Alnico is an alloy material composed of aluminum, nickel, cobalt, iron and other trace metal elements. It has the characteristics of corrosion resistance and high temperature resistance, but it has low mechanical strength, high hardness, brittleness and poor machinability. .

The intrinsic coercive force of AlNiCo is very low, usually less than 160 kA/m, the demagnetization curve changes nonlinearly, and the recovery line does not coincide with the demagnetization curve, so special attention should be paid to its particularity when designing the magnetic circuit. The magnet is subjected to magnetic stabilization treatment. According to its low coercive force, it is strictly forbidden to contact with any ferromagnetic objects during use, so as not to cause local irreversible demagnetization or distortion of magnetic flux density distribution. In order to enhance its ability to resist demagnetization, the pole faces of AlNiCo permanent magnets are often designed as long cylinders or rods.