Neodymium magnets are dark gray alloy. They are composed of Neodymium, Iron and Boron. Density of Neodymium magnets is .27Lb/in3 (7.5g/cm3).
Neodymium magnets are manufactured in a metallurgy process through alloying, crushing, powdering, pressing w/magnetic orientation, sintering, then cutting, coating, inspecting and packing before shipment.

Neodymium magnets offer the highest (BH)max and high Hci
(BH)max, the Maximum Energy Product, of Neodymium magnets is highest of any kind of permanent magnets today in the world. (BH)max at different grades of Neodymium magnets is 27 to 52 MGOe.

Neodymium magnets have extremely resistance to demagnetization with Hci, Intrisic coercive force, over 12,000 Oe.
Because of very high (BH)max and Hci, Neodymium magnets could be used as a reversible medium for large amount of energy transformation in miniaturized application where a strong magnetic demagnetization field exists , such as computer hard drive.
Armstrong Magnetics N40 Neodymium magnets in disk and rectangle shapes for customers' immediate needs and accept special orders for custom Neodymium magnets.

Neodymium magnets are most powerful of any kind of magnetic materials
Br of Neodymium magnets are much more than 11,000 Gauss. Therefore, Neodymium magnets have strong holding strength on metal surface and could be used as component for holding, separating, etc.
Neodymium magnets must be carefully handled to avoid personal injury and material damage due to its extremely magnetic strength and brittle property.

Neodymium magnets are sensitive to temperature change and even lose magnet properties at high temperature
Neodymium magnets lose -0.09 ~ -0.13% of Br/°C and can work stably under 80°C for low Hci Neodymium magnets and 150°C for high Hci Neodymium magnets.

Neodymium magnets are corrupted in humid environment
Surface protection is strongly recommended, such as plating, varnishing and encapsulating.

Neodymium magnets are hard and brittle
Neodymium magnets can be abrasively machined with coolant served to absorb heating and dust. Without coolant, rare earth magnets could crack and chip by the heat produced during high speed cutting or grinding, and the sparks contain the easily oxidized grinding dust that could cause fire!

Tolerance of Neodymium magnets
Unless otherwise specified, tolerance on dimension of magnetization is ±.005”. Other dimensions are ±1.5% or ±.010”, whichever is greater.

