Master Magnetics, Inc.

Alnico magnets, consisting primarily of aluminum, nickel, cobalt, copper, iron, and sometimes titanium, are highly powerful magnets with diverse applications. These magnets can be manufactured through two methods: casting or sintering.

In the casting process, the Alnico materials are melted and poured into a mold. After solidification, the magnet undergoes rough grinding, followed by heat treatment and cooling. Heat treatment within a magnetic field results in an anisotropic or oriented magnet, maximizing magnetization and achieving higher gauss levels. If the magnet is not heat-treated within a magnetic field, it is referred to as isotropic or non-oriented. After cooling, the Alnico magnet can be ground to specific tolerances and magnetized.

Sintered Alnico magnets, on the other hand, are made by pressing a powdered mixture of the same ingredients into a die using immense pressure. This pressed mixture is then sintered in a hydrogen atmosphere and cooled either within or without a magnetic field. The cooling process determines whether the magnet is anisotropic or isotropic. It is important to note that, unless specifically stated, Alnico magnets meet and often exceed the tolerances set by the International Magnetics Association (IMA).

After machining the magnet to the correct tolerances, the magnetizing process takes place. It is crucial to handle Alnico material with care as it is brittle and can easily chip or break if dropped on a hard surface. Additionally, Alnico magnets have a low resistance to demagnetization, leading to power loss if stored improperly with poles repelling each other. For optimal results, it is recommended to store magnetized Alnico magnets with pieces attracting each other or with a steel keeper.

Alnico's hardness and brittleness make conventional machining challenging. However, Master Magnetics, Inc. offers specialized grinding and cutting services for Alnico material. To make sure you get the best product for your needs, get in touch with Master Magnetics, Inc. if you're not sure if Alnico magnets are appropriate for your application.