(Magnetic and Physical Characteristics)

Many grades of Neodymium magnets exist to support a variety of industrial applications.  The range of Neo grades typically extends from 33 MGOe to 52 MGOe.  This range allows for optimizing cost, performance, and operational temperature resistance.

The typical convention for “Grade” is to use the value of the particular magnet alloy’s Energy Density or Maximum Energy Product.  Oftentimes there are letters or a two digit number suffix attached to the Grade which indicates the Intrinsic Coercive Force (Hci) level of the magnet alloy.  This Hci is a good indicator of the maximum allowable temperature a particular Neo alloy can tolerate before irreversible demagnetizing occurs.

The higher the “Grade number” then the higher the Energy Density.  Usually the higher the Energy Density the stronger the magnet, but this is very much dependent upon the magnet’s operational environment.

* Maximum Operating Temperature for this Group is 60°C / 140°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
5011	ND-50	14.0 - 14.5	1.40 - 1.45	10.5	836	11	876	47 - 51	374 - 406
5211	ND-52	14.4 -14.8	1.44 - 1.48	10.5	836	11	876	49 - 53	390 - 422

* Maximum Operating Temperature for this Group is 80°C / 176°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
3512	ND-35	11.8 - 12.3	1.18 - 1.23	10.9	868	12	955	34 - 36	263 - 287
3812	ND-38	12.3 - 12.6	1.23 - 1.26	11.3	899	12	955	36 - 39	287 - 311
4012	ND-40	12.6 - 12.9	1.26 - 1.29	11.4	907	12	955	38 - 41	302 - 327
4212	ND-42	12.9 - 13.3	1.29 - 1.33	11.5	915	12	955	40 - 43	318 - 342
4512	ND-45	13.3 - 13.7	1.33 - 1.37	11.0	876	12	955	43 - 46	342 - 366
4812	ND-48	13.7-14.1	1.37 - 1.41	10.5	836	12	955	45 - 49	358 - 390

* Maximum Operating Temperature for this Group is 100°C / 212°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
3314	ND-33M	11.3 - 11.8	1.13 - 1.18	10.5	836	14	1,114	31 - 34	247 - 271
3514	ND-35M	11.8 - 12.3	1.18 - 1.23	10.9	868	14	1,114	34 - 36	263 - 287
3814	ND-38M	12.3 - 12.6	1.23 - 1.26	11.3	899	14	1,114	36 - 39	287 - 311
4014	ND-40M	12.6 - 12.9	1.26 - 1.29	11.6	923	14	1,114	38 - 41	302 - 327
4214	ND-42M	12.9 - 13.3	1.29 - 1.33	12.0	955	14	1,114	40 - 43	318 - 342
4514	ND-45M	13.3 - 13.7	1.33 - 1.37	12.5	995	14	1,114	43 - 46	342 - 366
4814	ND-48M	13.7 -14.1	1.37 - 1.41	12.9	1,027	14	1,114	45 - 49	358 - 390
5014	ND-50M	14.0 - 14.5	1.40 - 1.45	13.0	1,033	14	1,114	47 - 51	374 - 406

* Maximum Operating Temperature for this Group is 120°C / 248°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
3017	ND-30H	10.8 - 11.3	1.08 - 1.13	10	796	17	1,353	28 - 31	223 - 247
3317	ND-33H	11.3 - 11.8	1.13 - 1.18	10.5	836	17	1,353	31 - 34	247 - 271
3517	ND-35H	11.8 - 12.3	1.18 - 1.23	10.9	868	17	1,353	34 - 36	263 - 287
3817	ND-38H	12.3 - 12.6	1.23 - 1.26	11.3	899	17	1,353	36 - 39	287 - 311
4017	ND-40H	12.6 - 12.9	1.26 - 1.29	11.6	923	17	1,353	38 - 41	302 - 327
4217	ND-42H	12.9 - 13.3	1.29 - 1.33	12	955	17	1,353	40 - 43	318 - 342
4517	ND-45H	13.3 - 13.7	1.3 - 1.37	12.3	979	17	1,353	43 - 46	342-366
4817	ND-48H	13.7 - 14.1	1.37 - 1.41	12.5	995	17	1,353	45 - 49	358-390

