共查询到19条相似文献,搜索用时 93 毫秒
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以传统氧化物法合成的Mn-Zn铁氧体前驱体和外购前驱体为实验原料,经压制成形后用频率为2.45 GHz的微波在1 200~1 400℃烧结制备Mn-Zn铁氧体软磁材料.对烧结过程样品的微观结构和形貌进行了研究,并探究了烧结过程致密化特性及微波加热温度对Mn-Zn铁氧体密度的影响.研究表明:微波烧结的Mn-Zn铁氧体具有典型的尖晶石结构,样品主体相为Mn0.4Zn0.6Fe2O4;用SEM观察样品形貌,发现在1 350~1 400℃烧结的样品结晶状况良好,晶界平直,烧结组织均匀;微波烧结温度对密度有较大影响,在1 200~1 400℃,随着烧结温度升高样品密度增高,密度为4.80~5.28 g/cm3,在1 400℃烧结样品比较致密.微波烧结可以实现样品的快速致密. 相似文献
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我国Mn-Zn铁氧体的现状及发展前景 总被引:1,自引:0,他引:1
Mn-Zn铁氧体的产量约占软磁铁氧体总产量的70%,是当前软磁材料中最受关注和最为活跃的领域。多年来相关工作者对其生产技术的发展和应用研究倾注了极大的精力,使我国铁氧体产业得到了迅猛发展。 相似文献
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《中国计量学院学报》2016,(3):350-354
采用传统氧化物陶瓷工艺制备了CaO-Bi2O3-MoO3-Nb2O5复合掺杂高磁导率Mn-Zn铁氧体材料,利用扫描电子显微镜(SEM)、B-H测试仪和阻抗分析仪等对材料结构和磁性能进行了表征,研究了不同添加量CaO对高磁导率Mn-Zn铁氧体的微观结构和磁性能的影响.结果表明,添加适量的CaO可以细化晶粒、提高材料的频率特性和品质因数Q,降低材料的损耗;当质量分数CaO=0.030%时,材料具有最佳的综合性能:μi=9 772.22,L200/L10=99.36%,室温PCV=435.14mW/cm3. 相似文献
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Mn—Zn铁氧体的产量占软磁铁氧体总产量的比例已近90%,其在国民经济与现代科技领域中的作用不言而喻。近年来由于铁矿石与有色金属的涨价风,造成了Mn-Zn铁氧体原材料价格连锁上涨,但是由于种种原因,Mn-Zn铁氧体制品的价格却难以上涨,这给Mn—Zn铁氧体制造商的生产与经营带来很大的压力。 相似文献
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抗电磁干扰Mn-Zn铁氧体的应用及发展 总被引:1,自引:0,他引:1
电磁干扰(EMI)随着电子设备的高速发展成为越来越突出的问题,电子市场已经出台相应的电磁兼容(EMC)市场准入认证.今后的电子元器件及电子设备必须符合相应的市场准入认证.所以,Mn-Zn铁氧体作为电子行业的重要基础材料之一,必须加强抗EMI性能的研究.由于其本身具有吸收和衰减电波的电磁能量性质,成为民用和军事方面抗EMI的重要研究和应用材料.论述了抗EMI Mn-Zn铁氧体材料的主要性能指标,目前国内外已有的该类材料的主要种类,以及相关磁芯的种类及其应用领域.提出今后可能的主要研究或发展方向的见解,认为抗EMI Mn-Zn铁氧体材料和元器件应成为我国目前的重点发展方向. 相似文献
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The interface reactions between SiO2-PbO-MO melts (M = Fe, Mn, Zn and Ni) and Mn-Zn and Ni-Zn ferrites were studied using electron probe microanalysis and X-ray diffraction. Ni ions in the glass melt containing NiO were localized at the interface between the glass and Mn-Zn ferrite. The Ni-rich layer was also detected at the interface between NiO containing glass melt and Ni-Zn ferrite; the composition of this layer was thought to be close to NiFe2O4. Pb8NiSi6O21 crystal was deposited as the product of the reaction with the glass melt and Mn-Zn ferrite at 700 °C. As compared with Mn-Zn ferrite, no reaction products were formed in Ni-Zn ferrite at various temperatures. The dissolution length of Mn-Zn ferrite in SPN5 glass melt was found to be smaller than for other melts, and it is concluded that the NiO-rich layer at the surface of the ferrite is chemically very durable to the glass melts. 相似文献
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雷达吸波包装膜的研究初探 总被引:1,自引:1,他引:0
采用2种不同的铁氧体(复合铁酸锌锰及复合铁酸镍锰)与线性低密度聚乙烯(LLDPE)共混制备了雷达吸波包装膜,分别对热压工艺、介电性能、透湿性能及力学性能进行了研究,结果发现粉末状的LLDPE与铁氧体的混合效果优于颗粒状的LLDPE,铁氧体的加入能明显提高LLDPE的介电损耗,但会使LLDPE的透湿率变大,力学性能变差.当复合铁酸锌锰/复合铁酸镍锰的重量比为45/55,且总含量为30%(质量分数)时,制备出的LLDPE膜具有最佳的隐身及综合力学性能. 相似文献
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Ruifeng Huang Daming Zhang 《IEEE transactions on magnetics》2007,43(10):3807-3815
Analysis of the principle of the published lumped circuit methods for determination of the intrinsic complex permeability and permittivity of the Mn-Zn ferrites reveals that as long as the electric and the magnetic field distributions in the core(s) in two measurements are different, the two intrinsic values can be determined. Using this principle, we developed a set of general lumped circuit methods based on a toroidal Mn-Zn ferrite core as the measurement sample. We examined two possible different excitation modes: magnetic field excitation and electric field excitation. The two different excitation modes result in significantly different field distributions in the sample. Thus, high accuracy can be guaranteed in principle. For the magnetic field excitation, we present in this paper a general finite-difference method to solve the fields in the core and the impedance of the ferrite core inductor. To avoid the stray capacitance among the coils of the ferrite core winding inductor in the measurement, we made a set of short-ended coaxial test fixtures. We performed experiments to determine the intrinsic complex permeability and permittivity of a Mn-Zn ferrite core up to 10 MHz by using the two general methods and validated the measured intrinsic values experimentally. 相似文献
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Ruifeng Huang Daming Zhang 《IEEE transactions on magnetics》2007,43(3):974-981
After setting up a mathematical model for rectangular-shaped Mn-Zn ferrite capacitors, this paper investigates dimensional effects on the intrinsic complex permittivity and the measured apparent complex permittivity of Mn-Zn ferrite blocks. The simple block structure of the samples guarantees their easy and precise preparation. Above a few hundred kilohertz, dimensional effects make the measured apparent complex permittivity deviate from its intrinsic value. This paper uses a Newton-Raphson based method to trace the intrinsic complex permittivity and permeability from the measured impedances of two rectangular-shaped Mn-Zn ferrite capacitors in the frequency range from a few hundred kilohertz to 40 MHz. From the traced intrinsic complex permittivity and permeability, the apparent complex permittivity of a third sample with different dimensions is then calculated theoretically. The papers also presents results of experiments carried out to measure the apparent complex permittivity of the third sample; agreement between the measured and the calculated values is very good. This justifies the validity of the method presented in this paper, when used to determine the dimension-independent intrinsic complex permittivity and permeability of Mn-Zn ferrites 相似文献
