Isothermal Section Of The Gd-Fe-Mn System At500℃and Electrochemical Performance Of Their Alloys

The isothermal section of the phase diagram of the Gd-Fe-Mn ternary system at500℃was investigated by powder X-ray diffraction (XRD), metallographic analysis, scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The experimental results show that the isothermal section consists of9single-phase regions,13two-phase regions and5three-phase regions. Two pairs of corresponding compounds of Gd-Fe and Gd-Mn systems, i.e., GdFe2and GdMn2, Gd6Fe23and Gd6Mn23form a continuous series of solid solution at500℃. The alloy Gd2Fe17-xMnx was found to have a wide homogeneity range from0to51at.%Mn and the alloy GdMn12-xFex was also observed to have a wide homogeneity range from0to79at.%Fe. The solid solubility of Mn in (yFe) is ranged from18to28at.%. The maximum solid solubilities of Mn in (aFe), GdFe3and Fe in (aMn) were determined to be about11at.%Mn,4at.%Mn and42at.%Fe, respectively. No new ternary compound was found in all ternary alloy samples.The automatic battery testing instrument was used to investigated the electrochemical performance of the alloys Gd2Fe17-xMnx (x=0,1,3) and Gd6Fe23-xMnx(x=0,3,9,14,17,20), such as activation performance, discharge capacity, high rate discharge ability and cycling stable performance. By comparing all the testing results, it was found that the alloy Gd6Fe6Mn17has higher discharge capacity and better cycle stability.