* Maximum Operating Temperature for this Group is 150°C / 302°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
3020	ND-30SH	10.8 - 11.4	1.08 - 1.14	10.1	804	20	1,592	28 - 31	223 - 247
3320	ND-33SH	11.4 - 11.8	1.14 - 1.18	10.6	844	20	1,592	31 - 34	247 - 271
3520	ND-35SH	11.8 - 12.3	1.18 - 1.23	11.0	876	20	1,592	33 - 36	263 - 287
3820	ND-38SH	12.3 - 12.6	1.23 - 1.26	11.4	907	20	1,592	36 - 39	287 - 311
4020	ND-40SH	12.6 - 12.9	1.26 - 1.29	11.6	939	20	1,592	38 - 41	302 - 326
4220	ND-42SH	12.9 - 13.3	1.29 - 1.33	12.4	987	20	1,592	40 - 43	318 - 342
4520	ND-45SH	13.3 - 13.7	1.33 - 1.37	12.6	1,003	20	1,592	42 - 46	334 - 366

* Maximum Operating Temperature for this Group is 180°C / 356°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
2825	ND-28UH	10.4 - 10.8	1.04 - 1.08	9.6	764	25	1,989	26 - 29	207 - 231
3025	ND-30UH	10.8 - 11.4	1.08 - 1.14	10.1	804	25	1,989	28 - 31	223 - 247
3325	ND-33UH	11.4 - 11.8	1.14 - 1.18	10.7	852	25	1,989	31 - 34	247 - 271
3525	ND-35UH	11.8 - 12.3	1.18 - 1.23	10.8	860	25	1,989	33 - 36	263 - 287
3825	ND-38UH	12.3 - 12.6	1.23 - 1.26	11.3	899	25	1,989	36 - 39	287 - 311
4025	ND-40UH	12.5 - 12.9	1.25 - 1.29	11.4	907	25	1,989	38 - 41	302 - 326
4225	ND-42UH	12.8 - 13.3	1.28 - 1.33	11.6	923	25	1,989	40 - 43	318 - 342

* Maximum Operating Temperature for this Group is 200°C / 392°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
2830	ND-28EH	10.4 - 10.8	1.04 - 1.08	9.8	780	30	2,388	26 - 29	207 - 231
3030	ND-30EH	10.8 - 11.4	1.08 - 1.14	10.1	804	30	2,388	28 - 31	223 - 247
3330	ND-33EH	11.4 - 11.8	1.14 - 1.18	10.3	820	30	2,388	31 - 34	247 - 271
3530	ND-35EH	11.7 - 12.3	1.17 - 1.23	10.5	836	30	2,388	33 - 36	263 - 287
3830	ND-38EH	12.2- 12.6	1.22 - 1.26	11.3	899	30	2,388	35 - 39	278 - 311

* Maximum Operating Temperature for this Group is 230°C / 446°F ( L/D ≥0.7)
Dura Magnet Grade	Common Industry Notation	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max
		Range		Minimum		Minimum		Range
		k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3
2835	ND-28AH	10.4 - 10.9	1.04 - 1.09	9.8	780	35	2,785	26 - 29	207 - 231
3035	ND-30AH	10.8 - 11.3	1.08 - 1.13	10.1	804	35	2,785	28 - 31	223 - 247
3335	ND-33AH	11.3 - 11.8	1.13 - 1.18	10.3	820	33	2,625	31 - 34	247 - 271
3535	ND-35AH	11.7 - 12.3	1.17 - 1.23	10.5	836	33	2,625	33 - 36	263 - 287

Reversible Temperature Coefficients (0°C to 100°C)
Intrinsic Coercive Force (Hci)	Induction Br (G)	Intrinsic Coercivity Hci (Oe)
(KOe)	(%)	(%)
11	-0.12%	-0.70%
12	-0.12%	-0.70%
14	-0.12%	-0.65%
17	-0.11%	-0.65%
20	-0.11%	-0.60%
25	-0.10%	-0.55%
30	-0.10%	-0.50%
35	-0.09%	-0.40%
α = Δ Br / Δ T * 100 (Br @ 20°C) [ΔT = 20°C - 100°C] β = Δ Hci / Δ T * 100 (Hci @ 20°C) [ΔT = 20°C - 100°C]

Neodymium Magnets - Physical Properties
Property	Units	Values
Vickers Hardness	Hv	≥550
Density	g/cm3	≥7.4
Curie Temp TC	°C	312 - 380
Curie Temp TF	°F	593 - 716
Specific Resistance	μΩ⋅Cm	150
Bending Strength	Mpa	250
Compressive Strength	Mpa	1000~1100
Thermal Expansion Parallel (∥) to Orientation (M)	°C-1	(3-4) x 106
Thermal Expansion Perpendicular (⊥) to Orientation (M)	°C-1	-(1-3) x 10-6
Young's Modulus	kg/mm2	1.7 x 104

The listed values are approximate and should be used as a reference.  Any magnetic or physical characteristics should be substantiated before selecting a magnet material.  Please engage Dura’s magnet Design / Development team before selecting a design path.

Technical Articles
Making Sense of Neodymium Magnet Grades