MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2＋, Ni2＋, and Fe2＋ in the lye. The phase, morphology, an...MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2＋, Ni2＋, and Fe2＋ in the lye. The phase, morphology, and particle diameter were examined by the X-ray diffraction and transmission electron microscopy. The magnetic properties of the samples were studied using a vibrating sample magnetometer. nanorods with a diameter of 35 nm and an The results indicated that pure Ni0.5-xZn0.5Fe2O4 aspect ratio of 15 were prepared. It was found that the diametei of the MnxNi0.5-xZn0.5Fe2O4（0≤x≤0.5） samples increased, the length and the aspect .ratio decreased, with an increase in x value. When x=0.5, the diameter and the aspect ratio of the sample reached up to 50 nm and 7-8, respectively. The coercivity of the samples first increased and then decreased with the increase in the x value. The coercivity of the samples again increased when the x value was higher than 0.4. When x=0.5, the coercivity of the MnxNi0.5-xZn0.5Fe2O4 sample reached the maximal value （134.3 Oe） at the calcination temperature of 600 ℃. The saturation magnetization of the samples first increased and then. decreased with the increase in the x value. When x=0.2, the saturation magnetizat：ion of the sample reached the maximal value （68.5 emu/g） at the calcination temperature of 800 ℃.展开更多
Novel, low-cost Fe0/ZSM-5-based particles and porous tablets were prepared by a ballmilling method and used for the removal of Pb^2＋ in solution. Solid-phase characterization by scanning electron microscopy coupled w...Novel, low-cost Fe0/ZSM-5-based particles and porous tablets were prepared by a ballmilling method and used for the removal of Pb^2＋ in solution. Solid-phase characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy（SEMEDS） and transmission electron microscopy（TEM） revealed that the Fe0 microparticles were evenly loaded and tightly immobilized on the surface of ZSM-5 because of the extrusion/welding impact during ball-milling. For different Pb2＋ concentrations, batch experiments indicated that the removal of Pb2＋ increased with the decline of dissolved Fe2＋and p H value in the solution for particles; opposite results were obtained for the tablets. The differences in the contact between both materials and Pb2＋ were the main factor controlling Pb2＋ removal in the solution. Investigation into the effect of initial pH value revealed that high pH reduced the number of electrons released from Fe corrosion. Consequently, low levels of removed Pb2＋ and dissolved Fe2＋ were synchronously observed. Also, simulated electroplating wastewater was treated using the prepared particles and porous tablets,and the removal order of Pb^2＋ 〉 Cr6^＋〉 Cu^2＋≈ Cd^2＋ was observed. The Fe0/ZSM-5 particles and tablets prepared through ball-milling show potential as materials for treatment of Pb2＋ and other toxic metals.展开更多
Crystallization behaviors of Ce60Al15Fe5+xCo20-x(x=0,5,10) bulk metallic glasses(BMGs) were studied by means of differential scanning calorimeter(DSC) and X-ray diffraction(XRD).The crystallization processes of differ...Crystallization behaviors of Ce60Al15Fe5+xCo20-x(x=0,5,10) bulk metallic glasses(BMGs) were studied by means of differential scanning calorimeter(DSC) and X-ray diffraction(XRD).The crystallization processes of different samples were simulated by JMA equation.Experimental results demonstrated that incubation and crystallization time increased with decreasing isothermal temperature for the same sample.The crystallization mechanism of CeAlFeCo BMGs was discussed.展开更多
FesoMn15-xCoxNi35 （x=0, 1, 3, 5, 7） alloys were prepared by arc melting under purified argon atmosphere. The ingots were homogenized at 930℃ for 90 h followed by water quenching. The crystal structure, magnetic pro...FesoMn15-xCoxNi35 （x=0, 1, 3, 5, 7） alloys were prepared by arc melting under purified argon atmosphere. The ingots were homogenized at 930℃ for 90 h followed by water quenching. The crystal structure, magnetic properties and magnetocaloric effects of the alloys were studied by X-ray diffraction （XRD） and MPMS-7-type SQUID. The results show that all samples still maintained a single γ-（Fe, Ni）-type phase structure. With the increase of the content of Co, the Curie temperatures of these alloys increased and exhibited a second-order magnetic transition from ferromagnetic （FM） to paramagnetic （PM） state near Curie temperature. The maximum magnetic entropy change and the relative cooling power of Fe50Mn10CosNi35 alloy was 2.55 J/kg.K and 181 J/kg, respectively, for an external field change of 5 T. Compared with rare earth metal Gd, FesoMnls-xCoxNi35 series of alloys have obvious advantage in resource price; their Curie temperatures can be tuned to near room temperature, maintain a relatively large magnetic entropy change at the same time and they are a type of potential magnetic refrigeration materials near room temperature.展开更多
文摘MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2＋, Ni2＋, and Fe2＋ in the lye. The phase, morphology, and particle diameter were examined by the X-ray diffraction and transmission electron microscopy. The magnetic properties of the samples were studied using a vibrating sample magnetometer. nanorods with a diameter of 35 nm and an The results indicated that pure Ni0.5-xZn0.5Fe2O4 aspect ratio of 15 were prepared. It was found that the diametei of the MnxNi0.5-xZn0.5Fe2O4（0≤x≤0.5） samples increased, the length and the aspect .ratio decreased, with an increase in x value. When x=0.5, the diameter and the aspect ratio of the sample reached up to 50 nm and 7-8, respectively. The coercivity of the samples first increased and then decreased with the increase in the x value. The coercivity of the samples again increased when the x value was higher than 0.4. When x=0.5, the coercivity of the MnxNi0.5-xZn0.5Fe2O4 sample reached the maximal value （134.3 Oe） at the calcination temperature of 600 ℃. The saturation magnetization of the samples first increased and then. decreased with the increase in the x value. When x=0.2, the saturation magnetizat：ion of the sample reached the maximal value （68.5 emu/g） at the calcination temperature of 800 ℃.
