In order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloys,Ni in the alloy is substituted by element Co. The nanocrystalline and amorphous Mg2Ni-type Mg2Ni1-xCox (x=0,0.1,0.2,0.3,0.4) alloys w...In order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloys,Ni in the alloy is substituted by element Co. The nanocrystalline and amorphous Mg2Ni-type Mg2Ni1-xCox (x=0,0.1,0.2,0.3,0.4) alloys were synthesized by melt-spinning technique. The structures of the as-cast and spun alloys were studied with an X-ray diffractometer (XRD) and a high resolution transmission electronic microscope (HRTEM). An investigation on the thermal stability of the as-spun alloys was carried out with a differential scanning calorimeter (DSC). The hydrogen absorption and desorption kinetics of the alloys were measured with an automatically controlled Sieverts apparatus. The results demonstrate that the substitution of Co for Ni does not alter the major phase of Mg2Ni but results in the formation of secondary phase MgCo2. No amorphous phase is detected in the as-spun Co-free alloy,but a certain amount of amorphous phase is clearly found in the as-spun Co-containing alloys. The substitution of Co for Ni exerts a slight influence on the hydriding kinetics of the as-spun alloy. However,it dramatically enhances the dehydriding kinetics of the as-cast and spun alloys. As Co content (x) increases from 0 to 0.4,the hydrogen desorption capacity increases from 0.19% to 1.39% (mass fraction) in 20 min for the as-cast alloy,and from 0.89% to 2.18% (mass fraction) for the as-spun alloy (30 m/s).展开更多
A series of the amorphous Gd75-55A125-5Fe0-40 alloy ribbons were prepared by melt spinning. The structure, magnetic properties and magnetocaloric effect （MCE） of these alloys were investigated. The prepared samples ...A series of the amorphous Gd75-55A125-5Fe0-40 alloy ribbons were prepared by melt spinning. The structure, magnetic properties and magnetocaloric effect （MCE） of these alloys were investigated. The prepared samples have shown the characteristics of a second-order phase transition with zero hysteresis loss and the Tc can be tuned by changing the Fe contents. For the different compositions, the magnetic entropy change （-△Sm） for a field change of 0-5 T reached a maximum value of 7.14 J kg 1 K1 in the Gd70A120Fel0 alloy near its Curie temperature （To） of 149 K. The non-linear composition dependence of （- △ Sin） could be caused by the competitions between Fe-Fe, Fe-Gd and Gd-Gd interactions. The refrigeration capacity （RC） values of these al- loys are about 532-780 J/kg under a magnetic field change of 0-5 T. The results indicate that amorphous GdFeA1 alloys can be considered as ideal candidates for a magnetic refrigerant in the temperature range of 104-222 K.展开更多
This paper reports on the preparation of Fe82.7-85.7Si2-4.9B9.2-11.2P1.5.2.7C0,8 soft magnetic amorphous alloys with a distinctly high Fe content of 93.5-95.5 wt.% by component design and composition adjustment. All a...This paper reports on the preparation of Fe82.7-85.7Si2-4.9B9.2-11.2P1.5.2.7C0,8 soft magnetic amorphous alloys with a distinctly high Fe content of 93.5-95.5 wt.% by component design and composition adjustment. All alloys can be readily fabricated into completely amorphous ribbon samples with good surface quality by the single copper roller melt-spinning method. These alloys show good bending ductility and excellent magnetic properties after annealing, i.e., low coercivity （He） of 3.3-5.9 A/m, high permeability （μe） of 5000-10000 and high flux saturation density （Bs） of 1.63-1.66 T. The mechanism of the good glass forming ability （GFA）and soft-magnetic properties are explored. The amorphous alloys with the high Fe content comparable to that of the desired high Si alloy can be promising candidates for the potential application in electric devices.展开更多
