Physical properties of neodymium magnets

Neodymium magnets are made from a compound of neodymium, iron and boron Nd₂Fe₁₄B. This material is characterized by very high remanence and maximum energy product, which makes neodymium the strongest type of magnet in the world. At the same time, they are very resistant to demagnetisation by external magnetic fields.

The weak aspect of neodymium magnets is low temperature resistance and fragility. The material Nd₂Fe₁₄B also chemically reacts with oxygen in the air, and therefore all magnets must be covered protective layer of chemically more stable material. It is usually nickel, zinc, epoxy resin, plastic or rubber.

In this article you will find an overview of the most important physical properties of neodymium magnets.

Temperature resistance

The neodymium magnet material can be described by the abbreviation NČČPP, where:

• N means it is a neodymium magnet
• ČČ is a two-digit number from 28 to 55. It represents the maximum energy product in MGOe units. The higher the number, the stronger the magnet.
• PP is a pair of letters that determines the heat resistance of the magnet.

When a neodymium magnet is heated above its maximum working temperature, it begins to permanently lose magnetic strength. The more you heat it up, the more percentage of its power it loses. The Curie temperature is the temperature at which the magnet has no strength left.

Both the maximum working temperature and the Curie temperature depend on the PP suffix:

PP suffix	Maximum working temperature	Curie temperature
without suffix	80 °C	310 °C
M	100 °C	320 °C
H	120 °C	320 – 350 °C
SH	150 °C	340 – 360 °C
UH	180 °C	350 – 380 °C
EH	200 °C	350 – 380 °C
AH	240 °C	350 – 380 °C

The data in the table is only a rough estimate. Temperature resistance also depends on the shape of the magnet and its surroundings. More in the article about high and low temperatures.

Magnetic properties

The properties of the most commonly used materials are listed.

