The cyclic voltammetry, chronopotentiometry and chronoamperometry were used to study the behaviors of Fe 2+ on Pt, Cu, Ag and Ti electrodes in urea NaBr melt at 373 K. Electroreduction of Fe 2+ to metallic ...The cyclic voltammetry, chronopotentiometry and chronoamperometry were used to study the behaviors of Fe 2+ on Pt, Cu, Ag and Ti electrodes in urea NaBr melt at 373 K. Electroreduction of Fe 2+ to metallic Fe is irreversible in one step. The exchange current density determined on Ti electrode is 2 68×10 -5 A·cm -2 . Sm 3+ does not reduce to Sm alone, but can be inductively codeposited with Fe 2+ . Sm Fe alloy film contained over 90% Sm (mass fraction) can be obtained by potentiostatic electrolysis and galvanostatic electrolysis on Cu substrate. The Sm content in the alloy is related to the cathode potential, current density and the Sm 3+ /Fe 2+ molar ratio. The surface state of the Sm Fe deposit was studied by scanning electron microscopy.展开更多
Nanocrystalline SmFe_（8.95-x）Ga_（0.26）Nb_xN_δ（x=0, 0.1, 0.2, 0.3） were prepared using rapid-quenching,annealing and nitriding. The magnetic properties and crystal structures were systematically studied under va...Nanocrystalline SmFe_（8.95-x）Ga_（0.26）Nb_xN_δ（x=0, 0.1, 0.2, 0.3） were prepared using rapid-quenching,annealing and nitriding. The magnetic properties and crystal structures were systematically studied under various wheel velocities to investigate the influence of Nb doping for the compounds. It is found that TbCu7-type structure is able to be obtained even though the wheel velocity is reduced to 20 m/s（x = 0.3）. An significant increase（△T_c=70 ℃） of the Curie temperature is obtained with Nb doping at x = 0.1 due to the lattice expansion revealed by Rietveld analysis. The optimum coercivity with the value H_（cj） of 810 kA/m is achieved at x = 0.2 in the nitrides, in which a reasonable distribution of grain sizes of both TbCu_7-type SmFe_9 N_δ and α-Fe can be found. However, an excess of Nb doping may lead to the increase of the weight fraction of α-Fe, which in turn deteriorates the magnetic properties.展开更多
文摘The cyclic voltammetry, chronopotentiometry and chronoamperometry were used to study the behaviors of Fe 2+ on Pt, Cu, Ag and Ti electrodes in urea NaBr melt at 373 K. Electroreduction of Fe 2+ to metallic Fe is irreversible in one step. The exchange current density determined on Ti electrode is 2 68×10 -5 A·cm -2 . Sm 3+ does not reduce to Sm alone, but can be inductively codeposited with Fe 2+ . Sm Fe alloy film contained over 90% Sm (mass fraction) can be obtained by potentiostatic electrolysis and galvanostatic electrolysis on Cu substrate. The Sm content in the alloy is related to the cathode potential, current density and the Sm 3+ /Fe 2+ molar ratio. The surface state of the Sm Fe deposit was studied by scanning electron microscopy.
文摘Nanocrystalline SmFe_（8.95-x）Ga_（0.26）Nb_xN_δ（x=0, 0.1, 0.2, 0.3） were prepared using rapid-quenching,annealing and nitriding. The magnetic properties and crystal structures were systematically studied under various wheel velocities to investigate the influence of Nb doping for the compounds. It is found that TbCu7-type structure is able to be obtained even though the wheel velocity is reduced to 20 m/s（x = 0.3）. An significant increase（△T_c=70 ℃） of the Curie temperature is obtained with Nb doping at x = 0.1 due to the lattice expansion revealed by Rietveld analysis. The optimum coercivity with the value H_（cj） of 810 kA/m is achieved at x = 0.2 in the nitrides, in which a reasonable distribution of grain sizes of both TbCu_7-type SmFe_9 N_δ and α-Fe can be found. However, an excess of Nb doping may lead to the increase of the weight fraction of α-Fe, which in turn deteriorates the magnetic properties.
