Calorimetric study of hydrogen interaction with Sm2Fe17

Study of Hydrogen Interactions with Nd2Fe17 and Nd2Fe14B by Means of Calorimetric Method

“…The calorimetric results that we obtained in the present work and in previous studies [8,10] are consistent with the data obtained in reference [4]. We may assume that hydrogen atoms fill 9e sites during absorption at 200 and 250 • C at the range of hydrogen concentration of 0 < C < 2.0 (∆Habs.…”

“…In other words, in the Nd 2 Fe 17 -H 2 system, there is a small pressure hysteresis. Previously, we observed such hysteresis in the Sm 2 Fe 17 -H 2 system at 250 • C [10] and Nd 2 Fe 17 -H 2 system at 200 • C [8]. We obtained the following values of hysteresis for the Nd 2 Fe 17 -H 2 system at 200 and 250 • C at a hydrogen concentration C~3.6 ln(10/4.9) = 0.84 and ln(13/10) = 0.60, respectively.…”

“…= f(C) (see Figure 3a-c and Table 1). The data which we obtained earlier for the Nd 2 Fe 17 -H 2 system at 200 • C [10] are presented in Table 1. Analyzing the data presented in the Table 1 and Figure 3a-c, it should be noted that in the Previously, Isnard et al [26,27] investigated the hydride phases of R 2 Fe 17 , where R is the light rare-earth element with rhombohedral structure R-3m, by means of neutron diffraction analysis and determined that hydrogen atoms in these intermetallic compounds occupied octahedral 9e and tetrahedral 18g sites.…”

“…In the present work, we continue our research of hydrogen interaction with the systems of R 2 Fe 17 and Nd 2 Fe 14 B [8][9][10] and summarize the obtained results.…”

“…Comparing results of the calorimetric study for the Nd 2 Fe 17 -H 2 and for Sm 2 Fe 17 -H 2 systems (presented in Table 2 made on the basis of the results in reference [10]), one can notice that the values of ∆Habs. (des.)…”