In order to obtain high comprehensive performance hollow ceramic microspheres (HCMs), used Al-Cr2O3 as the main reaction system, HCMs were prepared by Self-reactive flame quenching technology in Ar2 and N2 atmosphere ...In order to obtain high comprehensive performance hollow ceramic microspheres (HCMs), used Al-Cr2O3 as the main reaction system, HCMs were prepared by Self-reactive flame quenching technology in Ar2 and N2 atmosphere respectively. Effects of the two different atmospheres on synthesizing HCMs were studied. Results show that in Ar2 atmosphere, because of incomplete reaction of agglomerate powders, porous particles with hollow structure and smooth-faced HCMs constitute the products. However in N2 atmosphere, because agglomerate powders react completely, all of them become smooth-faced HCMs. Results above show that experiment atmosphere is a important parameter to synthesize HCMs and to a great extent influences reaction process of agglomerate powders in the flame field.展开更多
利用自反应淬熄法制备了Zn-Ti钡铁氧体空心陶瓷微珠吸波材料,这种材料具有核/壳结构,比一般的铁氧体密度小,是一种新型的吸波材料;通过SEM、EDS和XRD分析表明,该材料具有中空结构,成球规则,粒径分布均匀,经过热处理之后,由非晶相物质转...利用自反应淬熄法制备了Zn-Ti钡铁氧体空心陶瓷微珠吸波材料,这种材料具有核/壳结构,比一般的铁氧体密度小,是一种新型的吸波材料;通过SEM、EDS和XRD分析表明,该材料具有中空结构,成球规则,粒径分布均匀,经过热处理之后,由非晶相物质转变为了晶相物质,主要物相为Ba Zn Ti Fe10O19和Ba Fe12O19;通过吸波性能测试,该材料具有一定的吸波性能,经过热处理之后吸波性能提高了,其吸波最低反射率为–21.98 d B,反射率小于–10 d B的带宽大于2 GH Z。展开更多
NaCl aqueous solution（15 wt%） was used as the quenching medium to prepare amorphous Lithium-Zinc ferrite hollow microspheres（LiZn FHMs） based on self-reactive quenching technology. Investigations by scanning elect...NaCl aqueous solution（15 wt%） was used as the quenching medium to prepare amorphous Lithium-Zinc ferrite hollow microspheres（LiZn FHMs） based on self-reactive quenching technology. Investigations by scanning electro microscope, X-ray diffraction, electron diffraction of transmission electron microscope, and differential scanning calorimetry prove that LiZn FHMs are susceptible to amorphization. It is indicated that NaCl aqueous solution（15 wt%） has ultra-fast quenching speed, and the growth rate of crystals on LiZn FHMs is so large that the formation and growth of the crystal nucleus are significantly restrained. This is the main reason for the formation of amorphous LiZn FHMs.展开更多
A1 ＋ BaO2 ＋ Fe2O3 ＋ sucrose and O2 as reaction system and feeding gas, respectively, are used to prepare hollow multiphase ceramic microspheres （HMCMs） absorbent based on self-reactive quenching technology. The m...A1 ＋ BaO2 ＋ Fe2O3 ＋ sucrose and O2 as reaction system and feeding gas, respectively, are used to prepare hollow multiphase ceramic microspheres （HMCMs） absorbent based on self-reactive quenching technology. The morphologies, particle size distribution, hollow structure and phase compositions were characterized by scanning electron microscope （SEM）, X-ray diffraction （XRD） and size analysis. The results show that the quenching products possess high sphere-forming rate, and most of them are hollow structures. Owing to the self-burst, the particle size is between 40 and 70 μm. The phase compositions contain Al2O3, Fe3O4, Fe2O3, Ba2Fe14O22, BaO2 and BaFe4O7. The microwave absorbing tests show that the lowest reflectivity of HMCMs is -19 dB. The frequency bands less than -10 dB are from 13.0 to 15.8 GHz. The reasons for HMCMs possessing good microwave absorbing properties may be their magnetic and electrical properties as well as special hollow structure.展开更多
Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching met...Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching method which is integrated with flame jet,selfpropagating high-temperature synthesis(SHS),and rapidly solidification.The morphologies and phase compositions of hollow microspheres were studied by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),and energy dispersive spectroscopy.The results show that the quenching products are regular spherical substantially with hollow structure,particle size is between few hundreds nanometers and 5 lm.Phase compositions are diphase of Fe3O4,Mn3O4,and MnFe2O4,and the spinel soft magnetic ferrite MnFe2O4 with microwave magnetic properties is in majority.Collisions with each other,burst as well as‘‘refinement’’of agglomerate powders in flame field may be the main reasons for the formation of micro-nano hollow multiphase ceramic microspheres containing MnFeOabsorbent.展开更多
基金National Nature Science Foundation of China (50672130)
文摘In order to obtain high comprehensive performance hollow ceramic microspheres (HCMs), used Al-Cr2O3 as the main reaction system, HCMs were prepared by Self-reactive flame quenching technology in Ar2 and N2 atmosphere respectively. Effects of the two different atmospheres on synthesizing HCMs were studied. Results show that in Ar2 atmosphere, because of incomplete reaction of agglomerate powders, porous particles with hollow structure and smooth-faced HCMs constitute the products. However in N2 atmosphere, because agglomerate powders react completely, all of them become smooth-faced HCMs. Results above show that experiment atmosphere is a important parameter to synthesize HCMs and to a great extent influences reaction process of agglomerate powders in the flame field.
