General introduction of sintered neodymium magnets (NdFeB)

Sintered magnets are those ones of the high performance rare earth permanent magnets, which use neodymium (Nd), iron (Fe), and boron (B) as their main ingredients and is susceptible to demagnetization when exposed to elevated temperatures. There are many grades which can withstand high temperatures, but several factors will dictate the performance of the neodymium magnet. There are sintered NdFeB, sintered AlNiCo, sintered SmCo and sintered ferrites.

We know the professional manufacturers and suppliers of sintered neodymium magnets in China.

Neodymium magnets have the following characteristics:

  • super strong Br Resident induction
  • excellent demagnetization resistance capability
  • good price relative to its high magnetic properties
  • coating is needed for NdFeB generally (metallic zinc, nickel, nickel+nickel, copper+nickel, nickel+copper+nickel, gold, organic epoxy, nickel+epoxy coating)
  • some manufacturers with corresponding technologies are even able to provide uncoated corrosion stable magnets


What shapes can be formed with neodymium magnets?

example Neodymium Magnets (NdFeB)   example Neodymium Magnets (NdFeB)
NdFeB magnets for motors and generators, tile-shaped and special-shaped NdFeB magnet in various specification
 
example Neodymium Magnets (NdFeB)   example Neodymium Magnets (NdFeB)
NdFeB blocks in various specification, NdFeB products painted with epoxy resin
 
example Neodymium Magnets (NdFeB)   example Neodymium Magnets (NdFeB)
NdFeB rings in various specification, NdFeB cylinders in various specification
 
example Neodymium Magnets (NdFeB)   example Neodymium Magnets (NdFeB)
special shape of NdFeB magnet, rubber coated NdFeB magnet
 
example Neodymium Magnets (NdFeB)
special shape of NdFeB magnet

 

Magnetic properties of neodymium magnets:

Grade

Remanence

Coercive Force

Intrinsic Coercive Force

Max. energy product

Max.
Operating
Temperature

Br
mT
(kGs)

Hcb
kA/m
(kOe)

Hcj
kA/m
(kOe)

( BH ) max kJ/m 3
(MGOe)

Tw
"L/D=0.7"

N35

1170-1220
(11.7-12.2)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

263-287
(33-36)

80 ℃

N38

1220-1260
(12.2-12.6)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

287-303
(36-38)

80 ℃

N40

1260-1290
(12.6-12.9)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

303-318
(38-40)

80 ℃

N42

1290-1330
(12.9-13.3)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

318-334
(40-42)

80 ℃

N45

1330-1370
(13.3-13.7)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

334-358
(42-45)

80 ℃

N48

1360-1420
(13.6-14.2)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

358-382
(45-48)

80 ℃

N50

1410-1450
(14.1-14.5)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

382-398
(48-50)

80 ℃

N52

1440-1480
(14.4-14.8)

≥ 876
(≥ 11.0)

≥ 955
(≥ 12.0)

394-414
(49.5-52)

80 ℃

N35M

1170-1220
(11.7-12.2)

≥ 892
(≥ 11.2)

≥ 1114
(≥ 14.0)

263-287
(33-36)

100 ℃

N38M

1220-1260
(12.2-12.6)

≥ 907
(≥ 11.4)

≥ 1114
(≥ 14.0)

287-303
(36-38)

100 ℃

N40M

1260-1290
(12.6-12.9)

≥ 907
(≥ 11.4)

≥ 1114
(≥ 14.0)

303-318
(38-40)

100 ℃

N42M

1290-1330
(12.9-13.3)

≥ 907
(≥ 11.4)

≥ 1114
(≥ 14.0)

318-334
(40-42)

100 ℃

N45M

1330-1370
(13.3-13.7)

≥ 907
(≥ 11.4)

≥ 1114
(≥ 14.0)

334-358
(42-45)

100 ℃

N48M

1360-1420
(13.6-14.2)

≥ 907
(≥ 11.4)

≥ 1114
(≥ 14.0)

358-382
(45-48)

100 ℃

N50M

1410-1450
(14.1-14.5)

≥ 907
(≥ 11.4)

≥ 1114
(≥ 14.0)

382-398
(48-50)

100 ℃

N33H

1140-1170
(11.4-11.7)

≥ 820
(≥ 10.3)

≥ 1353
(≥ 17.0)

247-263
(31-33)

120 ℃

N35H

1170-1220
(11.7-12.2)

≥ 860
(≥ 10.8)

≥ 1353
(≥ 17.0)

263-287
(33-36)

120 ℃

N38H

1220-1260
(12.2-12.6)

≥ 907
(≥ 11.4)

