QUANTITATIVE-ANALYSIS OF THE NITROGENATION PROCESS IN Y2FE17NX BASED ON A 2-REGION CONFIGURATION

A quantitative analysis has been carried out for the nitrogenation pro cess using two groups of Y2Fe17Nx samples, one obtained by successivel y allowing longer nitrogenation times and the other by systematically varying the particle size. A detailed calculation using the two-region model results in an analytical solution for the nitrogen distribution as a function of nitrogenation time and particle size, which agrees w ith the observations in both groups of samples. This model describes t he entire nitrogenation process (usually longer than 10 h), and predic ts a diffusion parameter D-0 with the correct order of magnitude (simi lar to 10(-6) m(2)/s). (C) 1997 American Institute of Physics.