Rare earth permanent magnet materials. The main rare earth cobalt permanent magnet material and NdFeB. The former is an intermetallic compound of a rare earth element cerium, praseodymium, lanthanum, neodymium and cobalt formed up to 150 times the energy product of carbon steel, 3 to 5 times the aluminum-nickel-cobalt permanent magnet materials, ferrite permanent magnet 8 ~ 10 times, low temperature coefficient, magnetic stability, the coercive force of up to 800 kA / m. Mainly for low-speed torque motor, start the motor, sensor, magnetic thrust bearing magnetic system. NdFeB is the third generation of rare earth permanent magnet materials, its remanence, coercivity and the maximum energy product higher than the former, non-friable, have good mechanical properties, low alloy density, magnetic components in favor of light , thin, small and ultra-miniaturization. But its magnetic temperature coefficient is high, limiting its application. Composite permanent magnetic material comprises permanent magnetic material powder and a binder of plastic material composite. Since it contains a certain proportion of the binder, so the magnetic properties are significantly lower than the corresponding magnetic material without binder. In addition to the permanent metal composite material, other composite magnetic materials due to the limited heat resistance of the adhesive, low temperature, generally no more than 150 ℃. But the composite magnetic materials high dimensional accuracy, good mechanical properties, the magnet of all parts of uniformity, susceptible to magnets radially oriented and multi-polar magnetic charge. Mainly for the manufacture instrumentation, communications equipment, rotating machinery, magnetic equipment and sports goods.