The effects of solidification rate and excessive Fe on phase formation and magnetocaloric properties of LaFe11.6xSi1.4(x=1.1,1.2)were investigated by XRD,SEM and VSM measurements.The XRD results show that the amount o...The effects of solidification rate and excessive Fe on phase formation and magnetocaloric properties of LaFe11.6xSi1.4(x=1.1,1.2)were investigated by XRD,SEM and VSM measurements.The XRD results show that the amount of LaFeSi phase in the as-cast melt-spun ribbons prepared by a copper wheel at a speed of10m/s is less than that in the as-cast arc melting buttons with the same x values.The annealed melt-spun ribbons contain smaller amount of La(Fe,Si)13(1:13)phase than the corresponding annealed arc melting buttons.Although the melt-spun sample has finer crystalline grains ofα-Fe,as indicated by SEM analysis,its crystalline size has not reached nano-scale.Therefore,the magnetic exchange-coupling between1:13phase andα-Fe phase has not been observed in melt-spun ribbons.Further,the maximum negative magnetic entropy change(?SMax)and relative cooling power(RCP)of annealed melt-spun ribbons under a field change of0?2T are weaker than those of the corresponding annealed arc melting buttons.展开更多
In the present study,porous bulk palladium samples were prepared by sodium chloride salt powder spacer incorporation and removal combined with dealloying.The obtained porous Pd bulks were characterized by X‐ray diffr...In the present study,porous bulk palladium samples were prepared by sodium chloride salt powder spacer incorporation and removal combined with dealloying.The obtained porous Pd bulks were characterized by X‐ray diffraction,field‐emission scanning electron microscopy and N2adsorption isotherm measurements.The prepared porous Pd bulk samples showed a hierarchical pore structure,a high porosity of^88%,a high surface area of^54m2/g,and a compression strength of^0.5MPa.Electrochemical measurements were performed to evaluate the electrocatalytic properties of the porous Pd bulk samples,revealing their effectiveness for ethanol oxidation.展开更多
基金Project (16ZB0301) supported by the Research Program of Sichuan Provincial Education Department,China
文摘The effects of solidification rate and excessive Fe on phase formation and magnetocaloric properties of LaFe11.6xSi1.4(x=1.1,1.2)were investigated by XRD,SEM and VSM measurements.The XRD results show that the amount of LaFeSi phase in the as-cast melt-spun ribbons prepared by a copper wheel at a speed of10m/s is less than that in the as-cast arc melting buttons with the same x values.The annealed melt-spun ribbons contain smaller amount of La(Fe,Si)13(1:13)phase than the corresponding annealed arc melting buttons.Although the melt-spun sample has finer crystalline grains ofα-Fe,as indicated by SEM analysis,its crystalline size has not reached nano-scale.Therefore,the magnetic exchange-coupling between1:13phase andα-Fe phase has not been observed in melt-spun ribbons.Further,the maximum negative magnetic entropy change(?SMax)and relative cooling power(RCP)of annealed melt-spun ribbons under a field change of0?2T are weaker than those of the corresponding annealed arc melting buttons.
基金supported by the National Natural Science Foundation of China(11572057)the School Foundation of Chengdu University(2080516030)~~
文摘In the present study,porous bulk palladium samples were prepared by sodium chloride salt powder spacer incorporation and removal combined with dealloying.The obtained porous Pd bulks were characterized by X‐ray diffraction,field‐emission scanning electron microscopy and N2adsorption isotherm measurements.The prepared porous Pd bulk samples showed a hierarchical pore structure,a high porosity of^88%,a high surface area of^54m2/g,and a compression strength of^0.5MPa.Electrochemical measurements were performed to evaluate the electrocatalytic properties of the porous Pd bulk samples,revealing their effectiveness for ethanol oxidation.
