The story behind Alnico magnets

Ever since the Stone Age man first observed small pieces of Lodestone get attracted to each other, magnets have held man’s imagination. Magnetism, to the ancient man, was magic, something that he couldn’t explain.

The science behind it was eventually discovered and since then magnets have become integral to working of nearly every electrical or electronic device we use. While the general idea is that magnets should be made of iron, very permanent magnets are Alnico.  Not named after an Italian founder, Alnico actually stands for Aluminium, Nickel and Cobalt, the alloys of which, along with Iron, make up the Alnico magnet.

Alnico magnets are generally stronger than typical Ferrite ones, making them ideal for various applications. Until the discovery of Rare earth magnets, Alnico magnets used to be the strongest type of permanent magnets.

Deep in the core of Alnico magnets

Alnico magnets are the strongest types of permanent magnets, second only to Rare Earth Magnets like Neodymium and Samarium-Cobalt. The strongest factors in the favour of Alnico magnets are their extremely good temperature resilience, high residual induction and strong enough magnetic fields generated.

Primary ways of manufacturing Alnico magnets include casting and sintering. The magnets manufactured using casting can be made into any desired shape and size, horseshoes, etc. Sintered magnet, however not very powerful, give very good mechanical characteristics not found in other magnets.

Alnico give magnetic field strength upto around 0.5 Tesla (Unit of magnetism), much stronger than normal Ferrite magnets. Some types of Alnico magnets are also isotropic, hence could be magnetized in any direction, while others are anisotropic. A great advantage of Alnico magnets is that they are very stable.

And if handled with care, can be safer to use as opposed to Rare-earth magnets which have to be handled very carefully in order to avert mishaps or accidents.

The wide spreading field of Alnico magnets

Due to the properties of Alnico magnets, they are in widespread application around the industry. They are relatively strong, inexpensive and safe. They are widely used in industry as well as consumer goods, anywhere where strong permanent magnets are needed. Some of the common applications of Alnico magnets include:

–          Electric Motors
–          Microphones
–          Loudspeakers/ Speakers
–          Rotating machinery
–          Holding devices
–          Instruments
–          Sensing equipment
–          Travelling wave tubes, etc

While Alnico magnets still have a stronghold in the industry, it is soon being replaced by the higher strength and higher energy rare-earth magnets.