ASTM B693-17(2022)

Standard Specification for Silver-Nickel Electrical Contact Materials

ABSTRACT
This specification covers electrical contact components made from silver-nickel by powder metallurgical procedures. This covers compositions within the silver-nickel system normally specified by users of electrical contacts. Chemical analysis shall be performed to evaluate material conformance to specified composition requirements. A representative sample of chips may be obtained by milling, drilling, or crushing with dry tools, (without lubrication). In order to obtain free chips, the parts selected for testing shall have the oil extracted, if necessary. Physical tests including microstructure shall be performed on a representative number of specimens.
SIGNIFICANCE AND USE
9.1 Proprietary methods for manufacture of these materials vary significantly among suppliers and these methods influence such properties as arc erosion, contact resistance, and the tendency to weld in service. Since the performance of contacts in a device depends on numerous factors outside the contact itself (opening speed, closing speed, contact pressure, contact bounce, environmental variations, assembly technique and variations, etc.), this specification cannot ensure performance control in the application. As part of the qualification on initial samples, it is recommended that the user functionally test the materials electrically for all devices applicable to the material's use. This specification provides a means for the contact manufacturer and contact user to reach agreement on the details of material to be supplied for a specific use and reasonable assurance that future lots will be similar in properties and microstructure to the initial test or sample contact supplied.
SCOPE
1.1 This specification covers electrical contact components made from silver nickel by powder metallurgical procedures.  
1.2 This specification covers compositions within the silver-nickel system normally specified by users of electrical contacts.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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 Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2022
• ICS: 77.120.99 - Other non-ferrous metals and their alloys
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.05 - Precious Metals and Electrical Contact Materials and Test Methods

Relations

• Refers: ASTM E18-18 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2018
• Refers: ASTM E18-17 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2017
• Refers: ASTM E18-12 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Dec-2012
• Refers: ASTM B476-01(2012) - Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
• Effective Date: 01-May-2012
• Refers: ASTM E18-11 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Nov-2011
• Refers: ASTM E384-10 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-Feb-2010
• Refers: ASTM E384-10e1 - Standard Test Method for Knoop and Vickers Hardness of Materials
• Effective Date: 01-Feb-2010
• Refers: ASTM E384-09 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-May-2009
• Refers: ASTM E18-08a - Standard Test Methods for Rockwell Hardness of Metallic Materials <a href="#fn00002"></a>
• Effective Date: 15-May-2008
• Refers: ASTM E384-08ae1 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Mar-2008
• Refers: ASTM E384-08a - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Mar-2008
• Refers: ASTM E18-08 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 15-Jan-2008
• Refers: ASTM E384-08 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-Jan-2008
• Refers: ASTM E384-07a - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Dec-2007
• Refers: ASTM E384-07 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-Jul-2007

Overview

ASTM B693-17(2022) - Standard Specification for Silver-Nickel Electrical Contact Materials establishes minimum requirements for electrical contact components manufactured from silver-nickel alloys using powder metallurgical processes. Developed by ASTM International, this standard defines typical material compositions, requisite physical and mechanical properties, and quality assurance protocols to ensure consistent manufacturing and reliable performance of electrical contact materials used in a wide array of electrical devices.

ASTM B693-17(2022) applies internationally and facilitates agreement between manufacturers and users regarding quality, composition, and suitability for application. The specification emphasizes the importance of mutually agreed test methods and recognizes the variability in manufacturing techniques among suppliers, each of which can influence the functional properties of finished contacts.

Key Topics

• Scope of Material: Applies specifically to electrical contacts made from the silver-nickel system using powder metallurgy, covering various compositions as required by users of electrical contacts.
• Material Requirements: Specifies limits for alloy composition and impurities, with agreed-upon testing and analytical procedures between manufacturer and purchaser.
• Physical and Mechanical Properties: Outlines qualification tests for density, hardness, tensile strength, and microstructure to ensure conformance to application-specific requirements.
• Sampling and Testing: Describes standardized procedures for taking representative samples for chemical and physical analysis, with special attention to oil extraction and chip preparation.
• Ordering Information: Requires purchase orders to include detailed information such as dimensions, chemical composition, mechanical and physical properties, and certification requirements.
• Inspection and Certification: Details conditions for material inspection, testing, certification, and reporting of test results.

Applications

Silver-nickel electrical contact materials specified by ASTM B693 are widely used in:

• Switchgear and Relay Contacts: Due to their superior electrical conductivity and resistance to arc erosion.
• Circuit Breakers: For reliable current carrying and interruption performance.
• Connectors and Terminals: Where low contact resistance and stable mechanical properties are required.
• Switches and Electrical Controls: In applications demanding a balance between conductivity, mechanical strength, and resistance to welding or deformation.
• Power Distribution Components: Such as industrial control panels and automotive electrical systems.

