In this paper, we study the effects of Pr substitution on the hydrogenating process and magnetocaloric properties of La_(1-x)Pr_xFe_(11.4)Si_(1.6)H_y hydrides. The powder x-ray diffraction patterns of the La_(1-x)Pr_x...In this paper, we study the effects of Pr substitution on the hydrogenating process and magnetocaloric properties of La_(1-x)Pr_xFe_(11.4)Si_(1.6)H_y hydrides. The powder x-ray diffraction patterns of the La_(1-x)Pr_xFe_(11.4)Si_(1.6) and its hydrides show that each of the alloys is crystallized into the single phase of cubic Na Zn_(13)-type structure. There are hydrogen-absorbing plateaus under 0.4938 MPa and 0.4882 MPa in the absorbing curves for the La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6) and La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6) compounds. The releasing processes lag behind the absorbing process, which is obviously different from the coincidence between absorbing and releasing curves of the La Fe_(11.4)Si_(1.6) compound. The remnant hydrogen content for La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6) is significantly more than that for La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6) after hydrogen desorption, indicating that more substitutions of Pr for La are beneficial to retaining more hydrogen atoms in the alloys. The values of maximum magnetic entropy change are 14.91 J/kg·K and 17.995 J/kg·K for La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6)H_(0.13) and La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6)H_(0.87),respectively.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51301008 and 51171003)the Beijing Natural Science Foundation,China(Grant No.1112005)
文摘In this paper, we study the effects of Pr substitution on the hydrogenating process and magnetocaloric properties of La_(1-x)Pr_xFe_(11.4)Si_(1.6)H_y hydrides. The powder x-ray diffraction patterns of the La_(1-x)Pr_xFe_(11.4)Si_(1.6) and its hydrides show that each of the alloys is crystallized into the single phase of cubic Na Zn_(13)-type structure. There are hydrogen-absorbing plateaus under 0.4938 MPa and 0.4882 MPa in the absorbing curves for the La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6) and La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6) compounds. The releasing processes lag behind the absorbing process, which is obviously different from the coincidence between absorbing and releasing curves of the La Fe_(11.4)Si_(1.6) compound. The remnant hydrogen content for La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6) is significantly more than that for La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6) after hydrogen desorption, indicating that more substitutions of Pr for La are beneficial to retaining more hydrogen atoms in the alloys. The values of maximum magnetic entropy change are 14.91 J/kg·K and 17.995 J/kg·K for La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6)H_(0.13) and La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6)H_(0.87),respectively.
