Sintered NdFeB Magnets

Sintered NdFeb Magnets

Shelf time:2019-01-09
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NdFeB Magnets

Neodymium magnets can be divided into three main groups:
1.Regular Neodymium Magnets
2.High corrosion resistant Neodymium Magnets
3.Bonded Neodymium (Isotropic): Manufactured by the injection of plastic material and Neodymium into a mold. This production method yields a very precise magnet which does not require further grinding and does not suffer substantial current loss.

High Corrosion Resistant Magnets

Under the Environment of high temperature, high pressure and high humidity, the weight loss level of uncoated magnets can qualitatively reflect its serving life clearly. Referring to the standard IEC68-2-66 and after 20 days, Hast testing, weight loss of less than 2mg/cm² is available for Precision Magtech, which is the top level worldwide.

Weight loss of Precision Magtech in  a Hast-Test ( 130℃, 95% relative humidity 2.7bar in vapor)?

Glued NdFeB Magnets

NdFeB magnets could be glued in any sizes depends on customers requests, there is a max Isolation Resistance requests, glue gap thickness etc, and how to test the isolation resistance as below.

Advantages and Disadvantages

Advantages and Disadvantages of NdFeB Permanent Magnets

1) Is the strongest magnetic of permanent magnets, has the high energy (BH value) and good coercive force.
2) Manufacturing by the the vacuum sintering process, process maturity;small dimensions,have the good performances and prices; energy (BH value) of NdFeB magnets is more than ten times higher than Ferrites, it is the strongest magnetic materials in the world today, have “magnetic king”reputation.
3) Using the cutting process after sintering,according to the requirements,by the rapid processing, they can be cutted into square,disc.,ring,segment(like tile shape),and so on;Dimension tolerance is commonly +/-0.05mm,if special request,it can be controlled within 0.05mm range by increasing grinding; If requesting the higher process,using the fast quenching scales manufacturing Nd-Fe-B binding NdFeB1988,the precision of dimensions can be reached 0.01mm,but because the organic binder content cause the low energy product,and the much higher cost of forming dies.
4) NdFeB permanent magnets are easy to be rusted/oxided, so their surface should be done eletroplating treatment, such as galvanized(Zn coating), Nickel+copper+nickel, and so on, generally, it requests more than 48hours in Salt-spray test; also can be passivated treament to slow down its oxidative speed; if using the vacuum plating aluminum + electrophoresis epoxy resin, it can go through more than 96hours in Salt-spray condition.

Comparison Permanent Magnets

Basic Performance Comparison Table of Permanent Magnets

Magnets BHmax(MGOe)Max.Working Temp.(0C) Corrosion Resistance Magnetic Performance Material Price Coercive Force Processing Charateristics Composite Index
Sintered NdFeB 26-52 ≤200 C A+ B- A+ B+ 70
SmCo 2:17 22-30 ≤300 A A C- A C 64
SmCo 1: 5 16-25 ≤250 A A- C A- C 62
Bonded NdFeB 5/12 <150 B- B C A+ - 68
AlNiCo <10 <550 A+ B B C- C 54
Sintered Ferrite 3-4.5 < 350 A C A B- B 64
Bonded Ferrite 2-3 < 150 A C B B- - 66
Rubber 0.7/1.6 <85 B C B+ C A 56




