A detailed study of the nitrogenation of the Fe/sub 17/R/sub 2/ phases (R=Sm, Gd, Ho and Tb)

Early studies in the 17:2 phases based on Pr, Nd and Sm for relatively low absorption temperature (400/spl deg/C) showed that the diffusion pattern is different from the shell-core model. Instead, the diffusion occurs at phase and grain boundaries. The precipitation of the saturated phase occurs along these boundaries. In this work we show, using different characterization methods, that the same behavior is observed for the 17:2 phases based on Sm, Gd, Ho, Tb.