We have studied the effect of nitriding of Nd2Fe14B by X-rav diffraction (XRD), Mossbauer spectroscopy, vibrating sample magnetometry (VSM) and transmission electron microscopy (TEM). Samples were nitrided in an atmosphere of NH3 gas flow at temperatures between 300 and 500-degrees-C. In the samples nitrided between 350 and 400-degrees-C the formation of the Nd2Fe14BNx 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 Fe-57 in the Nd2Fe14BNx phase is 1%-3% as compared with the Nd2Fe14B phase. This result is consistent with the result from VSM measurements that the Curie temperature of Nd2Fe14BNx is about 20-degrees-C higher than that of Nd2Fe14B. For the samples nitrided above 375-degrees-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.
