Papers by Keyword: Magnetic Fly-Ash Hollow Cenosphere

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Authors: Ru Xin Che, Chun Xia Wang, Bing Yu
Abstract: The core-nanoshell composite materials doped with Nd were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Nd. The thermal decomposition process of the sample was investigated by TG- DTA. The morphology and composition of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The results of vibrating sample magnetometer ( VSM ) analysis indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating. The exchange-coupling interaction enhances magnetic loss of composite materials. The results show that doped with Nd can enhance the coercivity too, so the magnetic properties could be promoted further. The magnetic properties of the core-nanoshell composite material are better than that of single-phase.
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Authors: Ru Xin Che, Bing Yu, Chun Xia Wang
Abstract: The core-nanoshell composite materials doped with Sm were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Sm. The thermal decomposition process of the sample was investigated by thermogravimetric analysis-differential scanning calorimetry ( TG- DSC ). The morphology and composition of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The results of vibrating sample magnetometer analysis ( VSM ) indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating, which caused outstanding magnetic properties. The results show that doped with Sm can enhance the coercivity too, so the magnetic properties could be promoted further by the adjustment of compositions and the use of special techniques. The magnetic properties of the core-nanoshell composite material are better than that of single-phase.
461
Authors: Ru Xin Che, Bing Yu, Li Qiu Wei
Abstract: The core-nanoshell composite materials doped with Nd were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Nd. The thermal decomposition process of the sample was carried out by the thermogravimetry and differential thermal analysis ( TG-DTA ). The morphology and components of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The microwave absorption property was investigated by vector network analyzer ( VNA ). The results indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating. The exchange-coupling interaction enhances magnetic loss of composite materials. So, in the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the core-nanoshell composite absorbers can achieve –31 dB, it is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption.
36
Authors: Ru Xin Che, Bing Yu, Chun Xia Wang, Li Qiu Wei
Abstract: The core-nanoshell composite materials doped with Sm were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Sm. The thermal decomposition process of the sample was investigated by thermogravimetric analysis-differential scanning calorimetry ( TG- DSC ). The morphology and components of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The microwave absorption property was investigated by vector network analyzer ( VNA ). The results indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating. The exchange-coupling interaction enhances magnetic loss of composite materials. So, in the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the core-nanoshell composite absorbers can achieve –32 dB, it is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption.
514
Authors: Xiao Na He, Ru Xin Che, Yi Lin Wang, Yue Li, Li Peng Wan
Abstract: The core-nanoshell composite materials with magnetic fly-ash hollow cenosphere as core and nanoLaFeO3 as shell were synthesized by high-energy ball milling method. The samples were characterized by XRD, SEM and VSM. The results show that the core-nanoshell composite materials were prepared successfully. As the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating,the remanence and the coercivity improves, so it is better for core-nanoshell to adsorb heavy metals. The adsorption-magnetic separation processing were used for Cr (VI) of heavy metals in water, by atomic absorption spectrometry to measure ion concentration after adsorption. Batch experiments were carried out to investigate the effect of solution pH on the adsorption as well as adsorption kinetics and adsorption isotherm. The results show that at pH 2, obtain the maximum removal rate. The adsorption data were better fitted for the Freundlich model,indicating that the adsorption of Cr (VI) preferably follows multilayer and heterogeneous adsorption process. Compared with two kinetic models linear fitting parameters, adsorption conforms to pseudo secend-order kinetic model well,revealing chemisorption as the dominant mechanism.
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