ASTM A1101-23
(Specification)Standard Specification for Sintered and Fully Dense Neodymium Iron Boron (NdFeB) Permanent Magnets
Standard Specification for Sintered and Fully Dense Neodymium Iron Boron (NdFeB) Permanent Magnets
ABSTRACT
This specification covers technically important, commercially available, magnetically hard sintered and fully dense neodymium iron boron (Nd2Fe14B, NdFeB, or “Neo”) permanent magnets. These materials are available in a wide range of compositions with a commensurately large range of magnetic properties. Neodymium iron boron magnets have approximate magnetic properties of residual magnetic induction from 1.08 T (10 800 G) up to 1.5 T (15 000 G) and intrinsic coercive field strength of 875 kA/m (11 000 Oe) to above 2785 kA/m (35 000 Oe). Special grades and isotropic (un-aligned) magnets can have properties outside these ranges.
SCOPE
1.1 This specification covers technically important, commercially available, magnetically hard sintered and fully dense neodymium iron boron (Nd2Fe14B, NdFeB, or “Neo”) permanent magnets. These materials are available in a wide range of compositions with a commensurately large range of magnetic properties. The numbers in the Nd2Fe14B name indicate the approximate atomic ratio of the key elements.
1.2 Anisotropic (aligned) sintered and fully dense neodymium iron boron magnets have approximate magnetic properties of residual magnetic induction, Br, from 1.08 T
(10 800 G) up to 1.5 T (15 000 G) and intrinsic coercive field strength, HcJ, of 875 kA/m (11 000 Oe) to above 2785 kA/m (35 000 Oe). Fully dense but not sintered magnets include hot-deformed magnets using a plastic deformation technique, such as upsetting or extrusion, at elevated temperatures for the crystallographic alignment, as opposed to magnetic field alignment in sintered magnets. Special grades and isotropic (un-aligned) magnets can have properties outside these ranges (see Appendix X4). Specific magnetic hysteresis behavior (demagnetization curve) can be characterized using Test Method A977/A977M.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to customary (cgs-emu and inch-pound) units which are provided for information only and are not considered 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 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.
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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: A1101 − 23
Standard Specification for
Sintered and Fully Dense Neodymium Iron Boron (NdFeB)
1
Permanent Magnets
This standard is issued under the fixed designation A1101; 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 Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This specification covers technically important, com-
Barriers to Trade (TBT) Committee.
mercially available, magnetically hard sintered and fully dense
neodymium iron boron (Nd Fe B, NdFeB, or “Neo”) perma-
2 14
2. Referenced Documents
nent magnets. These materials are available in a wide range of
2
2.1 ASTM Standards:
compositions with a commensurately large range of magnetic
A340 Terminology of Symbols and Definitions Relating to
properties. The numbers in the Nd Fe B name indicate the
2 14
Magnetic Testing
approximate atomic ratio of the key elements.
A977/A977M Test Method for Magnetic Properties of High-
1.2 Anisotropic (aligned) sintered and fully dense neo-
Coercivity Permanent Magnet Materials Using Hyster-
dymium iron boron magnets have approximate magnetic prop-
esigraphs
erties of residual magnetic induction, B , from 1.08 T
r
2.2 Other Standards:
(10 800 G) up to 1.5 T (15 000 G) and intrinsic coercive field
MMPA Standard No. 0100-00 Standard Specifications for
strength, H , of 875 kA ⁄m (11 000 Oe) to above 2785 kA ⁄m
cJ
3
Permanent Magnet Materials
(35 000 Oe). Fully dense but not sintered magnets include
IEC 60404-8-1 Magnetic Materials Part 8: Specifications for
hot-deformed magnets using a plastic deformation technique,
Individual Materials Section 1 – Standard Specifications
such as upsetting or extrusion, at elevated temperatures for the
4
for Magnetically Hard Materials
crystallographic alignment, as opposed to magnetic field align-
ment in sintered magnets. Special grades and isotropic (un-
3. Terminology
aligned) magnets can have properties outside these ranges (see
3.1 The terms and symbols used in this specification, unless
Appendix X4). Specific magnetic hysteresis behavior (demag-
netization curve) can be characterized using Test Method otherwise noted, are defined in Terminology A340.
A977/A977M.