Magnetic Properties

Grade Br HcB Hcj (BH )max Max Working Temperature
KGs T KOe KA/m KOe KA/m MGOe KJ/m 3 L/D=0.7
Max Min Max Min Min Min Min Min Max Min Max Min
N33 11.8 11.3 1.18 1.13 ≥10.5 ≥836 ≥12 ≥955 34 31 271 247 ≤80
N35 12.3 11.8 1.23 1.18 ≥10.9 ≥866 ≥12 ≥955 36 33 287 263 ≤80
N38 12.6 12.3 1.26 1.23 ≥11.3 ≥899 ≥12 ≥955 39 36 311 287 ≤80
N40 12.9 12.6 1.29 1.26 ≥11.4 ≥90 ≥12 ≥955 41 38 327 302 ≤80
N42 13.3 12.9 1.33 1.29 ≥11.5 ≥915 ≥12 ≥955 43 40 342 318 ≤80
N45 13.7 13.3 1.37 1.33 ≥11.0 ≥876 ≥12 ≥955 46 43 366 342 ≤80
N48 14.1 13.7 1.41 1.37 ≥10.5 ≥836 ≥11 ≥876 49 45 390 358 ≤80
N50 14.5 14.0 1.45 1.40 ≥10.5 ≥836 ≥11 ≥876 51 47 406 374 ≤60
N52 14.8 14.3 1.48 1.43 ≥10.5 ≥836 ≥11 ≥876 53 49 422 390 ≤60
30M 11.3 10.8 1.13 1.08 ≥10 ≥796 ≥14 ≥1114 31 28 247 223 ≤100
33M 11.8 11.3 1.18 1.13 ≥10.5 ≥836 ≥14 ≥1114 34 31 271 247 ≤100
35M 12.3 11.8 1.23 1.18 ≥10.9 ≥868 ≥14 ≥1114 36 34 287 271 ≤100
38M 12.6 12.3 1.26 1.23 ≥11.3 ≥899 ≥14 ≥1114 39 36 311 287 ≤100
40M 12.9 12.6 1.29 1.26 ≥11.6 ≥923 ≥14 ≥1114 41 38 327 302 ≤100
42M 13.3 12.9 1.33 1.29 ≥12 ≥955 ≥14 ≥1114 43 40 342 318 ≤100
45M 13.7 13.3 1.37 1.33 ≥12.5 ≥995 ≥14 ≥1114 46 43 366 342 ≤100
48M 14.1 13.7 1.41 1.37 ≥12.9 ≥1027 ≥14 ≥1114 49 45 390 358 ≤100
50M 14.5 14.0 1.45 1.40 ≥13 ≥1033 ≥14 ≥1114 51 47 406 374 ≤100
30H 11.3 10.8 1.13 1.08 ≥10 ≥796 ≥17 ≥1353 31 28 247 223 ≤120
33H 11.8 11.3 1.18 1.13 ≥10.5 ≥836 ≥17 ≥1353 34 31 271 247 ≤120
35H 12.3 11.8 1.23 1.18 ≥10.9 ≥868 ≥17 ≥1353 36 33 287 263 ≤120
38H 12.6 12.3 1.26 1.23 ≥11.3 ≥899 ≥17 ≥1353 39 36 311 287 ≤120
40H 12.9 12.6 1.29 1.26 ≥11.6 ≥923 ≥17 ≥1353 41 38 327 302 ≤120
42H 13.3 12.9 1.33 1.29 ≥12 ≥955 ≥17 ≥1353 43 40 342 318 ≤120
45H 13.7 13.3 1.37 1.33 ≥12.3 ≥979 ≥17 ≥1353 46 43 366 342 ≤120

 