Material	Remanence (Br)		Coercive force (Hc)				Max. energy product (BH)max
			Normal (Hcb)		Internal (Hci)
	mT	kGs	kA/m	kOe	kA/m	kOe	kJ/m3	MGOe
N30	1080-1130	10.8-11.3	≥796	≥10	≥955	≥12	233-247	28-31
N33	1130-1170	11.3-11.7	≥836	≥10.5	≥955	≥12	247-271	31-34
N35	1170-1220	11.7-12.2	≥868	≥10.9	≥955	≥12	263-287	33-36
N38	1220-1250	12.2-12.5	≥899	≥11.3	≥955	≥12	287-310	36-39
N40	1250-1280	12.5-12.8	≥907	≥11.4	≥955	≥12	302-326	38-41
N42	1280-1320	12.8-13.2	≥915	≥11.5	≥955	≥12	318-342	40-43
N45	1320-1380	13.2-13.8	≥923	≥11.6	≥955	≥12	342-366	43-46
N48	1380-1420	13.8-14.2	≥836	≥10.5	≥955	≥12	366-390	46-49
N50	1400-1450	14.0-14.5	≥796	≥10.0	≥876	≥11	382-406	48-51
N52	1430-1480	14.3-14.8	≥796	≥10.0	≥876	≥11	398-422	50-53
N55	1450-1510	14.5-15.1	≥796	≥10.0	≥876	≥11	406-438	52-55
M
N30M	1080-1130	10.8-11.3	≥796	≥10	≥1114	≥14	223-247	28-31
N33M	1130-1170	11.3-11.7	≥836	≥10.5	≥1114	≥14	247-263	31-33
N35M	1170-1220	11.7-12.2	≥868	≥10.9	≥1114	≥14	263-287	33-36
N38M	1220-1250	12.2-12.5	≥899	≥11.3	≥1114	≥14	287-310	36-39
N40M	1250-1280	12.5-12.8	≥923	≥11.6	≥1114	≥14	302-326	38-41
N42M	1280-1320	12.8-13.2	≥955	≥12.0	≥1114	≥14	318-342	40-43
N45M	1320-1380	13.2-13.8	≥955	≥12.5	≥1114	≥14	342-366	43-46
N48M	1360-1430	13.6-14.3	≥1027	≥12.9	≥1114	≥14	366-390	46-49
N50M	1400-1450	14.0-14.5	≥1033	≥13.0	≥1114	≥14	382-406	48-51
H
N30H	1080-1130	10.8-11.3	≥796	≥10.0	≥1353	≥17	223-247	28-31
N33H	1130-1170	11.3-11.7	≥836	≥10.5	≥1353	≥17	247-271	31-34
N35H	1170-1220	11.7-12.2	≥868	≥10.9	≥1353	≥17	263-287	33-36
N38H	1220-1250	12.2-12.5	≥899	≥11.3	≥1353	≥17	287-310	36-39
N40H	1250-1280	12.5-12.8	≥923	≥11.6	≥1353	≥17	302-326	38-41
N42H	1280-1320	12.8-13.2	≥955	≥12.0	≥1353	≥17	318-342	40-43
N45H	1320-1360	13.2-13.6	≥963	≥12.1	≥1353	≥17	342-366	43-46
N48H	1370-1430	13.7-14.3	≥995	≥12.5	≥1353	≥17	366-390	46-49
SH
N30SH	1080-1130	10.8-11.3	≥804	≥10.1	≥1592	≥20	223-247	28-31
N33SH	1130-1170	11.3-11.7	≥844	≥10.6	≥1592	≥20	247-271	31-34
N35SH	1170-1220	11.7-12.2	≥876	≥11.0	≥1592	≥20	263-287	33-36
N38SH	1220-1250	12.2-12.5	≥907	≥11.4	≥1592	≥20	287-310	36-39
N40SH	1250-1280	12.5-12.8	≥939	≥11.8	≥1592	≥20	302-326	38-41
N42SH	1280-1320	12.8-13.2	≥987	≥12.4	≥1592	≥20	318-342	40-43
N45SH	1320-1380	13.2-13.8	≥1003	≥12.6	≥1592	≥20	342-366	43-46
UH
N28UH	1020-1080	10.2-10.8	≥764	≥9.6	≥1990	≥25	207-231	26-29
N30UH	1080-1130	10.8-11.3	≥812	≥10.2	≥1990	≥25	223-247	28-31
N33UH	1130-1170	11.3-11.7	≥852	≥10.7	≥1990	≥25	247-271	31-34
N35UH	1180-1220	11.8-12.2	≥860	≥10.8	≥1990	≥25	263-287	33-36
N38UH	1220-1250	12.2-12.5	≥876	≥11.0	≥1990	≥25	287-310	36-39
N40UH	1250-1280	12.5-12.8	≥899	≥11.3	≥1990	≥25	302-326	38-41
EH
N28EH	1040-1090	10.4-10.9	≥780	≥9.8	≥2388	≥30	207-231	26-29
N30EH	1080-1130	10.8-11.3	≥812	≥10.3	≥2388	≥30	223-247	28-31
N33EH	1130-1170	11.3-11.7	≥836	≥10.5	≥2388	≥30	247-271	31-34
N35EH	1170-1220	11.7-12.2	≥876	≥11.0	≥2388	≥30	263-287	33-36
N38EH	1220-1250	12.2-12.5	≥899	≥11.3	≥2388	≥30	287-310	36-39
AH
N28AH	1040-1090	10.4-10.9	≥787	≥9.9	≥2624	≥33	207-231	26-29
N30AH	1080-1130	10.8-11.3	≥819	≥10.3	≥2624	≥33	223-247	28-31
N33AH	1130-1170	11.3-11.7	≥843	≥10.6	≥2624	≥33	247-271	31-34

The table uses units of kilogauss (kGs), kilooersted (kOe) and megagauss-oersted (MGOe), as well as Tesla (T), kiloampere per metre (kA/m) or kilojoules per cubic metre (kA/m) – depending on which one(s) you need to use. The following relationships apply between these units:

• T = 10 kGs
• kA/m = 0.01257 KOe
• MGOe = 0.1257 kJ/m³

Mechanical and other properties

Quantity	Value
Density	7.4-7.5 g/cm3
Thermal capacity	350-500 J/(kg.°C)
Coefficient of thermal expansion in the magnetisation direction	5.2 x 10-6 /°C
Coefficient of thermal expansion perpendicular to the magnetisation direction	-0.8 x 10-6 /°C
Compressive strength	950 MPa
Tensile strength	80 MPa
Vickers hardness test	560-600
Young’s modulus	160 GPa

Are you looking for a suitable magnet?

If you need advice on choosing a suitable magnet for your use, contact us at info@orodian.com or call +421 940 640 600. We will help you choose a magnet from our offer or we can make custom magnets.

Other articles

• Magnetic calculator – calculate the strength of a magnet
• Effect of temperature on neodymium magnets
• How to shield the magnetic field