The structures and electrochemical properties of the Ti1.4V0.6Ni ribbon before and after heat treatment are investigated systematically. The structure of the sample is characterized by X-ray powder diffraction analysi...The structures and electrochemical properties of the Ti1.4V0.6Ni ribbon before and after heat treatment are investigated systematically. The structure of the sample is characterized by X-ray powder diffraction analysis. Electrochemical properties including the discharge capacity, the cyclic stability and the high-rate discharge ability are tested. X-ray powder diffraction analysis shows that after heat treatment at 590 °C for 30 min, all samples mainly consist of the icosahedral quasicrystal phase (I-phase), Ti2Ni phase (FCC), V-based solid solution phase (BCC) and C14 Laves phase (hexagonal). Electrochemical measurements show that the maximum discharge capacity of the alloy electrode after heat treatment is 330.9 mA?h/g under the conditions that the discharge current density is 30 mA/g and the temperature is 30 °C. The result indicates that the cyclic stability and the high-rate discharge ability are all improved. In addition, the electrochemical kinetics of the alloy electrode is also studied by electrochemical impedance spectroscopy (EIS) and hydrogen diffusion coefficient (D).展开更多
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
The large disc LaFe11.6Si1.4 alloy, which was prepared by medium-frequency induction furnace, was annealed at 1503 K for different time. The main phases were 1：13 phase in the edge parts of the large discs alloy; the...The large disc LaFe11.6Si1.4 alloy, which was prepared by medium-frequency induction furnace, was annealed at 1503 K for different time. The main phases were 1：13 phase in the edge parts of the large discs alloy; the impurity phases included α-Fe phase, LaFeSi phase, and even very small amount of La5Si3 phase. The amounts of impurity phases reduced with increasing in annealing time. The magnetic properties in the edge parts of the large discs LaFe11.6Si1.4 alloy were investigated. The magnetic susceptibility had an abrupt change at Curie temperature（TC） as the magnetization in M-T curves. The alloys had almost the same TC（191 K）, the magnetocaloric effect（MCE） and relative cooling power（RCP） increased with increasing in annealing time. In addition, for the same alloy, the magnetic hysteresis decreased with the increase in temperature.展开更多
The morphology analysis and electrochemical method were used to study the corrosion behavior of LaFe11.6Si1.4 alloy of copper ion implantation. X-ray photoelectron spectroscopy （XPS） and atomic emission spectroscopy...The morphology analysis and electrochemical method were used to study the corrosion behavior of LaFe11.6Si1.4 alloy of copper ion implantation. X-ray photoelectron spectroscopy （XPS） and atomic emission spectroscopy （AES） research results showed that a 15 nm-thick oxide film was formed on the surface of sample, and the copper content reached the highest value at 60 nm with a normal distribution. Immersion experiments indicated that the corrosion happened in the copper-poor zone firstly and a galvanic connection was formed among different zones on the surface due to the inhomogeneous distribution of copper. Electrochemical experiment results showed that the corrosion was serious when the ion acceleration voltage increased, and the high acceleration could reduce the thermodynamic performance of corrosion of LaFe11.6Si1.4 alloy.展开更多
基金Project (20112216120001) supported by the Doctoral Program of Tertiary Education of the Ministry of Education of ChinaProject(21215141) supported by the Natural Science Foundation of Jilin Province, China+3 种基金Project (20921002) supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of ChinaProjects (21073179, 61106050) supported by the National Natural Science Foundation of ChinaProject (BE2012047) supported by Scientific and Technological Supporting Program of Jiangsu Province of China and GS Yuasa Corporation of JapanProject (11KZ38) supported by and Scientific and Technological Pillar Project of Changchun, China
文摘The structures and electrochemical properties of the Ti1.4V0.6Ni ribbon before and after heat treatment are investigated systematically. The structure of the sample is characterized by X-ray powder diffraction analysis. Electrochemical properties including the discharge capacity, the cyclic stability and the high-rate discharge ability are tested. X-ray powder diffraction analysis shows that after heat treatment at 590 °C for 30 min, all samples mainly consist of the icosahedral quasicrystal phase (I-phase), Ti2Ni phase (FCC), V-based solid solution phase (BCC) and C14 Laves phase (hexagonal). Electrochemical measurements show that the maximum discharge capacity of the alloy electrode after heat treatment is 330.9 mA?h/g under the conditions that the discharge current density is 30 mA/g and the temperature is 30 °C. The result indicates that the cyclic stability and the high-rate discharge ability are all improved. In addition, the electrochemical kinetics of the alloy electrode is also studied by electrochemical impedance spectroscopy (EIS) and hydrogen diffusion coefficient (D).
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Project supported by the National Natural Science Foundation of China(51176050)China Postdoctoral Science Foundation(2013M542274)
文摘The large disc LaFe11.6Si1.4 alloy, which was prepared by medium-frequency induction furnace, was annealed at 1503 K for different time. The main phases were 1：13 phase in the edge parts of the large discs alloy; the impurity phases included α-Fe phase, LaFeSi phase, and even very small amount of La5Si3 phase. The amounts of impurity phases reduced with increasing in annealing time. The magnetic properties in the edge parts of the large discs LaFe11.6Si1.4 alloy were investigated. The magnetic susceptibility had an abrupt change at Curie temperature（TC） as the magnetization in M-T curves. The alloys had almost the same TC（191 K）, the magnetocaloric effect（MCE） and relative cooling power（RCP） increased with increasing in annealing time. In addition, for the same alloy, the magnetic hysteresis decreased with the increase in temperature.
基金Project supported by the Key Project of National Natural Science Foundation of China (50731007)the National High Technology Research and Development Program of China (2007AA03Z440)
文摘The morphology analysis and electrochemical method were used to study the corrosion behavior of LaFe11.6Si1.4 alloy of copper ion implantation. X-ray photoelectron spectroscopy （XPS） and atomic emission spectroscopy （AES） research results showed that a 15 nm-thick oxide film was formed on the surface of sample, and the copper content reached the highest value at 60 nm with a normal distribution. Immersion experiments indicated that the corrosion happened in the copper-poor zone firstly and a galvanic connection was formed among different zones on the surface due to the inhomogeneous distribution of copper. Electrochemical experiment results showed that the corrosion was serious when the ion acceleration voltage increased, and the high acceleration could reduce the thermodynamic performance of corrosion of LaFe11.6Si1.4 alloy.