Grade Br HcB Hcj (BH )max Max Working Temperature
KGs T KOe KA/m KOe KA/m MGOe KJ/m 3 L/D=0.7
Max Min Max Min Min Min Min Min Max Min Max Min
48H 14.1 13.7 1.41 1.37 ≥12.5 ≥995 ≥17 ≥1353 49 46 390 366 ≤120
30SH 11.4 10.8 1.14 1.08 ≥10.1 ≥804 ≥20 ≥1592 31 28 247 223 ≤150
33SH 11.8 11.4 1.18 1.14 ≥10.6 ≥844 ≥20 ≥1592 34 31 271 247 ≤150
35SH 12.3 11.8 1.23 1.18 ≥11.0 ≥876 ≥20 ≥1592 36 33 287 263 ≤150
38SH 12.6 12.3 1.26 1.23 ≥11.4 ≥907 ≥20 ≥1592 39 36 311 287 ≤150
40SH 12.9 12.6 1.29 1.26 ≥11.6 ≥939 ≥20 ≥1592 41 38 326 302 ≤150
42SH 13.3 12.9 1.33 1.29 ≥12.4 ≥987 ≥20 ≥1592 43 40 342 318 ≤150
45SH 13.7 13.2 1.37 1.32 ≥12.6 ≥1003 ≥20 ≥1592 46 42 366 334 ≤150
28UH 10.8 10.4 1.08 1.04 ≥9.6 ≥764 ≥25 ≥1989 29 26 231 207 ≤180
30UH 11.4 10.8 1.14 1.08 ≥10.1 ≥804 ≥25 ≥1989 31 28 247 223 ≤180
33UH 11.8 11.4 1.18 1.14 ≥10.7 ≥852 ≥25 ≥1989 34 31 271 247 ≤180
35UH 12.3 11.8 1.23 1.18 ≥10.8 ≥860 ≥25 ≥1989 36 33 287 263 ≤180
38UH 12.6 12.3 1.26 1.23 ≥11.3 ≥899 ≥25 ≥1989 39 36 311 287 ≤180
40UH 12.9 12.5 1.29 1.25 ≥11.3 ≥899 ≥25 ≥1989 41 38 326 302 ≤180
42UH 13.3 12.8 1.33 1.28 ≥11.6 ≥923 ≥25 ≥1989 43 40 342 318 ≤180
28EH 10.8 10.4 1.08 1.04 ≥9.8 ≥780 ≥30 ≥2388 29 26 231 207 ≤200
30EH 11.4 10.8 1.14 1.08 ≥10.1 ≥804 ≥30 ≥2388 31 28 247 223 ≤200
33EH 11.8 11.4 1.18 1.14 ≥10.3 ≥820 ≥30 ≥2388 34 31 271 247 ≤200
35EH 12.3 11.7 1.23 1.17 ≥10.5 ≥836 ≥30 ≥2388 36 33 287 263 ≤220
38EH 12.6 12.2 1.26 1.22 ≥11.3 ≥899 ≥30 ≥2388 39 35 311 278 ≤220
28AH 10.9 10.4 1.09 1.04 ≥9.8 ≥780 ≥35 ≥2785 29 33 231 207 ≤230
30AH 11.3 10.8 1.13 1.08 ≥10.1 ≥804 ≥35 ≥2785 31 26 247 223 ≤230
33AH 11.8 11.3 1.18 1.13 ≥10.3 ≥820 ≥33 ≥2625 34 28 271 247 ≤230
35AH 12.3 11.7 1.23 1.17 ≥10.5 ≥860 ≥33 ≥2625 36 33 287 263 ≤230

 

          

Demagnetization curve of grade N40SH                                     Demagnetization curve of grade N42SH 

         

Demagnetization curve of grade N39SH                                     Demagnetization curve of grade N28EH  

        

Demagnetization curve of grade N35UH                                         Demagnetization curve of grade N42H

Special Propertv Data

Grade Item (Lost percent when heat up %/℃)(20℃~1 50℃)(Lost weight standard)mg/cm2
Br Hcj
Normal Grade -(0.1 1 ~0.1 2) -(0.58~0.70) ≤80
"T"Grade1 -(0.095~0.1 1 5) -(0.46~0.59 ≤15
"L"Grade2 " -(0.1 0~0.1 2) -(0.55~0.65) ≤5
"TL"Grade3 -(0.095~0.1 1 5) -(0.46~0.59) ≤5

Remark :
1) “T” grade seris product can be better temperature performance, and it could be used from "H" grade like 45HT、35SHT、38UHT;
2) “L” rade seris product can be better lost weight performance, and our lost weight test standard is 1 21℃ 2atm 95%Humidity,168hours;
3) “TL” rade seris product have both the "L" and "T" grade.

