ASTM A1054-16

Standard Specification for Sintered Ferrite Permanent Magnets

ABSTRACT
This specification covers technically important, commercially available, magnetically hard sintered ceramic ferrite permanent magnets. Magnetic properties such as remanence, coercive field strength, and relative recoil permeability shall be measured. The specified magnetic properties are valid only for magnet test specimens with a uniform cross-section along the axis of magnetization. Properties for anisotropic magnets shall be measured along the axis of preferred orientation.
SCOPE
1.1 This specification covers technically important, commercially available, magnetically hard sintered ferrite permanent magnets.  
1.2 Ferrite permanent magnets have residual induction Br from 0.2 T (2000 G) up to about 0.5 T (5000 G) and intrinsic coercive field strength HcJ from 160 kA/m (2000 Oe) up to about 400 kA/m (5000 Oe). Their 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 health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Oct-2016
• ICS: 29.030 - Magnetic materials
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.02 - Material Specifications

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:A1054 −16
Standard Specification for
1
Sintered Ferrite Permanent Magnets
This standard is issued under the fixed designation A1054; 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 IEC 60404-8-1 Magnetic Materials Part 8: Specifications for
individual materials Section 1 – Standard specifications
1.1 This specification covers technically important, com-
4
for magnetically hard materials
mercially available, magnetically hard sintered ferrite perma-
nent magnets.
3. Terminology
1.2 Ferrite permanent magnets have residual induction B
r
3.1 The terms and symbols used in this specification are
from 0.2 T (2000 G) up to about 0.5 T (5000 G) and intrinsic
defined in Terminology A340.
coercive field strength H from 160 kA⁄m (2000 Oe) up to
cJ
3.2 Terms that are not defined in Terminology A340 but are
about 400 kA/m (5000 Oe). Their specific magnetic hysteresis
in common usage and used herein are as follows.
behavior (demagnetization curve) can be characterized using
3.2.1 Recoil permeability, µ , is the permeability corre-
Test Method A977/A977M.
REC
sponding to the slope of the recoil line. For reference, see
1.3 The values stated in SI units are to be regarded as
incremental, relative, and reversible permeabilities as defined
standard. The values given in parentheses are mathematical
in Terminology A340. In practical use, this is the slope of the
conversions to customary (cgs-emu and inch-pound) units
normal hysteresis loop in the second quadrant and in proximity
whichareprovidedforinformationonlyandarenotconsidered
to the B-axis. The value of recoil permeability is dimension-
standard.
less. Note that in producers’ product literature, recoil perme-
1.4 This standard does not purport to address all of the
ability is sometimes represented by the symbol µ , which is
r
safety concerns, if any, associated with its use. It is the
defined by Terminology A340 as relative permeability.
responsibility of the user of this standard to establish appro-
3.2.2 Magnetic characteristics change with temperature.
priate safety and health practices and determine the applica-
Two key metrics of permanent magnet performance are re-
bility of regulatory limitations prior to use.
sidual induction, B , and intrinsic coercive field strength, H .
r cJ
The change in these characteristics over a defined and limited
2. Referenced Documents
temperature range can be reversible, that is, non-destructive.
2
2.1 ASTM Standards: Thischangeisrepresentedbyvaluescalledreversibletempera-
A340 Terminology of Symbols and Definitions Relating to ture coefficients. The symbol for reversible temperature coef-
Magnetic Testing ficient of induction is α(B ) and of (intrinsic) coercivity is
r
A977/A977M Test Method for Magnetic Properties of High- α(H ). They are expressed in percent change per degree
cJ
Coercivity Permanent Magnet Materials Using Hyster- Celsius, %/°C, or the numerically equivalent percent per
esigraphs Kelvin, %/K. The change in magnetic characteristics is non-
linear so it is necessary to specify the temperature range over
2.2 Other Standards:
which the coefficient applies.
MMPA Standard No. 0100-00 Standard Specifications for
3
3.2.3 The maximum recommended working temperature of
Permanent Magnet Materials
a permanent magnet, T , is a semi-arbitrary value sometimes
w
assigned by magnet manufacturers to their products. T is not
w
1 normative. See Appendix X3 for a more complete discussion.
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.
4. Classification
Current edition approved Nov. 1, 2016. Published November 2016. Originally
4.1 The classification of ferrite permanent magnets is given
approved in 2007. Last previous addition approved in 2014 as A1054 – 14. DOI:
10.1520/A1054-16.
in Tables 1 and 2, with cross-reference to MMPAStandard No.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
0100-00 and IEC 60404-8-1 standards.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
Available from The International Magnetics Association (IMA), 8 South Available from IEC (International Electrotechnical Commission) Central Office
Michigan Avenue, Suite 1000, Chicago, IL 60603. 3, rue de Varembé, P.O. Box 131, CH - 1211, GENEVA 20 Switzerland.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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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: A1054 − 14 A1054 − 16
Standard Specification for
1
Sintered Ceramic Ferrite Permanent Magnets
This standard is issued under the fixed designation A1054; 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 ceramic ferrite
permanent magnets.
1.2 Ceramic ferriteFerrite permanent magnets have residual magnetic induction BrB from 2000 G (0.2 T)0.2 T (2000 G) up to
r
about 5000 G (0.5 T)0.5 T (5000 G) and intrinsic coercive field strength H (H ) from 2000160 kA Oe (160 kA⁄m (2000 Oe)⁄m)
ci cJ
up to about 5000 Oe (400 kA/m).400 kA/m (5000 Oe). Their specific magnetic hysteresis behavior (demagnetization curve) can
be characterized using Test Method A977/A977M.
1.3 The values stated in customary (cgs-emu and inch-pound) SI units are to be regarded as standard. The values given in
parentheses are mathematical conversions to SI 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 health practices and determine the applicability of regulatory
limitations prior to use.
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
2.2 Other Standards:
3
MMPA Standard No. 0100-00 Standard Specifications for Permanent Magnet Materials
IEC 60404-8-1 60404-8-1, Magnetic Materials Part 8: Specifications for individual materials Section 1 – Standard specifications
4
for magnetically hard materials
5
International Air Transport Association (IATA) Dangerous Goods Regulations, Packing Instruction 902
3. Terminology
3.1 The terms and symbols used in this specification 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 permeability is dimensionless. Note that in
producers’ product literature, recoil permeability is sometimes represented by the symbol μ , which is defined by Terminology
r
A340 as relative permeability.
3.2.2 Magnetic characteristics change with temperature. Two key metrics of permanent magnet performance are residual
induction, B , and intrinsic coercive field strength, H . The change in these characteristics over a defined and limited temperature
r cJ
range can be reversible, that is, non-destructive. This change is represented by values called reversible temperature coefficients.
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 May 15, 2014Nov. 1, 2016. Published June 2014November 2016. Originally approved in 2007. Last previous addition approved in 20072014
as A1054A1054 – 14.-07. DOI: 10.1520/A1054-07.10.1520/A1054-16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from The International Magnetics Association (IMA), 8 South Michigan Avenue, Suite 1000, Chicago, IL 60603.
4
Available from IEC (International Electrotechnical Commission) Central Office 3, rue de Varembé, P.O. Box 131, CH - 1211, GENEVA 20 Switzerland.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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A1054 − 16
The symbol for reversible temperature coefficient of induction is α(B ) and of (intrinsic) coercivity is α(H ). They are exp
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