≥ 1353
(≥ 17.0)

287-303
(36-38)

120 ℃

N40H

1260-1290
(12.6-12.9)

≥ 907
(≥ 11.4)

≥ 1353
(≥ 17.0)

303-318
(38-40)

120 ℃

N42H

1290-1330
(12.9-13.3)

≥ 907
(≥ 11.4)

≥ 1353
(≥ 17.0)

318-334
(42-40)

120 ℃

N45H

1330-1370
(13.3-13.7)

≥ 907
(≥ 11.4)

≥ 1353
(≥ 17.0)

342-358
(42-45)

120 ℃

N48H

1360-1420
(13.6-14.2)

≥ 907
(≥ 11.4)

≥ 1353
(≥ 17.0)

358-382
(45-48)

120 ℃

N30SH

1080-1140
(10.8-11.4)

≥ 804
(≥ 10.1)

≥ 1592
(≥ 20.0)

223-239
(28-30)

150 ℃

N30SH
*(T-series)

1080-1140
(10.8-11.4)

≥ 804
(≥ 10.1)

≥ 1831
(≥ 23.0)

223-239
(28-30)

150 ℃

N33SH

1140-1170
(11.4-11.7)

≥ 820
(≥ 10.3)

≥ 1592
(≥ 20.0)

239-263
(30-33)

150 ℃

N33SH
*(T-series)

1140-1170
(11.4-11.7)

≥ 820
(≥ 10.3)

≥ 1831
(≥ 23.0)

239-263
(30-33)

150 ℃

N35SH

1170-1220
(11.7-12.2)

≥ 860
(≥ 10.8)

≥ 1592
(≥ 20.0)

263-287
(33-36)

150 ℃

N35SH
*(T-series)

1170-1220
(11.7-12.2)

≥ 860
(≥ 10.8)

≥ 1831
(≥ 23.0)

263-287
(33-36)

150 ℃

N38SH

1220-1260
(12.2-12.6)

≥ 907
(≥ 11.4)

≥ 1592
(≥ 20.0)

287-303
(36-38)

150 ℃

N38SH
*(T-series)

1220-1260
(12.2-12.6)

≥ 907
(≥ 11.4)

≥ 1831
(≥ 23.0)

287-303
(36-38)

150 ℃

N40SH

1260-1290
(12.6-12.9)

≥ 907
(≥ 11.4)

≥ 1592
(≥ 20.0)

303-318
(38-40)

150 ℃

N40SH
*(T-series)

1260-1290
(12.6-12.9)

≥ 907
(≥ 11.4)

≥ 1831
(≥ 23.0)

303-318
(38-40)

150 ℃

N42SH

1290-1330
(12.9-13.3)

≥ 907
(≥ 11.4)

≥ 1592
(≥ 20.0)

318-334
(40-42)

150 ℃

N42SH
*(T-series)

1290-1330
(12.9-13.3)

≥ 907
(≥ 11.4)

≥ 1831
(≥ 23.0)

318-334
(40-42)

150 ℃

N45SH

1330-1390
(13.3-13.9)

≥ 907
(≥ 11.4)

≥ 1592
(≥ 20.0)

334-358
(42-45)

150 ℃

N45SH
*(T-series)

1330-1390
(13.3-13.9)

≥ 907
(≥ 11.4)

≥ 1831
(≥ 23.0)

334-358
(42-45)

150 ℃

N30UH

1080-1140
(10.8-11.4)

≥ 804
(≥ 10.1)

≥ 1990
(≥ 25.0)

223-239
(28-30)

180 ℃

N30UH
*(T-series)

1080-1140
(10.8-11.4)

≥ 804
(≥ 10.1)

≥ 2149
(≥ 27.0)

223-239
(28-30)

180 ℃

N33UH

1140-1170
(11.4-11.7)

≥ 820
(≥ 10.3)

≥ 1990
(≥ 25.0)

239-263
(30-33)

180 ℃

N33UH
*(T-series)

1140-1170
(11.4-11.7)

≥ 820
(≥ 10.3)

≥ 2149
(≥ 27.0)

239-263
(30-33)

180 ℃

N35UH

1170-1220
(11.7-12.2)

≥ 860
(≥ 10.8)

≥ 1990
(≥ 25.0)

263-287
(33-36)

180 ℃

N35UH
*(T-series)

1170-1220
(11.7-12.2)

≥ 860
(≥ 10.8)

≥ 2149
(≥ 27.0)

263-287
(33-36)

180 ℃

N38UH

1220-1260
(12.2-12.6)

≥ 907
(≥ 11.4)

≥ 1990
(≥ 25.0)

287-303
(36-38)