基金Project(2006AA05Z132) supported by the National High-tech Research and Development Program of ChinaProjects(50871050, 50961009) supported by the National Natural Science Foundation of China+1 种基金Project(2010ZD05) supported by the Natural Science Foundation of Inner Mongolia, ChinaProject(NJzy08071) supported by the High Education Science Research Program of Inner Mongolia, China
文摘In order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloys,Ni in the alloy is substituted by element Co. The nanocrystalline and amorphous Mg2Ni-type Mg2Ni1-xCox (x=0,0.1,0.2,0.3,0.4) alloys were synthesized by melt-spinning technique. The structures of the as-cast and spun alloys were studied with an X-ray diffractometer (XRD) and a high resolution transmission electronic microscope (HRTEM). An investigation on the thermal stability of the as-spun alloys was carried out with a differential scanning calorimeter (DSC). The hydrogen absorption and desorption kinetics of the alloys were measured with an automatically controlled Sieverts apparatus. The results demonstrate that the substitution of Co for Ni does not alter the major phase of Mg2Ni but results in the formation of secondary phase MgCo2. No amorphous phase is detected in the as-spun Co-free alloy,but a certain amount of amorphous phase is clearly found in the as-spun Co-containing alloys. The substitution of Co for Ni exerts a slight influence on the hydriding kinetics of the as-spun alloy. However,it dramatically enhances the dehydriding kinetics of the as-cast and spun alloys. As Co content (x) increases from 0 to 0.4,the hydrogen desorption capacity increases from 0.19% to 1.39% (mass fraction) in 20 min for the as-cast alloy,and from 0.89% to 2.18% (mass fraction) for the as-spun alloy (30 m/s).
基金supported by the Guangdong Provincial Science and Technology Program (Grant Nos. 2010B050300008, 2007B010600043)the Fundamental Research Funds for the Central Universities, South China University of Technology (Grant No. 2009ZM0291)
文摘A series of the amorphous Gd75-55A125-5Fe0-40 alloy ribbons were prepared by melt spinning. The structure, magnetic properties and magnetocaloric effect （MCE） of these alloys were investigated. The prepared samples have shown the characteristics of a second-order phase transition with zero hysteresis loss and the Tc can be tuned by changing the Fe contents. For the different compositions, the magnetic entropy change （-△Sm） for a field change of 0-5 T reached a maximum value of 7.14 J kg 1 K1 in the Gd70A120Fel0 alloy near its Curie temperature （To） of 149 K. The non-linear composition dependence of （- △ Sin） could be caused by the competitions between Fe-Fe, Fe-Gd and Gd-Gd interactions. The refrigeration capacity （RC） values of these al- loys are about 532-780 J/kg under a magnetic field change of 0-5 T. The results indicate that amorphous GdFeA1 alloys can be considered as ideal candidates for a magnetic refrigerant in the temperature range of 104-222 K.
基金the National Natural Science Foundation of China(Grant No.51541106)Ningbo International Cooperation Projects(Grant No.2015D10022)+2 种基金Ningbo Major Project for Science and Technology(Grant No.201401B1003003)Ningbo Natural Science Foundations(Grant No.2015A610007)General Research Fund of Hong Kong(Grant No.CityU 102013)
文摘This paper reports on the preparation of Fe82.7-85.7Si2-4.9B9.2-11.2P1.5.2.7C0,8 soft magnetic amorphous alloys with a distinctly high Fe content of 93.5-95.5 wt.% by component design and composition adjustment. All alloys can be readily fabricated into completely amorphous ribbon samples with good surface quality by the single copper roller melt-spinning method. These alloys show good bending ductility and excellent magnetic properties after annealing, i.e., low coercivity （He） of 3.3-5.9 A/m, high permeability （μe） of 5000-10000 and high flux saturation density （Bs） of 1.63-1.66 T. The mechanism of the good glass forming ability （GFA）and soft-magnetic properties are explored. The amorphous alloys with the high Fe content comparable to that of the desired high Si alloy can be promising candidates for the potential application in electric devices.