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P. A. Atanasov M. E. Koleva R. I. Tomov V. I. Krastev 《Journal of Materials Science: Materials in Electronics》1999,10(4):295-298
Mn-Zn ferrite thin films were deposited on sapphire substrates by pulsed laser deposition from sintered Mn1 – xZn
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Fe2O4 ceramic targets. A full stoichiometric transfer from targets to substrates was achieved. Magnetic inplane measurements in two perpendicular directions were carried out and the macromagnetic properties of films were determined. The hysteresis loops obtained are rectangular and the values of the coercive force, the saturation, and the remanent magnetization are comparable to the same parameters of the bulk Mn-Zn ferrite. The films were characterized using a vibrating sample magnetometer (VSM), a scanning electron microscope (SEM) and by X-ray photoelectron spectroscopy (XPS). 相似文献
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Daming Zhang Chek Fok Foo 《IEEE transactions on magnetics》2005,41(4):1226-1232
Mn-Zn ferrite cores present high permeability within the kilohertz-to-megahertz frequency range. They also present high permittivities within the same frequency range. High permeabilities lead to significant permittivity measurement errors when the conventional two-parallel-electrode method is used. In contrast, high permittivities result in the deviations of measured permeabilities from their intrinsic values. This paper presents a field-circuit coupled method to study each of these two phenomena by examining a ferrite toroid with rectangular cross section. The same toroid is used to construct an inductor and a capacitor, respectively. Analytical expressions for electric and magnetic fields in, and complex power supplied to the inductor and capacitor are formulated. Results are obtained, which show that the measured permeabilities and permittivities for Mn-Zn ferrites deviate from their intrinsic values significantly. A Newton-Raphson method is then introduced to determine the intrinsic permeabilities and permittivities based on their measured values. 相似文献
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Hot-pressed ferrites have been studied in connection with fabrication of a high quality head material. A two-step hot-pressing technique has enabled the preparation of hot-pressed ferrite with a porosity lower than 0.1 percent and an adjusted average grain size between 0.1 μm and 500 μm. The largest available ingot of hot-pressed ferrite is 120 mm in diameter and 20 mm in thickness. A hot-pressed Mn-Zn ferrite with an adjusted microstructure can be made with a μm of 40 000 and an Hc lower than 0.02 Oe. A hot-pressed Mn-Zn ferrite of another composition will have a Bm greater than 5000 G and a μ0 of 700 at 10 MHz. The effect of mechanical working on magnetic properties of hot-pressed ferrites, single-crystal ferrites, and high-density ferrites is also described. The lapping characteristics and the wear problems in a ferrite head of hot-pressed, single-crystal, and high-density ferrite are also discussed. 相似文献
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Characteristics of powder and sintered bodies of hydrothermally synthesized Mn-Zn ferrites 总被引:1,自引:0,他引:1
To improve the sinterability of powders fabricated by the conventional mixed-oxides method, ultrafine Mn-Zn ferrite powders were hydrothermally synthesized from metal nitrates solution using ammonia as a precipitant. The R value (alkalinity) was introduced to adjust the amount of added OH– in the reaction suspension. The characteristics of the powders synthesized at different hydrothermal conditions and the properties of the sintered bodies were investigated. The results show that the R value and hydrothermal time have a great effect on the compositions and phases of hydrothermally synthesized Mn-Zn ferrite powders. Powders synthesized from a starting suspension with a higher content of Zn ions (or lower content of Mn2+) may approach to a stable spinel structure with a lower Mn/Zn ratio as the hydrothermal time is longer. Factors affecting the position of the diffraction angle (2) of the spinel Mn-Zn ferrite (311) of powders may include both the compositions of spinel ferrite structure and crystallite sizes (or particle sizes) of powders. Some possible reasons were suggested to explain the dependence of composition and phase of hydrothermally synthesized Mn-Zn ferrite powders on the R value and hydrothermal time. The temperature that the green compact begins to shrink at increases with increasing R value, and ranges from 510°C (R = 2) to 650°C (R = 6). After being sintered at 950°C for 2 h in N2 atmosphere, the relative sintered density of each specimen reaches a value of 94.5–99.8%. 相似文献