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.
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
Alnico
…They also include copper, and sometimes titanium. Alnico alloys are ferromagnetic, and are used to make permanent magnets. Before the development of rare-earth magnets in the 1970s, they were the strongest permanent magnet type. Other trade names for alloys in this family are: Alni, Alcomax, Hycomax, Columax, and…
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.