Neodymium Iron Boron Technical Information

*Magnetic Characteristics 3512 3517 3521
3814
 4017 4514
Residual Induction Br

(G)

 11800 11600 11600 12100 12500 13500

(mT)

1180 1160 1160 1210 1250 1350
 
Coercive Force Hc (Oe) 10300 10800 10900 11300 11700 12300
(kA/m) 820 859 868 899 930 979
 
Intrinsic Coercive Force Hcl (kOe) Minimum 12 17 21 14 17 14
(kA/m) Minimum 955 1353 1672 1114 1353 1115
 
Maximum Energy Product BHmax (MGOe) 35 35 35 38 40 45
(kJ/m3) 279 279 279 303 319 359
Magnetic Characteristics 3512 3517 3521 3814 322 355
Density (lb/in) 0.267 0.267 0.267 0.267 0.273 0.273
(g/cm) 7.4 7.4 7.4 7.4 7.55 7.55
 
Curie Temperature 0F Nominal 600 600 600 600 590 590
0C Nominal 315 315 315 315 312 312
 
**Recommended Maximum Operating Temperature 0F 176 248 302 212 248 230
0C 80 120 150 100 120 110

* Unit magnetic property tolerances are outlined in the MMPA 0100-00, which is available for download on this site. MMPA-0100.
Typical industry tolerances:
Br 1 5% ( Residual Flux Density )
Hc 1 8% ( Coercive Force )
BHmax 1 10% ( Maximum Energy Product )
Hci listed as a minimum ( Intrinsic Coercive Force )

** The maximum operating temperature of a magnet is dependent upon its magnetic characteristics, the magnet or assembly geometry, and how the magnet is utilized. The listed values are guidelines, please consult a DuraMag Engineer for your application.

Manufacturing Processes

Neodymium Iron Boron and Samarium Cobalt are produced by compacting a finely milled metallic powder in the presence of an electromagnetic alignment field. Magnets produced in this manner are anisotropic, and will exhibit a preferred direction of orientation when magnetized. The "green" compacted part is sintered and heat treated in a controlled inert gas atmosphere to achieve full density and optimize the magnetic properties. Final shaping of the magnet is accomplished by grinding with diamon abrasives. Normally these magents are ground only on the pole faces, all other surfaces would exhibit as pressed dimensions and surface conditions.

Temperature Characteristics

If the Neodymium and Samarium Cobalt materials are required to operate at temperatures other than ambient, consideration must be given to the effect on the magnet's performance. Normally operating below 200C causes no adverse effects, and in fact performance increases with decreasing temperatures. The Neodymium materials do exhibit a temporary, or reversible loss of flux with increasing temperatures. The severity of these losses and the possiblity of permanent, or irreversible losses must be considered when the design is being developed. The grade of material, temperature extremes, magnet geometry, and circuit configuration will all influence the ability of a given device to withstand   adverse thermal conditions without experiencing unexpected losses. Please consult the individual product data sheets for specific temperature data, or consult our application engineering department for additional information.

Physical Characteristics

Neodymium magnets are stronger mechanically than most other permanent magnet materials. Even with this improved mechanical strength they should not be considered as structural components, and should be handled with some care to minimize any possible chipping or breakage. Minor imperfections such as chips, surface porosity, or other similar characteristics can occur with any permanent magnet material. These imperfections will not effect the magnet's performance, and should not be considered cause for rejection. Duramag will work with you to develop a mutually agreed upon visual inspection standard to insure that only acceptable physical characteristics are present in any parts we supply. The high iron content of Neodymium makes it prone to oxidation. Depending upon the environment in which the magnet is destined to operate, a variety of coatings or surface treatments may provide adequate protection from corrosion.

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