Made of powder metallurgy legal oxide magnet, columns, column and strontium barium oxygen system oxygen system compared with other magnets, with a small specific gravity, rotor inertia small & lsquo; Remanence low density and high jiao coercivity, not susceptible to the influence of magnetic field, the cheapest permanent magnets, suitable for all kinds of motor, according to the manufacturing methods, using sintered ferrite and epoxy resin as adhesive of die-casting ferrite, sintered ferrite & rsquo; Magnetic energy is higher, but difficult to make complex shape of magnetic pole, die-casting ferrite with injection molding and die casting forming two methods, the former can form all kinds of complicated shape, but magnetic slightly worse than the latter.