抄録
Recently, the application of Nd-Fe-B sintered magnets on automobile is getting increased. These magnets are applied for driving motors/generators of Hybrid Electric Vehicle and Electric Power Steering motors. However a few improvements of these magnets are required for use of automobile. One point is the improvement on irreversible flux loss at high temperature. Therefore, it is necessary to improve the intrinsic coercivity for application on automobile. Intrinsic coercivity of Nd-Fe-B sintered magnets are depended on anisotropy field of the main phase and metallographical structure. While heavy Rare Earth substitution or some additions increase anisotropy field, other additions such as V or Mo improve factors related with their structure. As a result, the intrinsic coercivity increases. On the other hand, remanence decreases largely by use of these techniques. Therefore, it is important to improve the techniques of increasing remanence are developed simultaneously. In the future, electrical automobile will become major. So we must continue R&D for Nd-Fe-B sintered magnets to be the most important material in it.
