AlNiCo is a type of permanent magnet which is made from an alloy of Aluminium, Nickel, Cobalt and Iron. AlNiCo magnets are suitable for Reed Switch applications that require a high service temperature as some grades of AlNiCo magnets can work up to 550C.
Alnico is an acronym referring to a family of iron alloys which in addition to iron are composed primarily of aluminium (Al), nickel (Ni) and cobalt (Co), hence al-ni-co. They also include copper, and sometimes titanium. Alnico alloys are ferromagnetic, with a high coercivity (resistance to loss of magnetism) and are used to make permanent magnets. Before the development of rare-earth magnets in the 1970s, they were the strongest type of permanent magnet. Other trade names for alloys in this family are: Alni, Alcomax, Hycomax, Columax, and Ticonal.
The composition of alnico alloys is typically 8–12% Al, 15–26% Ni, 5–24% Co, up to 6% Cu, up to 1% Ti, and the balance is Fe. The development of alnico began in 1931, when T. Mishima in Japan discovered that an alloy of iron, nickel, and aluminum had a coercivity of
400 oersteds (Oe; 0.07957 kA/m), double that of the best magnet steels of the time.