Alnico Magnets For High Heat Applications

Featured Product from Master Magnetics, Inc.

Alnico magnets are made primarily from aluminum, nickel, cobalt, copper, iron and sometimes titanium. They can be either cast or sintered.


Cast Alnico is melted and poured into a mold. Once solidified, the material is rough ground and then heat-treated and cooled, sometimes in a magnetic field. When treated in the presence of a magnetic field, the magnet is called anisotropic. This orients the material to take on maximum magnetization and allows a higher gauss level. A cast magnet that is not heat-treated in a magnetic field is called isotropic. After heat treatment and cooling, the material can be ground to specific tolerances and then magnetized.

Sintered Alnico is made from a powdered mixture of ingredients that are pressed into a die under tons of pressure, sintered in a hydrogen atmosphere and then cooled either within a magnetic field or without (anisotropic vs. isotropic).

Attributes of Cast Alnico

  • Size parameters range from 1 ounce to about 70 pounds
  • Will cast to a variety of shapes and sizes

Attributes of Sintered Alnico

  • Size parameters range from about one ounce of material up to one cubic inch
  • Pressed to close tolerance/minimal grinding to finish
  • Mechanically strongest of alnicos

Attributes of Both Cast and Sintered Alnico

  • Very temperature stable, great for high heat applications
  • Maximum working temperature 975° - 1020° F
  • May be ground to size
  • Does not lend itself to conventional machining (hard and brittle)
  • High residual induction and energy product compared to ceramic material
  • Low coercive force compared to ceramic and rare earth materials (more subject to demagnetization)
  • Most common grades are 5 and 8

Applications of Alnico Magnets 

  • Magnetos
  • Separators
  • Sensors
  • Electron tubes
  • Traveling wave tubes
  • Radar Holding magnets
  • Coin acceptors
  • Clutches and bearings
  • Motors
  • Distributors
  • Relays
  • Controls
  • Generators
  • Receivers
  • Telephones Microphones
  • Bell ringers
  • Guitar pickups
  • Loudspeakers
  • Security systems
  • Cow magnets

Various Shapes

Not sure if alnico is the best material for your application? Click here for an attribute and application comparison for all of the magnetic materials we offer.