apparatus in which the component is used. It is more convenient to determine contact resistance with a probe than to incorporate
the contact material into an actual component for the purpose of measurement. However, if the probe contact material is different
from that employed in the component, the results obtained may not be applicable to the device.
4.2 Information on contact resistance is useful in materials development, in failure analysis studies, in the manufacturing and
quality control of contact devices, and in research.
4.3 Contact resistance is not a unique single-valued property of a material. It is affected by the mechanical conditions of the
contact, the geometry and roughness of contacting surfaces, surface cleanliness, and contact history, as well as by the material
1
This practice is under the jurisdiction ofASTM Committee B02 on Nonferrous Metals andAlloys and is the direct responsibility of Subcommittee B02.11 on Electrical
Contact Test Methods.
Current edition approved Dec. 9, 2003. Published December 2003. Originally approved in 1980. Last previous edition approved in 1997 as B667–97.
´1
Current edition approved April 15, 2009. Published April 2009. Originally approved in 1980. Last previous edition approved in 2003 as B 667 – 97 (2003) .
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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