What Is An Alnico Magnet & What Is It Used For?

Written By: msilvestro Category: Magnets Date: 2017-06-01 Hits: 1581

What Is An Alnico Magnet and What Is It Used For?

Alnico was the strongest permanent magnet available until rare earth magnets were developed. Learn more about these magnets, how they’re made, and what they’re used for here.

Before the development of rare earth magnets, alnico magnets ruled the magnet world.

While they are overshadowed and have largely been replaced by stronger rare earth magnets, alnico magnets are still commonly used in various industries for specific jobs such as high temperature handling equipment and manufacturing of sensors, to name a few.

What Is Alnico?

Excellent temperature stability, high residual induction, and relatively high energies.

Alnico is a combination of Al (aluminium), Ni (nickel), and Co (cobalt).

This development and introduction of Alnico meant that expensive electromagnets could be replaced with permanent magnets in essential devices like motors and generators.

Alnico magnets are permanent magnets that are primarily made of aluminium, nickel and cobalt.

How Is Alnico Made?

Alnico magnets are manufactured through either casting or sintering processes.

  • Cast magnets are manufactured by pouring a molten metal alloy into a mold and then further processing it through various heat cycles. The end product is a magnet with a dark gray exterior with a rough surface, but machined magnet surfaces have a shiny appearance.
  • Sintered magnets are manufactured by compacting fine alnico powder in a press, and then sintering the compacted powder into a solid magnet.

Where Are Alnico Magnets Used?

Despite being overshadowed and largely replaced by rare earth magnets, Alnico still perform better than their successors in specific situations and therefore are still used for many applications which require high operating temperatures.

Alnico magnets are most commonly used in the following:

  • Electric motors
  • Microphones
  • Engineering applications
  • Aerospace applications
  • Military applications
  • Sensors
  • Bearings
  • And more!

 

The Strength of Alnico Magnets

Alnico has a high magnetic strength and a low resistance to being demagnetized and re-magnetized.

Before the development of rare earth magnets, alnico magnets were the strongest type of magnet available.

Today, alnico magnets have been largely replaced by stronger rare earth magnets, such as neodymium.

Alnico Vs. Ferrite

  • Alnico magnets are generally stronger than regular ferrite (ceramic) magnets
  • Alnico magnets are electrically conductive, unlike ceramic/ferrite magnets
  • They are less brittle than most rare earth magnets
  • Produce a strong magnetic field
  • Alnico magnets are able to operate at the highest temperatures of any magnetic material and keep their magnetism even when red hot

Pros & Cons of Alnico Magnets

Pros

Cons

Excellent temperature stability up to 1,000F

Can be more easily demagnetized than other magnetic materials

-High residual induction

-Are relatively costly, as they contain both nickel and cobalt

-Does not corrode

-Cast alnico magnets often have casting pores and voids, which can be problematic for appearance and magnetic flux

-Cast alnico magnets can be produced in relatively complex shapes

 

 

Learn More

Want to learn more about these incredible magnets?

Jobmaster Magnets stocks a wide variety of alnico magnets in a range of different shapes and sizes, and can custom manufacture any alnico magnet to suit all of your needs.

Contact us today to learn more!

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