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Ni_(1-x)Co_xFe_2O_4铁氧体纳米粉末的磁性能和微波吸收特性 总被引:1,自引:0,他引:1
利用柠檬酸溶胶-凝胶自蔓延燃烧法合成了Ni1-xCoxFe2O4(x=0,0.1,0.3,0.5)铁氧体纳米粉末。利用XRD、VSM和矢量网络分析仪测定了粉末样品的晶体结构、磁性能和电磁参数。定性分析了样品的饱和磁化强度、矫顽力、复磁导率和复介电常数随频率和Co含量的变化关系。结果表明,自蔓延的所有粉末样品经过600℃,2h高温退火后均为尖晶石相纳米晶颗粒。随着Co替代量x的增加,样品的自然共振频率先增大后减小,并对微波吸收特性有一定的改善。 相似文献
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采用溶胶-凝胶法制备了(1-x) BaFe12O19/xBaTiO3复合吸波材料(x=0、0.1、0.3、0.5、0.7、0.9、1).研究了钛酸钡含量对复合样品晶体结构、微观形貌以及微波性能的影响.结果表明,于900℃煅烧的样品形成了BaFe12O19相和BaTiO3相共存的BaFe12O19/BaTiO3复合体系;当钛酸钡含量在0.3~0.7时,复合样品的介电损耗和磁损耗显著增强,提高了微波吸收性能,拓宽了有效吸收频带;当厚度为3mm时,x=0.5的复合样品在频率为13GHz处的最强吸收峰为14.8dB,x=0.7的复合样品的有效吸收频宽可达3.4GHz. 相似文献
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用溶胶-凝胶法制备BiFe1-x Cox O3样品,用X射线衍射仪、扫描电镜、能谱分析对样品的结构、微观形貌、元素组成进行了表征,用微波矢量网络分析仪测试了样品在2~18GHz微波频率范围的复介电常数、复磁导率,并计算了损耗角正切及微波反射率。结果表明,当掺杂量x=0、x=0.1、x=0.2,煅烧温度800℃时,产物的主相为钙钛矿型BiFeO3,同时还有杂相Bi25FeO40,颗粒形貌为尺寸约1.5μm的立方形;Co的掺入有利于提高体系的微波吸收性能。当样品厚度为1.8mm,x=0.2时,吸收峰值为-26.5dB,带宽为2.08GHz,在高频段有良好的微波吸收,材料兼具介电损耗和磁损耗但介电损耗相对较强。 相似文献
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用溶胶-凝胶法制备锰锌掺杂Z型钡钴铁氧体Ba3(MnZn)xCo2(1-x)Fe24O41(x=0.0、0.1、0.2、0.3、0.4、0.5)样品。用XRD和SEM对样品的晶体结构、颗粒形貌进行表征,用微波矢量网络分析仪测试该样品在2~18GHz微波频率范围的复介电常数、复磁导率,根据测量数据计算电磁损耗角正切及反射率,探讨该材料的微波吸收性能与电磁损耗机理。结果表明样品为Z型六角铁氧体晶体结构,颗粒呈六角片状形貌;当样品厚度为2.2mm、x=0.4时,在频率3.9GHz处吸收峰值为38.5dB,10dB以上频带宽度为3.8GHz;该材料能在1~5.8GHz微波低频范围实现有效吸收,其微波吸收兼具磁损耗和介电损耗,但磁损耗更为显著。 相似文献
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采用溶胶-凝胶法制备了掺杂稀土元素镧的钡铁氧体超微粉末,就镧元素的掺杂含量对钡铁氧体吸波性能的影响进行了对比研究.实验表明,用聚乙二醇凝胶法制备的BaLaxFe12-xO19超微粉末,当x为0.03时,对微波吸收效果最佳.在涂层厚度1.0mm,测试频段为7.5~11.9GHz内,吸收量均在25dB以上,在11.6GHz处,吸收峰值达41.4dB. 相似文献
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采用固相反应法合成了中温固体氧化物燃料电池阴极材料Ln0.6Sr0.4Fe1-χCoχO3-σ(Ln=La,Pr;Nd,Sm和Gd)粉体.对其进行结晶学表征,分析氧含量和失重与温度的关系,并研究了其电导率随温度的变化规律及其与Ce0.8Gd0.2O1.9(CGO)电解质的化学相容性.实验表明,600~800℃;所有样品的电导率均高于100S/cm,其中Nd0.6Sr0.4Co0.8Fe0.2O3-σ的电导率高达600S/cm,并且与CGO电解质都具有良好的化学相容性. 相似文献
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用柠檬酸(C6H8O7)为络合剂,以硝酸钐(Sm(NO3)3)、钛酸四丁酯(C16H36O4Ti)、硝酸钡(Ba(NO3)2)为原料,采用溶胶-凝胶法制备单相Ba3.99Sm9.34Ti18O54微波介质陶瓷粉体。采用差热分析、X射线衍射表征Ba3.99Sm9.34Ti18O54前驱体的热行为和晶型转化过程,用场发射扫描电镜对粉体的形貌进行表征。结果表明:在1000℃下保温3h可以获得纯Ba3.99Sm9.34Ti18O54陶瓷粉体,形状为不规则片状,平均粒径为100~200nm。 相似文献
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本文采用缺铁配方BaZnxCo2-xFe15.5O27制备W型六角铁氧体,并深入研究了不同Zn离子和Co离子含量对铁氧体复合物微波性能的影响。结果表明,缺铁配方六角铁氧体复合物拥有较低的介电常数,控制Zn离子Co离子可以有效调控铁氧体复合物介电常数以及共振频率。同时通过在铁氧体复合物中添加纳米碳管调控复合物介电常数,证明纳米碳管添加量在一定范围内,铁氧体复合物可以获得优秀的微波吸收性能。 相似文献
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Sr0.95Ca0.05Fe12O19六角铁氧体的微波特性 总被引:2,自引:0,他引:2
采用标准陶瓷工艺,并进行湿压磁场成型和氧气氛烧结,制备了目前尚未见报道的高取向度,低介电损耗的各向异性Sr0.95Ca0.05Fe12O19多晶六角铁氧体。研究了它们的比饱和磁化强度(δs),磁晶各向异性场(H^A)同温度(T)的变化关系,并对其取向度进行了较深入的讨论。 相似文献
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E. D. Solov’eva E. V. Pashkova A. E. Perekos B. S. Khomenko A. G. Belous 《Inorganic Materials》2013,49(6):621-625
We have studied the effect of “double” substitution in Ba0.7Sr0.3Fe12 ? 2x Co x Ti x O19 on the structural and magnetic properties of M-type barium hexaferrite. The basic composition of Ba1 ? x Sr x Fe12O19 obtained by heat-treating carbonate-hydroxide precipitates has been optimized (x = 0.3). 2Fe3+ → Co2+ + Ti4+ substitutions considerably reduce the coercive force (H c) and increase the magnetization (M s) relative to Ba0.7Sr0.3Fe12 O19. 相似文献
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Ali Sharbati Javad Mola Verdi Khani 《Journal of Materials Science: Materials in Electronics》2013,24(10):3629-3633
