NEODYMIUM

MAGNETS

NEODYMIUM

MAGNETS

3D Unleashed currently sells Neodymium magnets into the industry for use in manufacturing operations, Toys, Accessories, Door Closing mechanisms, Point of display, jewelry to name a few applications, but the application potentials are vast. 

  • Disk Magnets
  • Ring Magnets
  • Rectangular (Block) Magnets
  • Ball Magnets
  • Custom dimensions
3d unleashed magnet

 

 

The Neodymium magnet (also known as NdFeB, NIB or Neo magnet), the most widely used type of rare-earth magnet, is a permanent magnet made from an alloy of rare-earth elements : Neodymium (Nd), Iron (Fe) and Boron (B) to form the Nd2Fe14B tetragonal crystalline structure.

TECH TALK:

Developed in the 1980’s, neodymium magnets are the strongest type of permanent magnet commercially available. There are two principal neodymium magnet manufacturing methods:

  • Classical powder metallurgy or sintered magnet process
  • Rapid solidification or bonded magnet process

Sintered Nd-magnets are prepared by the raw materials being melted in a furnace, cast into a mold and cooled to form ingots. The ingots are pulverized and milled; the powder is then sintered into dense blocks. The blocks are then heat-treated, cut to shape, surface treated and magnetized.

Bonded Nd-magnets are prepared by melt spinning a thin ribbon of the NdFeB alloy. The ribbon contains randomly oriented Nd2Fe14B nano-scale grains. This ribbon is then pulverized into particles, mixed with a polymer, and either compression moulded or injection-moulded into bonded magnets. Bonded magnets offer less flux intensity than sintered magnets, but can be net-shape formed into intricately shaped parts.

MAGNETIC PROPERTIES:

The magnetic energy product BHmax of neodymium magnets is about 18 times greater than “ordinary” magnets by volume. This allows rare earth magnets to be smaller than other magnets with the same field strength.

Some important properties used to compare permanent magnets are:

  • Remanence (Br) which measures the strength of the magnetic field
  • Coercivity (Hci) the material’s resistance to becoming demagnetized
  • Energy product (BHmax) the density of magnetic energy
  • Curie temperature (TC) the temperature at which the material loses its magnetism

Neodymium magnets have higher remanence, much higher coercivity and energy product, but often lower Curie temperature than other types of magnets.

 

CORROSION:

Rare Earth magnets are extremely brittle and also vulnerable to corrosion, so they are usually plated or coated to protect them from breaking, chipping, or crumbling into powder.

The most popular protective surface treatment used is nickel plating, but other coatings such as gold, zinc, and tin plating and epoxy-resin coating can also provide corrosion protection.

 

MAGNETIC GRADING:

Neodymium magnets are graded according to their maximum energy product, which relates to the magnetic flux output per unit volume. Higher values indicate stronger magnets and range from N35 up to 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 (80°C). The temperature ratings are standard (no designation) – M (100°C) – H (120°C) – SH (150°C) – UH (180°C) – EH (200°C). 

Grades of Neodymium magnets:

  • N35-N52
  • N33M-N48M
  • N30H-N45H
  • N30SH-N42SH
  • N30UH-N35UH
  • N28EH-N35EH

COMMON APPLICATIONS FOR
NEODYMIUM MAGNETS:

Neodymium magnets have replaced alnico and ferrite magnets in many applications in modern technology where strong, magnetically stable permanent magnets are required.  

A major advantage of the Neodymium magnet is that greater strength per volume allows the use of smaller, lighter magnets for a given application. The manufacturing process is in addition dimensionally accurate to tolerance of ±0.1mm and it allows for small custom, cost effective production runs, in specified shape, magnetic strength and temperature stability.

3D Unleashed currently sells Neodymium magnets into the industry for use in manufacturing operations, Toys, Accessories, Door Closing mechanisms, Point of display, jewelry, but the application potentials are vast. 

Standard Magnet Options:

  • N35 & N38 Neodymium Disk Magnets
  • N35 Neodymium Ring Magnets
  • N35 Neodymium Rectangular (Block) Magnets
  • N35 Neodymium Ball Magnets
  • N35 Neodymium Custom dimensions

Standard Coating Options:

  • Uncoated
  • Nickle Plated
  • Zinc Plated

CAUTION! HAZARDS!

The greater forces exerted by rare-earth magnets create hazards that may not occur with other types of magnet. Neodymium magnets larger than a few cubic centimeters are strong enough to cause injuries to body parts pinched between two magnets, or a magnet and a ferrous metal surface, even causing broken bones.

Magnets that get too near each other can strike each other with enough force to chip and shatter the brittle material, and the flying chips can cause various injuries, especially eye injuries. There have even been cases where young children who have swallowed several magnets have had sections of the digestive tract pinched between two magnets, causing injury or death. The stronger magnetic fields can be hazardous to mechanical and electronic devices, as they can erase magnetic media such as floppy disks and credit cards, and magnetize watches.