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Will High Temperature Demagnetize NdFeB Magnets

Rare earth neodymium-iron-boron (NdFeB) magnets are the most powerful permanent magnets and are widely used in various applications. They are well known for their high magnetic field strength, stability, and consistency. However, one of the most significant concerns about NdFeB magnets is their thermal stability. The high temperature can cause the destruction of the magnet's magnetic field, known as demagnetization, reducing their functionality. Hence, it is essential to understand the effects of high temperature on NdFeB magnets and determine the maximum temperature that they can sustain without demagnetization.

Will High Temperature Demagnetize NdFeB Magnets?

Yes, high temperature can cause NdFeB magnets to demagnetize. The demagnetization of NdFeB magnets is a result of thermal fluctuations in the magnet's magnetic field. Specifically, high temperatures cause more thermal energy to be present, which moves the atoms more rapidly than at lower temperatures. This increased thermal energy creates fluctuations in the magnetic field, leading to a reduced magnetic field strength and, eventually, demagnetization.

What is the Maximum Temperature That NdFeB Magnets Can Withstand Without Demagnetization?

The maximum temperature that NdFeB magnets can withstand without demagnetization is dependent on various factors, such as the magnet's grade, geometry, operating temperature, and duration. The maximum temperature limit is typically specified in the NdFeB magnet's datasheet, but in general, NdFeB magnets can withstand temperatures up to 150°C without a significant reduction in magnetic performance. Moreover, some higher grade NdFeB magnets can tolerate up to 200°C operating temperatures.

Performance

Remanence Induction Intensity (Br)

Magnetic Coercive Force (Hcb)

Intrinsic Coercivity (Hcj)

Maximum Energy Product

Squareness Factors

Maximum Working Temperature

 

 

 

 

(BH)max

(Hk/Hcj)

Tw L/D = 0.7

Grade

Min

Min

Min

Range

Min

 

 