MAGNETIC PROPERTY OF NEODYMIUM MAGNET

Grade	Remanence Br		Coercive Force Hcb		Intrinsic Coercive force Hci		Max Energy Product (BH) max		Max Working Temp.
Grade	KG	T	KOe	KA/m	KOe	KA/m	MGOe	KJ/m	℃	°F
N35	11.4-11.8	1.18-1.28	≥ 10.8	≥ 836	≥ 12	≥ 955	33-36	263-287	80	176
N38	11.8-12.3	1.18-1.28	≥ 10.8	≥ 860	≥ 12	≥ 955	36-39	287-310	80	176
N40	12.7-12.9	1.27-1.29	≥ 11.0	≥ 876	≥ 12	≥ 955	38-41	303-326	80	176
N42	12.9-13.3	1.29-1.33	≥ 10.5	≥ 836	≥ 12	≥ 955	40-43	318-342	80	176
N45	13.3-13.8	1.33-1.38	≥ 9.5	≥ 756	≥ 12	≥ 955	43-46	342-366	80	176
N48	13.8-14.2	1.38-1.42	≥ 10.5	≥ 835	≥ 12	≥ 955	46-49	366-390	80	176
N50	13.8-14.5	1.38-1.45	≥ 10.5	≥ 835	≥ 11	≥ 955	47-51	374-406	80	176
N52	14.3-14.8	1.43-1.48	≥ 10.8	≥ 860	≥ 11	≥ 876	50-53	398-422	80	176
33M	11.4-11.8	1.14-1.18	≥ 10.3	≥ 820	≥ 14	≥ 1114	31-33	247-263	100	212
35M	11.8-12.3	1.18-1.23	≥ 10.8	≥ 860	≥ 14	≥ 1114	33-36	263-287	100	212
38M	12.3-12.7	1.23-1.27	≥ 11.0	≥ 876	≥ 14	≥ 1114	38-41	303-326	100	212
40M	12.7-12.9	1.27-1.29	≥ 11.4	≥ 907	≥ 14	≥ 1114	38-41	303-326	100	212
42M	12.8-13.2	1.28-1.32	≥ 11.6	≥ 923	≥ 14	≥1114	40-43	318-342	100	212
45M	13.2-13.8	1.32-1.38	≥ 11.8	≥ 939	≥ 14	≥ 1114	43-46	342-366	100	212
48M	13.6-14.0	1.36-1.40	≥ 11.8	≥ 939	≥ 14	≥ 1114	46-49	366-390	100	212
50M	14.0-14.5	1.40-1.45	≥ 13.0	≥ 1033	≥ 14	≥ 1114	48-51	382-406	100	212
30H	10.8-11.4	1.08-1.14	≥ 10.2	≥ 812	≥ 17	≥ 1353	28-31	223-247	120	212
33H	11.4-11.8	1.14-1.18	≥ 10.6	≥ 844	≥ 17	≥ 1353	31-33	247-263	120	212
35H	11.8-12.3	1.18-1.28	≥ 11.0	≥ 876	≥ 17	≥ 1353	33-36	263-287	120	212
38H	12.3-12.7	1.23-1.27	≥ 11.2	≥ 890	≥ 17	≥ 1353	36-39	287-310	120	212
40H	12.7-12.9	1.27-1.29	≥ 11.5	≥ 915	≥ 17	≥ 1353	38-41	303-326	120	212
42H	12.8-13.2	1.28-1.32	≥ 12.0	≥ 955	≥ 17	≥ 1353	40-43	318-342	120	212
45H	13.2-13.5	1.32-1.38	≥ 12.0	≥ 955	≥ 17	≥ 1353	42-46	335-366	120	212
46H	13.3-13.8	1.33-1.38	≥ 12.2	≥ 972	≥ 16	≥ 1274	44-47	350-374	120	212
48H	13.6-14.3	1.36-1.43	≥ 12.5	≥ 995	≥ 16	≥ 1274	46-49	366-390	120	212
30SH	10.8-11.4	1.081.14	≥ 10.0	≥ 796	≥ 20	≥ 1672	28-31	223-247	150	302
33SH	11.4-11.8	1.14-1.18	≥ 10.5	≥ 836	≥ 20	≥ 1672	31-34	247-276	150	302
35SH	11.8-12.3	1.18-1.23	≥ 11.0	≥ 876	≥ 20	≥ 1672	33-36	263-287	150	302
38SH	12.3-12.7	1.23-1.27	≥ 11.4	≥ 907	≥ 20	≥ 1972	36-39	287-310	150	302
40SH	12.5-12.8	1.25-1.28	≥ 11.8	≥ 939	≥ 20	≥ 1972	38-41	302-326	150	302
42SH	12.8-13.2	1.28-1.32	≥ 11.8	≥ 939	≥ 20	≥ 1672	40-43	320-343	150	302
45SH	13.2-13.8	1.32-1.38	≥ 12.6	≥ 1003	≥ 20	≥ 1592	43-46	342-366	150	302
30UH	10.8-11.4	1.08-1.14	≥ 10.2	≥ 812	≥ 25	≥ 1990	28-31	223-247	180	356
33UH	11.3-11.7	1.13-1.17	≥ 10.7	≥ 852	≥ 25	≥ 1990	31-33	247-263	180	356
35UH	11.7-12.1	1.17-1.21	≥ 10.7	≥ 852	≥ 25	≥ 1990	33-36	263-287	180	356
38UH	12.1-12.5	1.21-1.25	≥ 11.4	≥ 907	≥ 25	≥ 1990	36-39	287-310	180	356
40UH	12.5-12.8	1.25-1.28	≥ 11.4	≥ 907	≥ 25	≥ 1990	38-41	302-326	180	356
28EH	10.5-10.8	1.05-1.08	≥ 9.5	≥ 756	≥ 30	≥ 2388	26-29	207-231	200	392
30EH	10.8-11.4	1.08-1.14	≥ 9.5	≥ 756	≥ 30	≥ 2388	28-31	223-241	200	292
33EH	11.3-11.7	1.13-1.17	≥ 10.2	≥ 812	≥ 30	≥ 2388	31-33	247-263	200	392
35EH	11.7-12.1	1.17-1.21	≥ 10.2	≥ 812	≥ 30	≥ 2388	33-36	263-287	200	392
38EH	12.1-12.5	1.21-1.25	≥ 11.4	≥ 907	≥ 30	≥ 2388	36-39	287-310	200	392
30AH	10.8-11.3	1.08-1.13	≥ 10.2	≥ 812	≥ 35	≥ 2785	28-32	223-255	220	428
33AH	11.2-11.7	1.12-1.17	≥ 10.2	≥ 812	≥ 35	≥ 2785	31-34	247-271	220	428

Note:
1. The data above are tested at 20ºC.
2. The maximum working temperature for a given magnet could be less due to the ratio of length and diameter of the magnet, the structure of its assembly with steel parts and environmental factors.
3. A strong external adverse magnetic field, shock, vibration and elctro-magnetic field can result in partial demagnetization.