In situ neutron diffraction study of the reaction of the compounds NdFe10.75V1.25 and NdFe11Ti with nitrogen

The nitrogenation and nitrogen disproportionation behavior of NdFe11Ti and NdFe10.75V1.25 was investigated by in situ neutron powder diffraction at temperatures between 100 and 800°C. The nitrogen content and lattice parameters were measured as a function of temperature and time. In both compounds, the nitrogen disproportionation starts before the interstitial modification is complete. The product of the nitrogen disproportionation is a mixture of α-Fe and an amorphous phase, which is stable up to temperatures of 800°C.