What are Rare Earth Permanent Magnets (REPMs)?
Rare earth permanent magnets (REPMs) are permanent magnets which are based on some rare earth elements (Sm, Nd, Pr, Dy, Ce, etc.) to form critical magnetic structures. In regard to crystal structures, REPMs include
a. 1:5 type SmCo magnets (hexagonal CaCu5 type structure) also called 1st generation REPMs,
b. 2:17 type SmCo magnets (rhombohedral Th2Zn17 type structure) also called 2nd generation REPMs and
c. Nd2Fe14B magnets (tetragonal crystal structure) also called 3rd generation REPMs.
Compared with other types of permanent magnets such as ceramic/ferrite magnets and AlNiCo magnets, REPMs have much higher maximum energy product and coercivity which allow them to be applied in more high performance and/or more miniaturized motors, devices, instruments and equipments.
The REPMs are widely used in various fields of industrial automation, automobile, consumer electronics, computer, household appliances, telecommunications, energy, medical, aerospace, defense, etc.