High performance NdFeB magnets

Although the production and applications of NdFeB magnets have increased enormously in the last decade because of their outstanding magnetic properties at room temperature, some applications were limited because of poor thermal stability and corrosion resistance. To address these problems, there have been many efforts and much progress. In many instances, the alloy modifications produced an improvement of some characteristics but only at the expense of other characteristics. It is therefore necessary to find a method (or alloy) for improving the thermal stability, coercivity, and corrosion resistance without sacrificing performance. We have found that the proper control of very small amounts of Cu, Co, and O in (Nd, Dy)FeB alloys substantially improves the coercivity, high-temperature capabilities, and corrosion resistance without a reduction of remanence. As a result, a high performance NdFeB magnet with excellent temperature stability and corrosion resistance was developed. (C) 1996 American Institute of Physics.