1、Designation: A1054 16Standard Specification forSintered Ferrite Permanent Magnets1This standard is issued under the fixed designation A1054; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers technically important, com-mercially available, magnetically hard sintered ferrite perma-nent magnets.1.2 Ferrite permanen
3、t magnets have residual induction Brfrom 0.2 T (2000 G) up to about 0.5 T (5000 G) and intrinsiccoercive field strength HcJfrom 160 kA m (2000 Oe) up toabout 400 kA/m (5000 Oe). Their specific magnetic hysteresisbehavior (demagnetization curve) can be characterized usingTest Method A977/A977M.1.3 Th
4、e values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to customary (cgs-emu and inch-pound) unitswhich are provided for information only and are not consideredstandard.1.4 This standard does not purport to address all of thesafety conc
5、erns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A340 Terminology of Symbols and Definit
6、ions Relating toMagnetic TestingA977/A977M Test Method for Magnetic Properties of High-Coercivity Permanent Magnet Materials Using Hyster-esigraphs2.2 Other Standards:MMPA Standard No. 0100-00 Standard Specifications forPermanent Magnet Materials3IEC 60404-8-1 Magnetic Materials Part 8: Specificatio
7、ns forindividual materials Section 1 Standard specificationsfor magnetically hard materials43. Terminology3.1 The terms and symbols used in this specification aredefined in Terminology A340.3.2 Terms that are not defined in Terminology A340 but arein common usage and used herein are as follows.3.2.1
8、 Recoil permeability, REC, is the permeability corre-sponding to the slope of the recoil line. For reference, seeincremental, relative, and reversible permeabilities as definedin Terminology A340. In practical use, this is the slope of thenormal hysteresis loop in the second quadrant and in proximit
9、yto the B-axis. The value of recoil permeability is dimension-less. Note that in producers product literature, recoil perme-ability is sometimes represented by the symbol r, which isdefined by Terminology A340 as relative permeability.3.2.2 Magnetic characteristics change with temperature.Two key me
10、trics of permanent magnet performance are re-sidual induction, Br, and intrinsic coercive field strength, HcJ.The change in these characteristics over a defined and limitedtemperature range can be reversible, that is, non-destructive.This change is represented by values called reversible tempera-tur
11、e coefficients. The symbol for reversible temperature coef-ficient of induction is (Br) and of (intrinsic) coercivity is(HcJ). They are expressed in percent change per degreeCelsius, %/C, or the numerically equivalent percent perKelvin, %/K. The change in magnetic characteristics is non-linear so it
12、 is necessary to specify the temperature range overwhich the coefficient applies.3.2.3 The maximum recommended working temperature ofa permanent magnet, Tw, is a semi-arbitrary value sometimesassigned by magnet manufacturers to their products. Twis notnormative. See Appendix X3 for a more complete d
13、iscussion.4. Classification4.1 The classification of ferrite permanent magnets is givenin Tables 1 and 2, with cross-reference to MMPA Standard No.0100-00 and IEC 60404-8-1 standards.1This specification is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsib
14、ility of Subcommittee A06.02 onMaterial Specifications.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 2007. Last previous addition approved in 2014 as A1054 14. DOI:10.1520/A1054-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
15、 ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from The International Magnetics Association (IMA), 8 SouthMichigan Avenue, Suite 1000, Chicago, IL 60603.4Available from IEC (In
16、ternational Electrotechnical Commission) Central Office3, rue de Varemb, 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 States15. Ordering Information5.1 Orders for parts conforming to this spe
17、cification shallinclude the following information:5.1.1 Reference to this standard and year of issue/revision.5.1.2 Reference to an applicable part drawing.5.1.3 Magnetic property requirements if they are morestringent than the minimum values listed in the tables.5.1.4 Quantity required.5.1.5 The re
18、quired magnetization state of the providedmaterial (unmagnetized, fully magnetized, magnetized andthermally stabilized, magnetized and partially demagnetized or“calibrated”). This information should appear on the partdrawing whenever possible.5.1.6 Certification of magnetic property evaluation.5.1.7
19、 Marking and packaging requirements.5.1.8 Exceptions to this specification or special require-ments such as plating, coating, or functional testing as mutuallyagreed upon by the producer and user.6. Chemical Composition6.1 The general chemical composition of ferrite magnets isMO 6Fe2O3with M being b
20、arium, strontium (strontiumpreferred due to environmental issues), or some combination ofthe two. New ferrite grades may also include some rare earthelements and cobalt. Chemical compositions listed in the tablesare typical and are not guaranteed.7. Physical and Mechanical Properties7.1 Typical ther
