Rare-earth magnet
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A rare-earth magnet is a strong permanent magnet made from alloys of rare-earth elements. Developed in the 1970s and 1980s, rare-earth magnets are the strongest type of permanent magnets made, produci
Ferrofluid on glass, with a rare-earth magnet underneath
Neodymium magnet with nickel plating mostly removed
Neodymium magnet balls
Two objects made of neodymium magnets. The right object has the close-packing of equal spheres.
Alnico
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Alnico is a family of iron alloys which, in addition to iron, are composed primarily of aluminium, nickel, and cobalt, hence the acronym al-ni-co. They also include copper, and sometimes titanium. Aln
A "horseshoe magnet" made of Alnico 5, about 1 inch high. The metal bar (bottom) is a keeper, which is placed across the poles when the magnet is not in use. This helps to preserve the magnetization.
Alnico 5 magnet used in a magnetron tube in an early microwave oven. About 3 in (8 cm) long.
Advertisement by Jensen Radio Manufacturing Co. for Alnico 5 loudspeakers in 1945. As illustrated, Alnico 5 allowed a dramatic reduction in size and weight of magnet needed to produce a given flux, from 90 oz in 1930 to 4.6 oz.
Assortment of alnico magnets in 1956. Alnico 5, developed during World War 2, led to a new generation of compact permanent magnet motors and loudspeakers.