Permanent-magnet material of permanent magnet synchronous motor used in the following ways:
First. Al-NI-co. It is an alloy of iron and nickel, aluminum and cobalt. Its advantages are large Br, magnetic high, stable, less expensive, the disadvantage is that Hc is unlikely, weak ability to resist demagnetization, hard and brittle materials.
Second. Ferrite. It is iron and strontium, barium and one or more elements of composite compounds. Its advantage is that Hc large, strong resistance to demagnetization, cheap, the proportion of small, job stability is not needed, the disadvantage is that Br is not, influence of temperature on magnetic properties of larger, unsuitable for large temperature changes.
Third. Rare-earth cobalt. The advantage of a good comprehensive performance, have a strong ability to resist demagnetization, magnetic temperature stability, allows high working temperatures (200~250 ° c) and disadvantage is more expensive. Rotor for permanent magnet synchronous motors are mainly used at present is the rare-earth cobalt.
IV. Neodymium-iron-boron. The advantage is a good comprehensive performance, cheap disadvantage is to allow lower working temperature (120 ° c), because it contains more iron, neodymium, so prone to rust.