180 ℃

N38UH
*(T-series)

1220-1260
(12.2-12.6)

≥ 907
(≥ 11.4)

≥ 2149
(≥ 27.0)

287-303
(36-38)

180 ℃

N40UH

1260-1290
(12.6-12.9)

≥ 907
(≥ 11.4)

≥ 1990
(≥ 25.0)

303-318
(38-40)

180 ℃

N40UH
*(T-series)

1260-1290
(12.6-12.9)

≥ 907
(≥ 11.4)

≥ 2149
(≥ 27.0)

303-318
(38-40)

180 ℃

N42UH

1290-1330
(12.9-13.3)

≥ 907
(≥ 11.4)

≥ 1990
(≥ 25.0)

318-326
(40-42)

180 ℃

N42UH
*(T-series)

1290-1330
(12.9-13.3)

≥ 907
(≥ 11.4)

≥ 2149
(≥ 27.0)

318-326
(40-42)

180 ℃

N28EH

1040-1080
(10.4-10.8)

≥ 780
(≥ 9.8)

≥ 2388
(≥ 30.0)

207-223
(26-28)

200 ℃

N30EH

1080-1140
(10.8-11.4)

≥ 804
(≥ 10.1)

≥ 2388
(≥ 30.0)

223-239
(28-30)

200 ℃

N33EH

1140-1170
(11.4-11.7)

≥ 820
(≥ 10.3)

≥ 2388
(≥ 30.0)

239-263
(30-33)

200 ℃

N35EH

1170-1220
(11.7-12.2)

≥ 860
(≥ 10.8)

≥ 2388
(≥ 30.0)

263-287
(33-36)

200 ℃

N38EH

1220-1260
(12.2-12.6)

≥ 915
(≥ 11.5)

≥ 2388
(≥ 30.0)

287-303
(36-38)

200 ℃

N28AH

1040-1080
(10.4-10.8)

≥ 780
(≥ 9.8)

≥ 2706
(≥ 34)

207-223
(26-28)

230 ℃

N30AH

1080-1140
(10.8-11.4)

≥ 780
(≥ 9.8)

≥ 2706
(≥ 34)

223-239
(28-30)

230 ℃

N33AH

1140-1170
(11.4-11.7)

≥ 780
(≥ 9.8)

≥ 2706
(≥ 34)

239-263
(30-33)

230 ℃

Note:
Working temperature is tested under 20°C ± 2°C, the inevitable loss of magnetic force is no more than 5%. * T-series can be produced with higher Intrinsic Coercive Force (Hcj) while other parameters stay constant.


Typical physical properties of NdFeB:

Parameter
Unit
Standard Data

Curie Temperature (Tc)

°C

310 - 380

Maximum Operating Temperature (Tw)

°C

80 - 230

Hardness

Hv

620

Electrical Resistivity (p)

Ω.cm

1.8X10 ⁻⁴ - 2.0X10 ⁻⁴

Density (D)

g/cm³

7.45 - 7.65

Recoil Permeability
1.05

Magnetization Field Strength (Hs)

KOe
KA/m

≥ 30
≥ 2400

Bending Strength
Mpa
295 - 345
Tem. Coefficient of Br (α Br)
%/°C
-0.11 - -0.12

Temp. Coefficient of Hcj (β Hcj)

%/°C

-0.5 - -0.7



 

Surface plating of neodymium magnets:

Various coatings are available: Zn, NiCuNi, chemical Ni, NiCu+eboxy, P+eboxy, passivation, Sn

Plating Type
Plating Thikness
Colour
Working Temperature
Salt Spray Test
PCT
Characteristic
Nickel
10-30 µ m
Bright Silver
≤ 200°C
≥ 96 hr
≥ 48 hr
Good performance under salt spray test and constant temperature & humidity test. Suitable for clean enviroments.
Zinc
5-10 µ m
Dark Silver
≤ 160°C
≥ 48 hr
--
Suitable for common enviorments.
Eboxy
10-30 µ m
Char Silver
≤ 120°C
≥ 500 hr
--
Good performance under salt spray test and constant temperature & humidity

 

Note: For different products, the salt spray test and PCT time varies with the shape of the product.

Anti corrosion NdFeB magnets:

Besides above named surface platings some of our manufacturer/ supplier offer also anti corrosion NdFeB magnets. This type can be realized in a special production process.

The magnets can optain a performance under H.A.S.T. test (130°C, 95% Humidity, 2.7 Bar atmospheric pressure for 7 days) a weight loss being less than 1 mg/cm².

surface coating - weight loss diagramm NdFeB
high corrosion resistance NdFeB magnet material traditional NdFeB magnet material