Magnetic properties and structures of HDDR NdFeCoBNbZr alloys

The magnetic properties and the microstructures of HDDR magnet materials fabricated from the alloys with chemical composition of Nd14FebalCo15B6.5NbxZry (x = 0–0.25; y = 0–0.25) have been investigated. The variation of the magnetic properties of the magnets with HD temperature and DR temperature was studied. The results show that HD temperature and DR temperature affect the magnetic properties of HDDR magnet powders obviously. The analysis of XRD spectra shows that the process of HDDR technique is hydrogenation disproportionation desorption recombination. The addition of a small amount of Nb element is useful to improve the magnetic properties of HDDR magnetic powders. And the composite addition of a little Nb and Zr can further enhance the magnetic properties. The reasons for the enhancement of the magnetic properties by the composite addition of small amounts of Nb and Zr are analyzed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)