3.2 Terms that are not defined in Terminology A340 but are
1.3 The values stated in SI units are to be regarded as in common usage and used herein are as follows.
3.2.1 Recoil permeability, μ , is the permeability corre-
standard. The values given in parentheses are mathematical
(rec)
conversions to customary (cgs-emu and inch-pound) units sponding to the slope of the recoil line. For reference see
incremental, relative, and reversible permeabilities as defined
which are provided for information only and are not considered
standard. in Terminology A340. In practical use, this is the slope of the
normal hysteresis loop in the second quadrant and in proximity
1.4 This standard does not purport to address all of the
to the B-axis. The value of recoil permeability is dimension-
safety concerns, if any, associated with its use. It is the
less. Note that in producers’ product literature recoil perme-
responsibility of the user of this standard to establish appro-
ability is sometimes represented by the symbol μ , which is
r
priate safety, health, and environmental practices and deter-
defined by Terminology A340 as relative permeability.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ization established in the Decision on Principles for the
contact ASTM 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.
1 3
This specification is under the jurisdiction of ASTM Committee A06 on This standard is no longer actively maintained but it is still available from the
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on Permanent Magnet Division of A3 (Association for Advancing Automation),
Material Specifications. http://www.automate.org.
4
Current edition approved Dec. 1, 2023. Published January 2024. Originally Available from International Electrotechnical Commission (IEC), 3, rue de
approved in 2016. Last previous edition was approved in 2016 as A1101 – 16. DOI:
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM 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.
Designation: A1101 − 16 A1101 − 23
Standard Specification for
Sintered and Fully Dense Neodymium Iron Boron (NdFeB)
1
Permanent Magnets
This standard is issued under the fixed designation A1101; 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
1.1 This specification covers technically important, commercially available, magnetically hard sintered and fully dense
neodymium iron boron (Nd Fe B, NdFeB, or “Neo”) permanent magnets. These materials are available in a wide range of
2 14
compositions with a commensurately large range of magnetic properties. The numbers in the Nd Fe B name indicate the
2 14
approximate atomic ratio of the key elements.
1.2 Neodymium Anisotropic (aligned) sintered and fully dense neodymium iron boron magnets have approximate magnetic
properties of residual magnetic induction, B , from 1.08 T1.08 T
r
(10 800 G) 800 G) up to 1.5 T (15 000 G) 1.5 T (15 000 G) and intrinsic coercive field strength, H , of 875875 kA kA/m (11 000
cJ
Oe) to above 2785⁄m (11 000 Oe) to above 2785 kA kA/m (35 000 Oe). ⁄m (35 000 Oe). Fully dense but not sintered magnets
include hot-deformed magnets using a plastic deformation technique, such as upsetting or extrusion, at elevated temperatures for
the crystallographic alignment, as opposed to magnetic field alignment in sintered magnets. Special grades and isotropic
(un-aligned) magnets can have properties outside these ranges (see Appendix X4). Specific magnetic hysteresis behavior
(demagnetization curve) can be characterized using Test Method A977/A977M.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to
customary (cgs-emu and inch-pound) units which are provided for information only and are not considered 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 establish appropriate safety and healthsafety, 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.
2. Referenced Documents
2
2.1 ASTM Standards:
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A977/A977M Test Method for Magnetic Properties of High-Coercivity Permanent Magnet Materials Using Hysteresigraphs
1
This specification is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on Material
Specifications.
Current edition approved Nov. 1, 2016Dec. 1, 2023. Published November 2016January 2024. Originally approved in 2016. Last previous edition was approved in 2016
as A1101 – 16. DOI: 10.1520/A1101–1610.1520/A1101-23
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM 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
1
---------------------- Page: 1 ----------------------
A1101 − 23
2.2 Other Standards:
3
MMPA Standard No. 0100-00 Standard Specifications for Permanent Magnet Materials
IEC 60404-8-1 Magnetic Materials Part 8: Specifications for Individual Materials Section 1 – Standard Specifications for
4
Magnetically Hard Materials
3. Terminology
3.1 The terms and symbols used in this specification, unless otherwise noted, are defined in Terminology A340.
3.2 Terms that are not defined in Terminology A340 but are in common usage and used herein are as follows.
3.2.1 Recoil permeability, μ , is the permeability corresponding to the slope of the recoil line. For reference see incremental,
(rec)
relative, and reversible permeabilities as defined in Terminology A340. In practical use, this is the slope of the normal hysteresis
loop in the second quadrant and in proximity to the B-axis. The value of recoil perm
...
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