21、mal properties are listed in Appendix X1.7.2 Typical physical properties are listed in Appendix X2.TABLE 1 Classification and Minimum Magnetic Property Requirements for Isotropic Sintered Ferrite Permanent MagnetsMaterial Magnetic PropertiesASTMDesignationAMMPABriefDesignationOriginalMMPAClassIECBri
22、efDesigna-tionIECCodeRefer-enceMaximumEnergyProduct,(BH)maxkJ/m3(MGOe)RemanentInductionBr,mT (gauss)NormalCoerciveField Strength,HcBkA/m (oersted)IntrinsicCoerciveField Strength,HcJkA/m (oersted)RelativeRecoilPermeability,RECCE-I-01 1.03/3 Ceramic1. S1-0-1 8.4 (1.05) 230 (2300) 148 (1860) 259 (3250)
23、 1.2ADesignations are XX-Y-ZZZ where:XX = material type (CE = ceramic ferrite),Y = processing and orientation (I = isotropic (non-oriented), A = anisotropic (oriented), andZZZ = numeric grade designation.TABLE 2 Classification and Minimum Magnetic Property Requirements for Anisotropic Sintered Ferri
24、te Permanent MagnetsMaterial Magnetic PropertiesASTMDesignationAMMPABriefDesignationOriginalMMPAClassIECBriefDesigna-tionIECCodeRefer-enceMaximumEnergyProduct,(BH)maxkJ/m3(MGOe)RemanentInductionBr,mT (gauss)NormalCoerciveField Strength,HcBkA/m (oersted)IntrinsicCoerciveField Strength,HcJkA/m (oerste
25、d)RelativeRecoilPermeabilityRECCE-A-02 . Ceramic2. . 14.3 (1.8) 290 (2900) 191 (2400) 239 (3000) 1.1CE-A-05 3.4/2.5 Ceramic5Hard fer-rite 26/18S1-1-6 27.1 (3.40) 380 (3800) 191 (2400) 199 (2500) 1.1CE-A-06 . Ceramic6. . 19.5 (2.45) 320 (3200) 225 (2820) 263 (3300) 1.1CE-A-07 2.7/4.0 Ceramic7Hard fer
26、-rite 20/28S1-1-2 21.9 (2.75) 340 (3400) 259 (3250) 318 (4000) 1.1CE-A-08A3.5/3.1 Ceramic8AHard fer-rite 25/12S1-1-5 27.9 (3.50) 385 (3850) 235 (2950) 243 (3050) 1.1CE-A-08B. Ceramic8B. . 32.8 (4.12) 420 (4200) 232 (2913) 236 (2960) 1.1CE-A-10 . Ceramic10. . 30.4 (3.82) 400 (4000) 280 (3510) 288 (36
27、17) 1.1CE-A-11 . Ceramic11. . 34.4 (4.32) 430 (4300) 200 (2512) 204 (2560) 1.1CE-A-21 3.4/3.9 . . . 27.1 (3.40) 380 (3800) 271 (3400) 310 (3900) 1.1CE-A-22 4.0/2.9 . . . 31.8 (4.00) 410 (4100) 223 (2800) 231 (2900) 1.1CE-A-23 3.2/4.8 . . . 25.5 (3.20) 370 (3700) 279 (3500) 382 (4800) 1.1CE-A-24 3.8/
28、4.0 . . . 30.3 (3.80) 400 (4000) 290 (3560) 318 (4000) 1.1ADesignations are XX-Y-ZZZ where:XX = material type (CE = ceramic ferrite),Y = processing and orientation (I = isotropic (non-oriented), A = anisotropic (oriented), andZZZ = numeric grade designation.A1054 1627.3 Physical density values in Ap
29、pendix X2 are given forinformation purposes only and are not guaranteed.7.4 Strength testing of brittle materials such as ferritepermanent magnets is difficult, expensive, and time-consuming. Results can be widely distributed. Producers typi-cally make these measurements at the onset of production a
30、ndthey are seldom repeated.8. Magnetic Property Requirements8.1 Magnetic properties are listed in Tables 1 and 2.8.2 The values of essential magnetic properties listed in thetable are specified minimum values at +20 6 2 C (+68 64 F), determined after magnetizing to saturation.8.3 The specified value
31、s of magnetic properties are validonly for magnet test specimens with a uniform cross-sectionalong the axis of magnetization. Properties for anisotropic(magnetically oriented) magnets are measured along the axis ofpreferred orientation.8.4 Because of the nature of permanent magnet production,magneti
32、c testing of each lot is strongly recommended, espe-cially for applications where the magnet performance is closelyspecified. Such magnetic property evaluations shall be con-ducted in the manner described below. Where the magnet shapeis not suitable for magnetic testing, a specimen shall be cutfrom
33、the magnet using appropriate slicing and grindingtechniques, paying attention to any magnetic orientation withinthe magnet.8.4.1 The magnetic properties shall be determined in accor-dance with Test Method A977/A977M, or by using a suitable,mutually agreed upon magnetometric method.8.4.2 When magnets
34、 are being purchased in the fullymagnetized condition, the testing shall determine the magneticproperties from the as-received magnetization state, followedby magnetization to saturation and testing of the magneticproperties from the fully magnetized condition.8.4.3 When magnets are being purchased
35、in the unmagne-tized condition or in an unknown state of magnetization, thetest laboratory shall magnetize the test specimen(s) to satura-tion and measure the magnetic properties from the fullymagnetized condition.8.4.4 When magnets are being purchased in a calibrated,stabilized, or “knocked-down” c
36、ondition, magnets should behandled with care to prevent exposure to externally appliedfields. Refer to Appendix X3 for an explanation of these terms.8.4.5 Other test methods may be utilized as agreed tobetween producer and user. Such tests may include the opencircuit magnetic field strength Helmholt
37、z test, field strengthmeasurements in a defined magnetic circuit, or magnetic fluxdensity measurements adjacent to the magnet surface.9. Workmanship, Finish, and Appearance9.1 Dimensions and tolerances shall be as specified on themagnet drawing and must be agreed upon between the pro-ducer and user.
