Nitriding of Nd2Fe14B

Abstract We have studied the effect of nitriding of Nd 2 Fe 14 B by X-ray diffraction (XRD), Mossbauer spectroscopy, vibrating sample magnetometry (VSM) and transmission electron microscopy (TEM). Samples were nitrided in an atmosphere of NH 3 gas flow at temperatures between 300 and 500 °C. In the samples nitrided between 350 and 400 °C the formation of the Nd 2 Fe 14 BN x phase is assured by the extension of the lattice constant by 0.2%–0.7%. Mossbauer spectroscopy shows that the increment in the hyperfine magnetic field of 57 Fe in the Nd 2 Fe 14 BN x phase is 1%–3% as compared with the Nd 2 Fe 14 B phase. This result is consistent with the result from VSM measurements that the Curie temperature of Nd 2 Fe 14 BN x is about 20 °C higher than that of Nd 2 Fe 14 B. For the samples nitrided above 375 °C a paramagnetic doublet is observed in the Mossbauer spectra at room temperature. The XRD profile of the sample has a broad pattern. TEM observation indicates that the sample is almost amorphous.