Neodymium magnets (NdFeB)

Short description

Neodymium-Ferro-Boron (NdFeB) magnets are delivered by Goudsmit under the brand name Neoflux®. It is the most powerful magnet, with a very high energy product.

Characteristics

  • Energy product above 52 MGOe possible
  • Very powerful magnets
  • Lower resistance to corrosion
  • Application: i.a. automotive, sensors, speakers, scanners
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Neodymium magnets (NdFeB)

Detailed product description

Goudsmit supplies Neodymium-Iron-Boron magnet under the brand name Neoflux®.

Neodymium Iron Boron (NdFeB), also described as a ‘rare earth magnet’ is the strongest and most powerful commercially available magnet material, with energy products of up to 52 MGOe. Since its discovery in the early 1980’s, processes are constantly improving in relation to the performance of NdFeB, meaning that any data surrounding it can quickly go out of date.
Having undergone numerous enhancements, today this material is the most popular and widely used magnet alloy. It doesn’t perform well environmentally however, with issues such as poor thermal performance, mechanical brittleness, and the fact that it’s prone to corrosion, limiting its use in some applications.
Despite this, NdFeB offers the highest available magnetic energy density with BHMax values ranging from 33 to 52 MGOe.  This physical property alone allows designers to use relatively small amounts of magnetic alloy when compared to other magnetic materials – explaining its widespread popularity in the world of engineering components.

 

APPLICATIONS

of Neodymium Iron Boron (NdFeB)
With its high power and performance, Neodymium is used in a variety of applications such as:
• Wind turbines
• Hard disk drive motors
• Electric vehicles
• Loudspeakers
• Cars
• MRI Scanners
• Magnetic Separators


KEY BENEFITS


There are a lot of benefits associated with this magnetic material, including:
• Very high strength performance.
• NdFeB delivers considerably more energy per cubic metre that any other magnetic material currently available.
• Relatively low cost. For example, by weight, about 20x that of Ferrite magnets, and by "Dollar per BHmax" about 1.5x that of ferrite magnets.
• It’s relatively easy to machine, especially when compared to Samarium Cobalt and Alnico magnets.

What are some of the key challenges with Neodymium-Iron-Boron?
It’s difficult to find the perfect material, and as such, NdFeB comes with some drawbacks:
• Properties can deteriorate rapidly, especially at temperatures above 150°C. The deterioration all depends on the
  grade and permeance coefficient at which the magnet operates at.
• Since NdFeB magnets are prone to corrosion, most grades of the magnets will require protected against
  oxidation, either by coating or plating the magnets.

TECHNICAL DETAILS


Here are a few facts of NdFeB:
• Its density is 0.275 lbs. per cubic inch.
• The magnetising field required for saturation is about 35kOe.
• Available grades of Neo range from about 3330 to 5311, where the first 2 digits represent BHmax; and the second
   two digits represent intrinsic coercivity (Hci).
 

MANUFACTURING METHODS

for Neodymium-Iron-Boron magnets
There are various manufacturing processes available for NdFeB magnets:
• Sintering is the most common process carried out. It involves forming a solid mass of magnetic material through
   compacting with pressure and heat.   
• Bonded Magnets’ are increasingly important magnetic materials. They’re formed by combining magnetic powder
   with a polymer. Their manufacturing processes include:
• Injection Moulding can form bonded magnetic material into complex shapes, and can be moulded directly onto
  other parts to form magnetic assemblies.
• Compression Bonding results in stronger magnetic performance when compared to injection moulding, however,
  only simpler geometries can be formed.
• Calendaring allows the bonded magnet material to be made into flexible magnetic sheets and rolls.

MACHINING NdFeB MAGNETS


• Some machining operations for NdFeB materials can be performed using carbide tools, although surface finishes
  may be less than optimal. In general, NdFeB magnets need to be machined using diamond-grinding techniques.
• Bonded NdFeB is more easily machined. Coolants must be used while machining this material to avoid
  spontaneous combustion of the powder. Machining however, removes a layer of protective coating and therefore
  re-coating for corrosion resistance will be necessary.
• At Goudsmit we are fully equipped to machine these materials to your design specifications.

SURFACE TREATMENTS FOR NdFeB


Due to the poor corrosion resistance of Neodymium, it’s recommended that all surfaces are treated, depending on your application. Here are some things to consider when designing a product containing NdFeB magnets:
• Recently, certain grades of Neo have been produced that exhibit higher resistance to oxidation. For most grades
  however, painting, coating, or plating is generally recommended for NdFeB.
• Plating NdFeB can be a difficult process. It’s unlikely that plating companies without the specialist knowledge of
   plating Neo will be able to achieve good adhesion on Neo magnets.
• Nickel, nickel-copper-nickel, zinc, tin, aluminium, Teflon or epoxy can provide good corrosion resistance for NdFeB
  magnets, though longer lead times or higher volumes may be required. Ion vacuum deposition (IVD) techniques
  can also be used for plating Neo magnets. The IVD plating process is very controllable when it comes to thickness,
  and it has excellent adhesion to the material.
• A variety of organic coatings have been developed for NdFeB which exhibit good corrosion resistance
  characteristics. In harsher environments, it may be advisable to use a combination of coating techniques, or to
  encapsulate the material in a sealed housing.

