Alnico

[2] 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 rest 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 (32 kA/m), double that of the best magnet steels of the time.

Anisotropic alloys generally have greater magnetic capacity in a preferred orientation than isotropic types.

Alnico's remanence (Br) may exceed 12,000 G (1.2 T), its coercivity (Hc) can be up to 1000 oersteds (80 kA/m), its maximum energy product ((BH)max) can be up to 5.5 MG·Oe (44 T·kA/m).

[5] This property, as well as its brittleness and high melting point, results from the strong tendency toward order due to intermetallic bonding between aluminum and other constituents.

)[8] These classification numbers, while still in use, have been deprecated in favor of a new system by the MMPA, which designates Alnico magnets based on maximum energy product in megagauss-oersteds and intrinsic coercive force as kilo oersted, as well as an IEC classification system.

While sintering can also produce a range of shapes, it may not be as suitable for extremely intricate or detailed designs compared to casting.

[10][13] Most alnico produced is anisotropic, meaning that the magnetic direction of the grains is randomly oriented when initially made.

Both isotropic and anisotropic alnico require proper heat treatment to develop optimal magnetic properties.