Sr1?x Ho x (ZnZr)0.5Fe11O19 (x = 0.03, 0.06 and 0.09) hexaferrite nanocrystallites of average sizes in the range of 46–60 nm are synthesized by the citrate sol–gel method. Crystalline structure, morphology, magnetic properties, and microwave absorption properties of powders were studied via X-ray diffraction, field emission scanning electron microscope vibrating sample magnetometer, and vector network analyzer, respectively. The magnetic properties such as saturation magnetization (M s ) and coercivity (H c ) were calculated from hysteresis loops. The XRD patterns show that the main phase is M-type strontium hexaferrite without other impurity phases. Microwave absorption properties of hexaferrite (70 wt%)–acrylic resin (30 wt%) composites were measured by the standing-wave-ratio (SWR) method in the range from 12 to 20 GHz. Results showed that substitution of Ho3+ ions for Sr2+ ions in Sr(ZnZr)0.5Fe11O19 resonance frequency moves to higher frequency. For samples with x = 0.03, a minimum reflection loss of ?42 dB was obtained at 16.6 GHz for a layer of 1.7 mm in thickness. It was concluded that the prepared composites could be good candidates for electromagnetic compatibility and other practical applications at high frequency. 相似文献
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Aibo Zhang Meng Tang Xiufen Cao Zhengbin Lu Yongtao Shen 《Journal of Materials Science》2014,49(13):4629-4635
The hybrid microwave absorber of Fe3O4/multi-walled carbon nanotubes (MWNTs)modified with polyethylenimine (PEI) polymers was fabricated by chemical co-precipitation. The structure and morphology of hybrids are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron-microscopy (TEM). The effect of PEI on the distribution of Fe3O4 nanoparticles and the microwave absorbing properties of hybrid microwave absorber of Fe3O4/MWNTs were investigated. The TEM results show that Fe3O4 nanoparticles are attached homogeneously on MWNTs, which indicates that the adding of PEI is effective to control the distribution of Fe3O4 nanoparticles on the surface of MWNTs. The microwave absorbing properties results show that the maximum reflection loss (RL) of PEI modified Fe3O4/MWNTs hybrids is improved significantly, which is ?30.69 dB at 7.24 GHz and ?10 dB bandwidth is 1.84 GHz. However, the RL of the Fe3O4/MWNTs without PEI is ?21.96 dB at 7.02 GHz and ?10 dB bandwidth is 1.2 GHz. 相似文献
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以马尾松边材为模板,用sol-gel法制备出多层壁结构Sr1-xLaxFe12-xCoxO19(x=0~0.2)铁氧体样品。利用XRD、SEM、VSM对样品的结构、形貌、磁性进行了表征。结果表明锶铁氧体保留了木材的多层壁结构,壁厚约1~2μm,锶铁氧体微粒尺寸约在1~1.5μm,每个微粒水平连接构成管胞壁。样品的饱和磁化强度随x值增大而增加,矫顽力则随着x值增大先增大后减小。但平行壁方向(A方向)的矫顽力明显低于其它方向(B、C方向)。 相似文献
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A. N. Tarale S. R. Jigajeni D. J. Salunkhe P. B. Joshi S. B. Kulkarni D. M. Phase R. J. Chaudhary S. K. Deshapande 《Journal of Materials Science: Materials in Electronics》2012,23(2):557-566
The paper presents synthesis of Ba0.7Sr0.3TiO3 (BST), Ba0.7Sr0.3TiO3 (BZT) thin films and BZT/BST heterostructures using modified Pechini method. The La0.7Sr0.3MnO3 has been used as a conducting bottom layer to form metal ferroelectric metal capacitor. The thin films are spin coated on
SiO2/n-Si (100) substrates. The thin films thus deposited are characterized for crystal structure, morphology, dielectric and
complex impedance properties. The results show that BZT/BST heterostructures show reduced loss tangent tan δ and useful value
of figure of merit γ in RF range of frequencies. The results on dielectric properties could be analyzed in terms of the Maxwell–Wagner
Model and contribution due to superlattice effects. 相似文献