These materials are chosen for their combination of physical durability, electrical performance, and adaptability to custom compositions, making them integral to many high-performance and safety-critical electrical systems.

Related Standards

ASTM B693 references and is complemented by several related ASTM standards, including:

• ASTM B328 - Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings
• ASTM B476 - Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
• ASTM E18 - Test Methods for Rockwell Hardness of Metallic Materials
• ASTM E384 - Test Method for Microindentation Hardness of Materials

Additionally, adherence to best practices regarding safety, health, and environmental considerations is emphasized, requiring users to consult the relevant Safety Data Sheet (SDS) and abide by all applicable regulations.

Keywords: ASTM B693, silver-nickel contacts, electrical contact materials, powder metallurgy, material specification, electrical conductivity, contact resistance, mechanical properties, quality assurance, international standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B693 −17 (Reapproved 2022)
Standard Specification for
Silver-Nickel Electrical Contact Materials
This standard is issued under the fixed designation B693; 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 E18 Test Methods for Rockwell Hardness of Metallic Ma-
terials
1.1 This specification covers electrical contact components
E384 Test Method for Microindentation Hardness of Mate-
made from silver nickel by powder metallurgical procedures.
rials
1.2 Thisspecificationcoverscompositionswithinthesilver-
nickel system normally specified by users of electrical con-
3. Ordering Information
tacts.
3.1 Orders for this material under this specification shall
1.3 The values stated in SI units are to be regarded as
include the following information.
standard. No other units of measurement are included in this
3.1.1 Dimensions—Thickness, width, length, diameter, coil
standard.
size or other pertinent sizes (see Section 6).
1.4 This standard does not purport to address all of the
3.1.2 Chemical composition and mechanical properties (see
safety concerns, if any, associated with its use. It is the
reference table in Appendix X1).
responsibility of the user of this standard to become familiar
3.1.3 Physical properties (see Section 5 and reference table
with all hazards including those identified in the appropriate
in Appendix X1).
Safety Data Sheet (SDS) for this product/material as provided
3.1.4 Certification (see Section 12).
by the manufacturer, to establish appropriate safety, health,
and environmental practices, and determine the applicability 3.1.5 Other features as agreed upon between the seller and
the user.
of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard- 4. Alloy Composition and Impurities
ization established in the Decision on Principles for the
4.1 The alloys (material) shall conform to composition and
Development of International Standards, Guides and Recom-
impurity limits as agreed upon between the manufacturer and
mendations issued by the World Trade Organization Technical
user.
Barriers to Trade (TBT) Committee.
4.2 The chemical analysis shall be made in accordance with
2. Referenced Documents the methods described in the newest edition of Annual Book of
ASTM Standards, Vol 03.05 and 03.06, or by any other
2.1 ASTM Standards:
approved method agreed upon between manufacturer and
B328 Test Method for Density, Oil Content, and Intercon-
purchaser.
nected Porosity of Sintered Metal Structural Parts and
Oil-Impregnated Bearings (Withdrawn 2009)
5. Physical and Mechanical Requirements
B476 Specification for General Requirements for Wrought
Precious Metal Electrical Contact Materials
5.1 The manufacturer and purchaser shall agree on qualifi-
cation tests for determination of physical and mechanical
properties.
This specification is under the jurisdiction of ASTM Committee B02 on
5.2 The tests shall be performed on production parts,
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.05 on Precious Metals and Electrical Contact Materials.
wherever practical, or applicable. (Small size contacts do not
Current edition approved April 1, 2022. Published April 2022. Originally
lend themselves to accurate conductivity measurement.)
approved in 1981. Last previous edition approved in 2017 as B693 – 17. DOI:
10.1520/B0693-17R22.
5.3 The tests shall be determined after consideration of the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
function of the part.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
5.4 The typical properties of the most common types of
the ASTM website.
silver-nickel electrical contact materials are given in Table
The last approved version of this historical standard is referenced on
www.astm.org. X1.1 of Appendix X1.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B693 − 17 (2022)
6. Dimensions, Mass, and Permissible Variations bounce, environmental variations, assembly technique and
variations, etc.), this specification cannot ensure performance
6.1 Permissible variations in dimensions shall be within the
control in the application.As part of the qualification on initial
limits specified on drawings describing the contacts and
samples, it is recommended that the user functionally test the
accompanying the order, or shall be within the limits specified
materialselectricallyforalldevicesapplicabletothematerial’s
in the purchase order.
use. This specification provides a means for the contact
manufacturer and contact user to reach agreement on the
7. Workmanship, Finish, and Appearance
details of material to be supplied for a specific use and
7.1 The parts shall be free of defects in material or
reasonable assurance that future lots will be similar in proper-
processing, which would seriously affect their performance.
ties and microstructure to the initial test or sample contact
supplied.
8. Sampling, Testing and Retesting
10. Inspection
8.1 Lot—Unless otherwise spe
...