通过在氩气中碳化含有乙酰丙酮金属盐的电纺聚丙烯腈纳米纤维合成了镶嵌(Fe1-xCox)0.8Ni0.2(x=0.25,0.50,0.75)合金纳米粒子的碳纳米纤维,用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、振动样品磁强计(VSM)和矢量网络分析仪(VNA)...通过在氩气中碳化含有乙酰丙酮金属盐的电纺聚丙烯腈纳米纤维合成了镶嵌(Fe1-xCox)0.8Ni0.2(x=0.25,0.50,0.75)合金纳米粒子的碳纳米纤维,用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、振动样品磁强计(VSM)和矢量网络分析仪(VNA)等对其物相、形貌、微观结构、静磁及电磁特性进行表征和分析,并根据传输线理论模拟计算了2~18 GHz频率范围内的微波吸收性能。结果表明:所制备的复合纳米纤维具有典型的铁磁特征,由无定形碳、石墨和面心立方结构Fe-Co-Ni合金三相组成,原位形成的合金纳米粒子沿纤维轴向均匀分布,且被有序石墨层所包覆。磁损耗和介电损耗间的协同作用及特殊的核/壳微观结构使仅含5%(w/w)的(Fe1-xCox)0.8Ni0.2/C复合纳米纤维的硅胶基吸波涂层表现出优异的微波吸收性能。当涂层厚度为1.1~5.0 mm时,x=0.25、0.50和0.75的样品最小反射损耗分别达到-78.5、-80.2和-63.4 d B,反射损耗在-20 d B以下的吸收带宽分别为14.9、14.8和14.5 GHz,几乎覆盖整个S波段至Ku波段。通过调节合金的组成可对材料的电磁特性及微波吸收性能进行一定程度的控制。展开更多
With the copper/iron cinder as the starting material,ferrous ions were obtained through maturing,acid leaching,reducing and purifying processes,and then iron nanoparticles were prepared by reacting with sodium borohyd...With the copper/iron cinder as the starting material,ferrous ions were obtained through maturing,acid leaching,reducing and purifying processes,and then iron nanoparticles were prepared by reacting with sodium borohydride in the system of ethanol-water.The nano Fe/SiO2 core-shell composite particles were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS).The products were characterized by X-ray diffraction (XRD),transmission electron microscope (TEM) and reflectance absorption infrared spectroscopy (RA-IR).The particles were randomly dispersed in paraffin at a mass ratio of 5.5∶4.5 for microwave electromagnetic parameters detection in the frequency range of 2.0—18.0 GHz by vector network analyzer.The results showed that there were two characteristic absorption peaks of Si—O and Si—O—Fe bond appearing at 1389 cm-1 and 878 cm-1,which indicated that the nano iron was successfully coated by SiO2.Through measuring and calculation,the minimal reflection loss was-39.0 dB at 17.2 GHz when the sample thickness was 4.5 mm.So nano Fe/SiO2 core-shell composite particles can be prepared from copper/iron cider to be used as an effective microwave absorbing material.展开更多
文摘通过在氩气中碳化含有乙酰丙酮金属盐的电纺聚丙烯腈纳米纤维合成了镶嵌(Fe1-xCox)0.8Ni0.2(x=0.25,0.50,0.75)合金纳米粒子的碳纳米纤维,用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、振动样品磁强计(VSM)和矢量网络分析仪(VNA)等对其物相、形貌、微观结构、静磁及电磁特性进行表征和分析,并根据传输线理论模拟计算了2~18 GHz频率范围内的微波吸收性能。结果表明:所制备的复合纳米纤维具有典型的铁磁特征,由无定形碳、石墨和面心立方结构Fe-Co-Ni合金三相组成,原位形成的合金纳米粒子沿纤维轴向均匀分布,且被有序石墨层所包覆。磁损耗和介电损耗间的协同作用及特殊的核/壳微观结构使仅含5%(w/w)的(Fe1-xCox)0.8Ni0.2/C复合纳米纤维的硅胶基吸波涂层表现出优异的微波吸收性能。当涂层厚度为1.1~5.0 mm时,x=0.25、0.50和0.75的样品最小反射损耗分别达到-78.5、-80.2和-63.4 d B,反射损耗在-20 d B以下的吸收带宽分别为14.9、14.8和14.5 GHz,几乎覆盖整个S波段至Ku波段。通过调节合金的组成可对材料的电磁特性及微波吸收性能进行一定程度的控制。
文摘With the copper/iron cinder as the starting material,ferrous ions were obtained through maturing,acid leaching,reducing and purifying processes,and then iron nanoparticles were prepared by reacting with sodium borohydride in the system of ethanol-water.The nano Fe/SiO2 core-shell composite particles were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS).The products were characterized by X-ray diffraction (XRD),transmission electron microscope (TEM) and reflectance absorption infrared spectroscopy (RA-IR).The particles were randomly dispersed in paraffin at a mass ratio of 5.5∶4.5 for microwave electromagnetic parameters detection in the frequency range of 2.0—18.0 GHz by vector network analyzer.The results showed that there were two characteristic absorption peaks of Si—O and Si—O—Fe bond appearing at 1389 cm-1 and 878 cm-1,which indicated that the nano iron was successfully coated by SiO2.Through measuring and calculation,the minimal reflection loss was-39.0 dB at 17.2 GHz when the sample thickness was 4.5 mm.So nano Fe/SiO2 core-shell composite particles can be prepared from copper/iron cider to be used as an effective microwave absorbing material.