基金National “863” Program(2011AA11A256)the National Science Foundation of China(21373028,51302014)+1 种基金New Century Educational Talents Plan of Chinese Education Ministry(NCET-12-0050)Beijing Novel Program(Z121103002512029)
基金supported by the National Natural Science Foundation of China(Nos.51378180,21677162)
文摘Novel, low-cost Fe0/ZSM-5-based particles and porous tablets were prepared by a ballmilling method and used for the removal of Pb^2＋ in solution. Solid-phase characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy（SEMEDS） and transmission electron microscopy（TEM） revealed that the Fe0 microparticles were evenly loaded and tightly immobilized on the surface of ZSM-5 because of the extrusion/welding impact during ball-milling. For different Pb2＋ concentrations, batch experiments indicated that the removal of Pb2＋ increased with the decline of dissolved Fe2＋and p H value in the solution for particles; opposite results were obtained for the tablets. The differences in the contact between both materials and Pb2＋ were the main factor controlling Pb2＋ removal in the solution. Investigation into the effect of initial pH value revealed that high pH reduced the number of electrons released from Fe corrosion. Consequently, low levels of removed Pb2＋ and dissolved Fe2＋ were synchronously observed. Also, simulated electroplating wastewater was treated using the prepared particles and porous tablets,and the removal order of Pb^2＋ 〉 Cr6^＋〉 Cu^2＋≈ Cd^2＋ was observed. The Fe0/ZSM-5 particles and tablets prepared through ball-milling show potential as materials for treatment of Pb2＋ and other toxic metals.
基金supported by the Foundation of Science & Technology Department of Henan Province (082102230035)
文摘Crystallization behaviors of Ce60Al15Fe5+xCo20-x(x=0,5,10) bulk metallic glasses(BMGs) were studied by means of differential scanning calorimeter(DSC) and X-ray diffraction(XRD).The crystallization processes of different samples were simulated by JMA equation.Experimental results demonstrated that incubation and crystallization time increased with decreasing isothermal temperature for the same sample.The crystallization mechanism of CeAlFeCo BMGs was discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11032011 and 10872202)the Guangdong Provincial Science and Technology Program(Grant No.2010B050300008)+2 种基金the Guangzhou Municipal Science and Technology Program(Grant No.12F582080022)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(Grant No.x2clB7120290)the Fundamental Research Funds for the Central Universities(Grant Nos.2012ZZ0013 and 2014ZZ0005)
文摘FesoMn15-xCoxNi35 （x=0, 1, 3, 5, 7） alloys were prepared by arc melting under purified argon atmosphere. The ingots were homogenized at 930℃ for 90 h followed by water quenching. The crystal structure, magnetic properties and magnetocaloric effects of the alloys were studied by X-ray diffraction （XRD） and MPMS-7-type SQUID. The results show that all samples still maintained a single γ-（Fe, Ni）-type phase structure. With the increase of the content of Co, the Curie temperatures of these alloys increased and exhibited a second-order magnetic transition from ferromagnetic （FM） to paramagnetic （PM） state near Curie temperature. The maximum magnetic entropy change and the relative cooling power of Fe50Mn10CosNi35 alloy was 2.55 J/kg.K and 181 J/kg, respectively, for an external field change of 5 T. Compared with rare earth metal Gd, FesoMnls-xCoxNi35 series of alloys have obvious advantage in resource price; their Curie temperatures can be tuned to near room temperature, maintain a relatively large magnetic entropy change at the same time and they are a type of potential magnetic refrigeration materials near room temperature.
