These magnets are based mainly on iron (Fe), aluminum (Al), nickel (Ni) and cobalt (Co). The magnets are fragile and not ductile. Therefore, after the raw metal is melted at high temperature and turned into an alloy, it is cast into a casting mold. These magnets are therefore also known as cast magnets.
Al-Ni-Co magnets achieve high Br values and high temperature stability, readily cause low-temperature demagnetization and thermal demagnetization, achieve high mechanical strength, and offer other advantages. However, these magnets have low magnetic coercive force (Hcj) and readily undergo demagnetization due to an external magnetic field, are unsuited for thin products, and placed under other constraints. In the design process, it is therefore important to select a method of magnetization that allows for sufficient shape and magnetic characteristics, and a method of assembly in which consideration is given to demagnetization.