PRECAUTIONS

when working with Neodymium Iron Boron (NdFeB):
• NdFeB powder is very fine. When it’s dry, it can ignite spontaneously. Therefore, it’s important for your safety, to
  take extra care and precautions when handling NdFeB powder.
• NdFeB magnets can be extremely powerful, and special care needs to be taken when handling these magnets to
  avoid injuries.

PRODUCT DESIGN

Applications for neodymium magnets are diverse & wide ranging. Aerospace engineers have found its outstanding performance invaluable. Its power to weight ratio has made applications previously thought to be impossible, achievable, thus changing design concepts for the modern engineer.
Goudsmit supplies Neodymium magnets and magnetic assemblies to suit your requirements.

 

Neodymium (NdFeB) permanent magnets - table

Grade

Corrosion

stable

Remanence Normal
coercivity
Intrinsic
coercivity
Maximum
energy product
Max.
operating
Temp.
   

Br
mT

Hcb
kA/m
Hcj
kA/m
BH(max)
kJ/m3
 
  specify as min typ min typ min min typ °C
GSN-35   1170 1120 870 920 955 263 279 80
GSN-38   1220 1260 870 920 955 279 303 80
GSN-40   1260 1300 870 920 955 303 318 80
GSN-42   1300 1330 870 920 955 318 334 80
GSN-45   1330 1370 900 930 955 334 358 80
GSN-48   1370 1410 900 930 875 358 382 80
GSN-50   1410 1440 830 850 875 382 398 80
GSN-52   1430 1480 820 840 875 398 422 80
GSN-33M   1140 1170 830 859 1114 239 263 100
GSN-35M   1170 1220 870 891 1114 263 279 100
GSN-38M   1220 1260 900 915 1114 279 303 100
GSN-40M   1260 1300 930 915 1114 303 318 100
GSN-42M   1300 1330 950 915 1114 318 334 100
GSN-45M   1330 1370 980 915 1114 334 358 100
GSN-48M   1370 1410 1010 980 1114 358 382 90
GSN-50M   1410 1440 1030 980 1114 382 398 90
GSN-30H   1080 1140 810 810 1353 223 239 120
GSN-33H   1140 1170 830 830 1353 239 263 120
GSN-35H   1170 1220 870 870 1353 263 279 120
GSN-38H 38H/S 1220 1260 900 900 1353 279 303 120
GSN-40H 40H/S 1260 1300 930 930 1353 303 318 120
GSN-42H 42H/S 1300 1330 950 950 1353 318 334 120
GSN-44H 44H/S 1330 1360 970 970 1353 334 350 120
GSN-46H 46H/S 1360 1380 980 980 1353 350 366 120
GSN-48H 48H/S 1380 1410 1010 1060 1353 366 382 120
GSN-30SH   1080 1140 810 860 1592 223 239 150
GSN-33SH   1140 1170 830 880 1592 239 263 150
GSN-35SH 35SH/S 1170 1220 870 920 1592 263 279 150
GSN-38SH 38SH/S 1220 1260 900 950 1592 279 303 150
GSN-40SH 40SH/S 1260 1300 930 980 1592 303 318 150
GSN-42SH 42SH/S 1300 1330 950 1000 1592 318 334 150
GSN-44SH 44SH/S 1330 1360 970 1020 1592 334 350 150
GSN-28UH 1040 1080 770 810 1989 199 223 180
GSN-30UH 30UH/S 1080 1140 810 860 1989 223 239 180
GSN-33UH 33UH/S 1140 1170 830 880 1989 239 263 180
GSN-35UH 35UH/S 1170 1220  870 920 1989 263 279 180
GSN-38UH 38UH/S 1220 1260 900 950 1989 279 303 180
GSN-40UH 40UH/S 1250 1280 900 950 1989 302 326 180
GSN-28EH   1040 1080 770 810 2387 199 223 200
GSN-30EH 30EH/S 1080 1140 810 860 2387 223 239 200
GSN-33EH 33EH/S 1140 1170 830 880 2387 239 263 200
GSN-35EH 35EH/S 1170 1220 870 920 2387 263 279 200
GSN-38EH 38EH/S 1220 1260 900 950 2387 279 303 200
GSN-25AH 25AH/S 970 1020 730 770 2787 180 200 220
GSN-28AH 28AH/S 1040 1080 770 810 2787 203 218 220
GSN-30AH 30AH/S 1080 1140 810 860 2787 220 250 220
GSN-25BH 25BH/S 950 1000 710 750 3000 170 190 230