Neodymium Magnet Information

Rare Earth

Neodymium magnets are a member of the Rare Earth magnet family and are the most powerful permanent magnets in the world. They are also referred to as NdFeB magnets, or NIB, because they are composed mainly of Neodymium (Nd), Iron (Fe) and Boron (B). They are a relatively new invention and have only recently become affordable for everyday use.
Neodymium Iron Boron (NdFeB) magnet has high remanence, high coercive force, high energy product and high performance/cost ratio. It is easily formed into various sizes, widely used in motor, sensor, meter, sound device, magnetic separator, automobile, aviation, aerospace and other applications. It is prone to corrosion in humid environments, so it usually needs surface treatment according to customers’ requirements. The coatings we can offer include: nickel, zinc, gold, silver, epoxy and parylene.

PRODUCTION PROCESS FLOWCHART

Grades of Neodymium (MAGNETIC PROPERTIES)

N35, N38, N42, N38SH…what does it all mean? Neodymium magnets are all graded by the material they are made of. As a very general rule, the higher the grade (the number following the ‘N’), the stronger the magnet. The highest grade of neodymium magnet currently available is N52. Any letter following the grade refers to the temperature rating of the magnet. If there are no letters following the grade, then the magnet is standard temperature neodymium. The temperature ratings are standard (no designation) – M – H – SH – UH – EH.

Grade Br Hcb Hcj (BH)max Working Temp
mT Gs kA/m Oe kA/m Oe kJ/m3 MGOe ℃
N35 1180-1230 11800-12300 ≥868 ≥10900 ≥955 ≥12000 263-287 33-36 ≤80
N38 1220-1280 12200-12800 ≥899 ≥11300 ≥955 ≥12000 287-310 36-39
N40 1260-1310 12600-13100 ≥923 ≥11600 ≥955 ≥12000 302-326 38-41
N42 1280-1340 12800-13400 ≥923 ≥11600 ≥955 ≥12000 318-342 40-43
N45 1320-1370 13200-13700 ≥876 ≥11000 ≥955 ≥12000 342-366 43-46
N48 1360-1420 13600-14200 ≥836 ≥10500 ≥876 ≥11000 358-390 45-48
N50 1390-1450 13900-14500 ≥836 ≥10500 ≥876 ≥11000 374-406 47-51
N52 1420-1480 14200-14800 ≥796 ≥10000 ≥876 ≥11000 390-422 49-53
N35M 1180-1230 11800-12300 ≥868 ≥10900 ≥1114 ≥14000 263-287 33-36 ≤100
N38M 1220-1280 12200-12800 ≥899 ≥11300 ≥1114 ≥14000 287-310 36-39
N40M 1260-1310 12600-13100 ≥923 ≥11600 ≥1114 ≥14000 302-326 38-41
N42M 1280-1340 12800-13400 ≥923 ≥11600 ≥1114 ≥14000 318-342 40-43
N45M 1340-1390 13400-13900 ≥876 ≥11000 ≥1114 ≥14000 342-366 43-46
N48M 1360-1420 13600-14200 ≥876 ≥11000 ≥1114 ≥14000 366-390 46-49
N35H 1180-1230 11800-12300 ≥868 ≥10900 ≥1353 ≥17000 263-287 33-36 ≤120
N38H 1220-1280 12200-12800 ≥899 ≥11300 ≥1353 ≥17000 287-310 36-39
N40H 1260-1310 12600-13100 ≥923 ≥11600 ≥1353 ≥17000 302-326 38-41
N42H 1280-1340 12800-13400 ≥923 ≥11600 ≥1353 ≥17000 318-342 40-43
N45H 1330-1390 13300-13900 ≥923 ≥11600 ≥1353 ≥17000 342-366 43-46
N48H 1360-1420 13600-14200 ≥923 ≥11600 ≥1274 ≥16000 366-390 46-49
N33SH 1140-1190 11400-11900 ≥836 ≥10500 ≥1592 ≥20000 247-270 31-34 ≤150
N35SH 1180-1230 11800-12300 ≥868 ≥10900 ≥1592 ≥20000 263-287 33-36
N38SH 1220-1280 12200-12800 ≥899 ≥11300 ≥1592 ≥20000 287-310 36-39
N40SH 1260-1310 12600-13100 ≥923 ≥11600 ≥1592 ≥20000 302-326 38-41
N42SH 1280-1340 12800-13400 ≥923 ≥11600 ≥1592 ≥20000 318-342 40-43
N45SH 1330-1390 13300-13900 ≥923 ≥11600 ≥1592 ≥20000 342-366 43-46
N28UH 1030-1090 10300-10900 ≥780 ≥9800 ≥1990 ≥25000 207-231 26-29 ≤180
N30UH 1090-1140 10900-11400 ≥812 ≥10200 ≥1990 ≥25000 223-247 28-31
N33UH 1130-1170 11300-11700 ≥852 ≥10700 ≥1990 ≥25000 247-263 31-33
N35UH 1180-1220 11800-12200 ≥868 ≥10900 ≥1990 ≥25000 263-287 33-36
N38UH 1220-1270 12200-12700 ≥899 ≥11300 ≥1990 ≥25000 287-310 36-39
N28EH 1030-1090 10300-10900 ≥780 ≥9800 ≥2388 ≥30000 207-231 26-29 ≤200
N30EH 1080-1130 10800-11300 ≥812 ≥10200 ≥2388 ≥30000 223-247 28-31
N33EH 1130-1170 11300-11700 ≥852 ≥10700 ≥2388 ≥30000 247-263 31-33
N35EH 1180-1220 11800-12200 ≥868 ≥10900 ≥2388 ≥30000 263-287 33-36