T

kGs

kA/m

kOe

kA/m

kOe

kA/m³

MGOe

%

°c

N28ZH

1.04

10.4

772

9.7

3184

40

207~239

26~30

90

250

N44AH

1.3

13

971

12.2

2786

35

326~358

41~45

90

230

N42AH

1.29

12.9

963

12.1

2786

35

318~350

40~44

90

230

N40AH

1.26

12.6

939

11.8

2786

35

302~334

38~42

90

230

N35AH

1.17

11.7

868

10.9

2786

35

263~295

33~37

90

230

N30AH

1.08

10.8

804

10.1

2786

35

223~255

28~32

90

230

N42TH

1.29

12.9

957

11.8

2627

33

318 ~ 342

43 ~ 46

90

220

N40TH

1.26

12.6

930

11.5

2627

33

302 ~ 326

40 ~ 43

90

220

N38TH

1.23

12.3

910

11.1

2627

33

287 ~ 310

38 ~ 41

90

220

N35TH

1.18

11.8

876

11

2786

35

263 ~ 287

36 ~ 39

90

220

N33TH

1.13

11.3

844

10.6

2786

35

247 ~ 270

33 ~ 36

90

220

N30TH

1.1

11

796

10

2786

35

223 ~ 247

31 ~ 33

90

220

N28TH

1.05

10.5

756

9.5

2786

35

207 ~ 230

25 ~ 29

90

220

N45EH

1.33

13.3

995

12.5

2308

29

342 ~ 366

45 ~ 49

90

200

N42EH

1.29

12.9

957

11.8

2308

29

318 ~ 342

43 ~ 46

90

200

N40EH

1.26

12.6

930

11.5

2388

30

302 ~ 326

40 ~ 43

90

200

N38EH

1.23

12.3

910

11.1

2388

30

287 ~ 310

38 ~ 41

90

200

N35EH

1.18

11.8

876

11

2388

30

263 ~ 287

36 ~ 39

90

200

N33EH

1.13

11.3

844

10.6

2388

30

247 ~ 270

33 ~ 36

90

200

N30EH

1.1

11

796

10

2388

30

223 ~ 247

31 ~ 33

90

200

N28EH

1.05

10.5

756

9.5

2388

30

207 ~ 230

25 ~ 29

90

200

N52UH

1.42

14.2

1018

12.8

1911

24

390 ~ 422

49 ~ 53

90

180

N50UH

1.39

13.9

1018

12.8

1911

24

374 ~ 406

47 ~ 51

90

180

N48UH

1.37

13.7

1018

12.8

1911

24

358 ~ 390

45 ~ 49

90

180

N45UH

1.33

13.3

995

12.5

1911

24

342 ~ 366

45 ~ 49

90

180

N42UH

1.29

12.9

957

11.8

1990

25

318 ~ 342

43 ~ 46

90

180

N40UH

1.26

12.6

930

11.5

1990

25

302 ~ 326

40 ~ 43

90

180

N38UH

1.23

12.3

910

11.1

1990

25

287 ~ 310

38 ~ 41

90

180

N35UH

1.18

11.8

876

11

1990

25

263 ~ 287

36 ~ 39

90

180

N33UH

1.13

11.3

844

10.6

1990

25

247 ~ 270

33 ~ 36

90

180

N30UH

1.1

11

796

10

1990

25

223 ~ 247

31 ~ 33

90

180

N28UH

1.05

10.5

756

9.5

1990

25

207 ~ 230

28 ~ 31

90

180

N52SH

1.42

14.2

1018

12.8

1512

19

390 ~ 422

49 ~ 53

90

150

N50SH

1.39

13.9

1018

12.8

1512

19

374 ~ 406

47 ~ 51

90

150

N48SH

1.37

13.7

1018

12.8

1512

19

358 ~ 390

45 ~ 49

90

150

N45SH

1.33

13.3

995

12.5

1592

20

342 ~ 366

45 ~ 49

90

150

N42SH

1.29

12.9

957

11.8

1592

20

318 ~ 342

43 ~ 46

90

150

N40SH

1.26

12.6

930

11.5

1592

20

302 ~ 326

40 ~ 43

90

150

N38SH

1.23

12.3

910

11.1

1592

20

287 ~ 310

38 ~ 41

90

150

N35SH

1.18

11.8

876

11

1592

20

263 ~ 287

36 ~ 39

90

150

N33SH

1.13

11.3

844

10.6

1592

20

247 ~ 270

33 ~ 36

90

150

N30SH

1.1

11

796

10

1592

20

223 ~ 247

31 ~ 33

90

150

N28SH

1.05

10.5

756

9.5

1592

20

207 ~ 230

28 ~ 31

95

150

N55H

1.45

14.5

1035

13

1274

16

406 ~ 438

53 ~ 56

95

120

N52H

1.42

14.2

1035

13

1274

16

390 ~ 422

49 ~ 53

95

120

N50H

1.39

13.9

1035

13

1274

16

374 ~ 406

47 ~ 51

95

120

N48H

1.37

13.7

1018

12.8

1274

16

358 ~ 390

45 ~ 49

95

120

N45H

1.33

13.3

995

12.5

1353

17

342 ~ 366

45 ~ 49

95

120

N42H

1.29

12.9

957

12

1353

17

318 ~ 342

43 ~ 46

95

120

N40H

1.26

12.6

930

117

1353

17

302 ~ 326

40 ~ 43

95

120

N38H

1.23

12.3

910

11.4

1353

17

287 ~ 310

38 ~ 41

95

120

N35H

1.18

11.8

876

11

1353

17

263 ~ 287

36 ~ 39

95

120

N33H

1.13

11.3

844

10.6

1353

17

247 ~ 270

33 ~ 36

95

120

N30H

1.1

11

796

10

1353

17

223 ~ 247

31 ~ 33

95

120

N28H

1.05

10.5

756

9.5

1353

17

207 ~ 230

28 ~ 31

95

120

N55M

1.45

14.5

995

12.5

1035

13

406 ~ 438

51 ~ 55

95

100

N52M

1.42

14.2

995

12.5

1035

13

390 ~ 422

49 ~ 53

95

100

N50M

1.39

13.9

1035

13

1114

14

374 ~ 406

47 ~ 51

95

100

N48M

1.37

13.7

1012

12.7

1114

14

358 ~ 390

45 ~ 49

95

100

N45M

1.33

13.3

971

12.2

1114

14

342 ~ 366

43 ~ 46

95

100

N42M

1.29

12.9

938

11.8

1114

14

318 ~ 342

40 ~ 43

95

100

N40M

1.26

12.6

910

11.4

1114

14

302 ~ 326

38 ~ 41

95

100

N38M

1.23

12.3

876

11

1114

14

287 ~ 310

36 ~ 39

95

100

N35M

1.18

11.8

860

10.8

1114

14

263 ~ 287

33 ~ 36

95

100

N33M

1.13

11.3

796

10

1114

14

247 ~ 270

31 ~ 33

95

100

N30M

1.1

11

796

10

1114

14

223 ~ 247

28 ~ 31

95

100

N28M

1.05

10.5

756

9.5

1114

14

207 ~ 230

26 ~ 29

95

100

N55

1.45

14.5

836

10.5

875

11

406 ~ 438

51 ~ 55

95

80

N54

1.45

14.5

836

10.5

876

11

406 ~ 438

51 ~ 55

95

80

N52

1.42

14.2

860

10.8

960

12

390 ~ 422

49 ~ 53

95

80

N50

1.39

13.9

860

10.8

960

12

374 ~ 406

47 ~ 51

95

80

N48

1.37

13.7

860

10.8

960

12

358 ~ 390

45 ~ 49

95

80

N45

1.33

13.3

836

10.5

960

12

342 ~ 366

43 ~ 46

95

80

N42

1.29

12.9

836

10.5

960

12

318 ~ 342

40 ~ 43

95

80

N40

1.26

12.6

836

10.5

960

12

302 ~ 326

38 ~ 41

95

80

N38

1.23

12.3

836

10.5

960

12

287 ~ 310

36 ~ 39

95

80

N35

1.18

11.8

836

10.5

960

12

263 ~ 287

33 ~ 36

95

80

N33

1.13

11.3

796

10

960

12

247 ~ 270

31 ~ 34

95

80


The Impact of Coatings on NdFeB Magnets' Demagnetization at High Temperature

NdFeB magnets are highly susceptible to corrosion and are therefore coated with various materials to protect them from the environment. While these coatings can help protect the magnets from corrosion, they can also affect the magnet's performance at high temperatures. For example, some coatings, such as epoxy, can melt and cause the magnet to demagnetize much earlier than expected. One of the most commonly used coatings for NdFeB magnets is the nickel-copper-nickel (Ni-Cu-Ni) coating, which can withstand temperatures up to 200°C. Other coatings that can tolerate high temperatures include gold, silver, and tin.

NdFeB magnets are sensitive to high temperatures, and demagnetization can occur at temperatures above their maximum operating temperature range. The maximum temperature that NdFeB magnets can tolerate without demagnetization is typically specified in the magnet's datasheet and is dependent on various factors that affect the magnets' performance. Therefore, it is essential to consider the application's operating temperature and duration and select the appropriate coating for the magnet. With careful consideration of these factors, NdFeB magnets can be used effectively in high temperature applications without demagnetization.

If you couldn’t make sure which grade of magnet should be used,could consult with Zhejiang Zhongke magnetic Industry Co.,Ltd. team,they will advise you the proper material grade and provide you professional suggestions.