Physical Property

Parameter Unit Reference Value
Vickers hardness Hv ≥550
Density g/cm3 ≥7.40
RecalPenmeability μr1.05
Curie point Tc\℃ 312~380
Specific resistanceμ Ω ·cm 150
Bending strength MPa 250
Compressive strength MPa 1000~1100
Thermal expansion (⊥) ℃-1 -~3)×10-6K
Thermal expansion ( // )℃-1 -~4)×10-6K

NdFeB Curves


Magnetic Properties

Item Inspecting method Inspecting standard
Magnetic performance GB/T 13560-2000 GB/T3217-92
Weightlessness rate Test cases with constant temperature & constant pressure ,96hrs ,(130±2℃(0.27MPa)Normal products :≤50mg/cm2 ; Low weight-loss products :≤10mg/cm2
Density Drainage method for measuring 7.4-7.6g/ cm3
ROHS requirements Equivalent to use the green purchasing standards CS-K1100 (2 edition) in SANYO
Mechanical performance index

Hardness: 570HV Fracture toughness :2.5-5 Mpam2
Resistivity:150μΩ·cm Specific heat:0.502 Kj· (kg·℃
Compressive strength:780 N/mm2 Thermal conductivity :8.9551 w/m·K
Bending strength :290 Mpa Thermal expantion coefficient(in vertical orientation direction):-4.8X10-6K

NdFeB Magnets Magnetization

NdFeB Coating

On the basis of producing high quality raw blocks, Precision Magtech has been researching and developing updated surface protection technology vigorously. We can provide customers with high quality coatings and humidity resistance of coated magnets are quite good to assure magnets safe enough even in rigorous environments.

During the process of coating and plating,  Precision Magtch attaches great importance to environment protection, all coatings meet the requirements of ROHS.

Neo magnets are known for their high temperature resistance, making them durable and functional in temperatures exceeding 200°C. This quality makes them ideal for heavy industry applications. Sintered Neodymium, however, is sensitive to oxidization and can develop corrosion, so magnets are usually coated with Nickel+Copper+Nickel,Nickel+Sn, Zn(galvanization), Epoxy and Passivation for their protection.

Type Thickness Colour Temperature PCT SST Characteristic
Zn 5-10μm Blue Silver ≤160℃>48hr protection for most products
Ni+Sn 10-30μm Semibright Silver ≤160℃>48hr>96hr excellent climate&salt spray resistance
Ni 10-30μm Blue Silver ≤200℃>48hr>96hr excellent climate&salt spray resistance , suitable for clean-room
Al Spraying 6-20μm Dark Silver ≤200℃>288hr superior resistance to salt &humid atmosphere suitable for big size or anomalous magnets
IVD Al 10-30μm Silver White ≤400℃>48hr>288hr superior resistance to salt&humid atmosphere , thickness equality , excellent adhesive attraction
Epoxy 10-30μm Black Gray ≤120℃>48hr>96hr well climate&salt spray resistance


Machining Capacity

Precision Magtech has advanced equipment and strong ability of machining. Good process performance is available for various shapes of complex, precise and big magnets including cubes, segments, disks and rings etc.

A, Dimensions and Shapes

B, Tolerances

1. Cubes

Dimension (mm) Tolerance (mm) Parallelism (mm) Perpendicularity
L≤10±0.03 0.04 0.5 degree for adjacent sides
10<L≤25±0.03 0.06
25<L≤63±0.04 0.10
L>63±0.06 0.12

2. Disks

OD Dimension (mm) Tolerance (mm) Cylindricitym (mm) Circular Run-out (mm)
D≤10±0.02 0.03 0.08
10<D≤25±0.02 0.03 0.08
D>25±0.03 0.04 0.10

3. Segments

Item Dimension (mm) Tolerance (mm)
Thickness T≤10±0.04
10<T≤25±0.05
Length L≤10±0.03
10<T≤25±0.03
25<T≤63±0.04
L>63±0.06
Chordal Length W≤63±0.05
W>63±0.06

4. Ring

ID Dimension (mm) Tolerance (mm) Coaxiality (mm)
d≤3±0.04 0.06
3<d≤6±0.05 0.06
d>6±0.05 0.10


Applications

Packing of NdFEB magnets

According to different shipping way and Customer’s requirements, we make the most convenient and safe way packing for customers.


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