DIFFUSION OF NITROGEN IN R(2)FE(17) (R=RARE EARTH) COMPOUNDS DETERMINED BY THE KISSINGER METHOD

The activation energy of nitrogen diffusion in R(2)Fe(17) (R=rare earth) compounds has been determined by applying the Kissinger method to analyse the differential scanning calorimetry (DSC) traces of nitrogenated R(2)Fe(17) compounds. The nitrogen outgas that starts when the nitrides are heated above about 300 degrees C is a typical decomposition reaction of the type solid --> solid + gas to which the Kissinger method can be applied. From the heating-rate dependence of the endothermic peaks in the DSC curves, values for the activation energy of nitrogen diffusion are derived. There is good agreement between the results for Sm2Fe17 and Nd2Fe17 obtained in the present investigation and the results reported in the literature which were obtained by means bf other methods.