38、9.2 Porosity and voids are common in sintered ferritemagnets and shall not in themselves constitute reason forrejection unless agreed upon between producer and user.Allowable defects shall be documented in writing as part of theordering or contracting process.9.3 Magnets shall be free of loose chips
39、 and surface residuewhich may interfere with assembly or proper device function.9.4 Chips shall be acceptable if no more than 5 % of anysurface identified as a magnetic pole surface is removed.9.5 Cracks visible to the naked eye shall not be permittedunless otherwise agreed to by producer and user.1
40、0. Sampling10.1 A lot shall consist of parts of the same form anddimensions, produced from a single mixed powder batch orsintering run, or both, from an unchanged process, withoutdiscontinuity in production, and submitted for inspection at onetime.10.2 The producer and user shall agree upon a repres
41、enta-tive number of specimens for testing. Typically, a suitablenumber of parts, as mutually agreed upon between producerand user, shall be randomly selected from each lot. It isadvisable to test a minimum of two parts from each lot, andmore if there is reason to suspect that the magnetic properties
42、are not uniform throughout the lot.11. Rejection and Rehearing11.1 Parts that fail to conform to the requirements of thisspecification shall be rejected. Rejection should be reported tothe producer or supplier promptly and in writing. In case ofdissatisfaction with the results of the test, the produ
43、cer maymake claim for a rehearing.11.2 The disposition of rejected parts shall be subject toagreement between the user and the producer.12. Certification12.1 When specified in the purchase order or contract, theuser shall be furnished certification that samples representingeach lot have been either
44、tested or inspected as directed in thisspecification and that the requirements have been met.12.2 When specified in the purchase order or contract, areport of the test results shall include:12.2.1 Grade of material.12.2.2 Magnetic test results.12.2.3 The results of any other tests stipulated in thep
45、urchase order or contract.13. Packaging and Package Marking13.1 Packaging shall be subject to agreement between theuser and the producer.13.2 Parts furnished under this specification shall be in acontainer identified by the name or symbol of the partsproducer.13.3 Magnetized parts shall be properly
46、labeled as such forsafe handling and shipping purposes.13.3.1 Magnetized parts to be shipped via aircraft must bepackaged in an appropriate manner to meet requirements for airshipment. These requirements may vary depending upon local,A1054 163national, and international laws. It is the responsibilit
47、y of theproducer to ensure packaging meets all relevant regulations.This may require rearranging the parts within the shippingcontainer, adding sheets of steel or other magnetically softshielding material, or both, or other specialized packagingprocedures as determined by regulation, carrier policy,
48、 or byagreement between producer and user, to reduce the magneticfield external to the shipping container below the requiredlevels.14. Keywords14.1 ceramic magnet; coercive field strength; ferrite; ferritemagnet; hard ferrite; magnetic induction; magnetic properties;permanent magnet; sintered cerami
49、c ferrite; sintered ferritemagnetAPPENDIXES(Nonmandatory Information)X1. TYPICAL THERMAL PROPERTIES OF FERRITE PERMANENT MAGNETSReversible temperature coefficient of residual induction -0.2 % CReversible temperature coefficient of intrinsic coercive field strength +0.2 to +0.5 % CCurie temperature 450 CMaximum exposure temperature without structural change 800 CX2. TYPICAL PHYSICAL PROPERTIES OF FERRITE PERMANENT MAGNETSDensity 4.9 to 5.1 g/cm3(0.177 to 0.184 lb/in.3)Coefficient of thermal expansionPerpendicular to magnetic orientation 10 ppm/CParallel to
