What Makes Strong Magnets?

A magnet’s strength is based on its structure and how it is magnetized. Strong magnets include ferrite, alnico, neodymium, and samarium-cobalt magnets. Ferrite and Alnico magnets are made from naturally magnetized minerals. Both of these magnets were the strongest magnets until the invention of rare earth magnets, neodymium and samarium magnets.


Ferrite magnets are made from hematite and magnetite. Magnetite is the strongest naturally occurring mineral in the world. These magnets are ceramic and the methods used to create them are pressing and sintering or injection molding. Ferrites are the least expensive magnets and are probably the first magnets the average child sees.

Most of the minerals in alnico magnets are aluminum, cobalt, and nickel. Alnico magnets are manufactured using casting or sintering. Casting involves pouring the molten metal alloy into a mold and sintering compacts the mineral powder into a solid magnet. Alnico magnets were the strongest permanent magnets available before rare earth magnets and like rare earth magnets are artificially magnetized.

Neodymium magnets were invented by General Motors and Sumitomo Special Metals. The prominent minerals in neodymium magnets are neodymium, iron, and boron. Neodymium is called a rare earth magnet because it is made from rare earth elements that are dispersed and rarely found in concentrated and economically exploitable forms. Rare earth magnets are artificially magnetized when manufactured.

Samarium-cobalt magnets were the first rare earth magnets invented. As the name implies, its elements are samarium and cobalt. While samarium is not as strong as neodymium, both rare earth magnets are the strongest in the world. Whether the magnet of your choice is ferrite, alnico, or a rare earth magnet, these magnets have provided the world with products ranging from hard drives, speakers, electric engines, cordless tools, building blocks for children, and magnetic closures for necklaces.

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