文摘利用自反应淬熄法制备了Zn-Ti钡铁氧体空心陶瓷微珠吸波材料,这种材料具有核/壳结构,比一般的铁氧体密度小,是一种新型的吸波材料;通过SEM、EDS和XRD分析表明,该材料具有中空结构,成球规则,粒径分布均匀,经过热处理之后,由非晶相物质转变为了晶相物质,主要物相为Ba Zn Ti Fe10O19和Ba Fe12O19;通过吸波性能测试,该材料具有一定的吸波性能,经过热处理之后吸波性能提高了,其吸波最低反射率为–21.98 d B,反射率小于–10 d B的带宽大于2 GH Z。
基金Funded by the National Natural Science Foundation of China(No.51172282)the Hebei Natural Science Foundation of China(E2015506011)
文摘NaCl aqueous solution（15 wt%） was used as the quenching medium to prepare amorphous Lithium-Zinc ferrite hollow microspheres（LiZn FHMs） based on self-reactive quenching technology. Investigations by scanning electro microscope, X-ray diffraction, electron diffraction of transmission electron microscope, and differential scanning calorimetry prove that LiZn FHMs are susceptible to amorphization. It is indicated that NaCl aqueous solution（15 wt%） has ultra-fast quenching speed, and the growth rate of crystals on LiZn FHMs is so large that the formation and growth of the crystal nucleus are significantly restrained. This is the main reason for the formation of amorphous LiZn FHMs.
基金financially supported by the National Natural Science Foundation of China(No.51172282)
文摘A1 ＋ BaO2 ＋ Fe2O3 ＋ sucrose and O2 as reaction system and feeding gas, respectively, are used to prepare hollow multiphase ceramic microspheres （HMCMs） absorbent based on self-reactive quenching technology. The morphologies, particle size distribution, hollow structure and phase compositions were characterized by scanning electron microscope （SEM）, X-ray diffraction （XRD） and size analysis. The results show that the quenching products possess high sphere-forming rate, and most of them are hollow structures. Owing to the self-burst, the particle size is between 40 and 70 μm. The phase compositions contain Al2O3, Fe3O4, Fe2O3, Ba2Fe14O22, BaO2 and BaFe4O7. The microwave absorbing tests show that the lowest reflectivity of HMCMs is -19 dB. The frequency bands less than -10 dB are from 13.0 to 15.8 GHz. The reasons for HMCMs possessing good microwave absorbing properties may be their magnetic and electrical properties as well as special hollow structure.
基金supported by the ational Natural Science Foundation of China (No. 51172282)
文摘Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching method which is integrated with flame jet,selfpropagating high-temperature synthesis(SHS),and rapidly solidification.The morphologies and phase compositions of hollow microspheres were studied by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),and energy dispersive spectroscopy.The results show that the quenching products are regular spherical substantially with hollow structure,particle size is between few hundreds nanometers and 5 lm.Phase compositions are diphase of Fe3O4,Mn3O4,and MnFe2O4,and the spinel soft magnetic ferrite MnFe2O4 with microwave magnetic properties is in majority.Collisions with each other,burst as well as‘‘refinement’’of agglomerate powders in flame field may be the main reasons for the formation of micro-nano hollow multiphase ceramic microspheres containing MnFeOabsorbent.