Platings/Coatings

Neodymium magnets are a composition of mostly Neodymium, Iron and Boron. If left exposed to the elements, the iron in the magnet will rust. To protect the magnet from corrosion and to strengthen the brittle magnet material, it is usually preferable for the magnet to be coated. There are a variety of options for coatings, but nickel is the most common and usually preferred. Our nickel plated magnets are actually triple plated with layers of nickel, copper, and nickel again. This triple coating makes our magnets much more durable than the more common single nickel plated magnets. Some other options for coating are zinc, tin, copper, epoxy, silver and gold. Our gold plated magnets are actually quadruple plated with nickel, copper, nickel and a top coating of gold.

Pctures
Coating Zinc Nickel Gold Silver Epoxy Parylene
Thickness 7-15um 15-21um 16-23um 16-23um 20-38um 10-15um
Salt spray test 12 hours 24 hours 36 hours 24 hours 48 hours 48 hours

Machining

Neodymium material is brittle and prone to chipping and cracking, so it does not machine well by conventional methods. Machining the magnets will generate heat, which if not carefully controlled, can demagnetize the magnet or even ignite the material which is toxic when burned. It is recommended that magnets not be machined.

SIZE RANGE

Shaps Outer Diameter/Length Inner diameter/Width Thickness
Maximum 220.00mm 50.00mm
Minimum 0.30mm 0.50mm
Maximum 100.00mm 150.00mm 50.00mm
Minimum 0.5mm 0.50mm 0.50mm
Maximum 220.00mm 80.00mm 50.00mm
Minimum 1.00mm 0.60mm 0.50mm
Segment, Arc and other irregular shapes can be made according to customer’s samples or drawing.

PHYSICAL AND MANUFACTURING CHARACTERISTICS

Curie Temperature (°C) 310-370
Maximum Operating Temperature (°C) 80-240
Resistivity (µ ohm.cm) 160
Hardness (Hv) 560-580
Density (g/cm3) 7.40
Relative Recoil Permeability (µrec) 1.05
Saturation Field Strength, kOe (kA/m) 30-40 (2400-3200)
Temperature Coefficient of Br (%/°C) -0.12 ~ -0.10
Temperature Coefficient of iHc (%/°C) -0.6

Strength

If you’ve never handled neodymium magnets before, you will be amazed at their strength. Neodymium magnets are over 10x stronger than the strongest ceramic magnets. If you are currently using ceramic magnets in your project, you could probably use a much smaller neodymium magnet and have greater holding force.

APPLICATION

Electrical machinePermanent magnet meterElectronics IndustryAutomobile IndustryPetroleum Chemical IndustryMedical MRISound equipmentMagnetic suspension systemMagnetic actuating MechanismMagnetotherapy facilities etc.

The potential uses for strong neodymium magnets are unlimited!