用精铁矿粉和Mn3O4制备功率软磁铁氧体的实验研究

用精铁矿粉代替Fe2O3，用Mn3O4代替MnCo3制备功率软磁MnZn铁氧体的实验研究，得出了最佳配方和烧结温度，事实表明，用精铁矿粉和Mn3O4可以制备出性能优良的软磁MnZn铁氧体。     

用精铁矿粉和Mn3O4制功率软磁MnZn铁氧体的配方和掺杂研究

本文描述了用精铁矿粉和Mn3O4成功制备出功率软磁MnZn铁氧体,研究了配方和掺杂对铁氧体磁性能的影响.     

精矿粉和Mn3O4制备MnZn功率铁氧体工艺研究

为了降低功率铁氧体的制备成本,采用传统氧化物陶瓷工艺,用精铁矿粉代替Fe2O3、用Mn3O4代替MnCO3制备出高性能功率软磁MnZn铁氧体.研究了精铁矿粉和Mn3O4制备MnZn铁氧体的固相反应及预烧温度、烧结温度和掺杂对样品磁性能的影响.实验结果表明:精矿粉经氧化生成的α-Fe2O3立即与Mn3O4反应生成MnZn铁氧体,使固相反应更完全;预烧温度为1100℃,烧结温度为1240～1280 ℃时样品性能最佳;适当的掺杂可降低样品的功耗.样品最佳性能如下:μi=2268;Bs=508 mT;Tc=227℃;Po=34.5 W/kg,综合性能达到日本TDK PC30材料性能水平.     

精矿粉和Mn3O4制备MnZR功率铁氧体工艺研究

为了降低功率铁氧体的制备成本，采用传统氧化物陶瓷工艺，用精铁矿粉代替Fe2O3、用Mn3O4代替MnCO3制备出高性能功率软磁MnZn铁氧体．研究了精铁矿粉和Mn，04制备MnZn铁氧体的固相反应及预烧温度、烧结温度和掺杂对样品磁性能的影响．实验结果表明：精矿粉经氧化生成的α—Fe2O3立即与Mn3O4反应生成MnZn铁氧体，使固相反应更完全；预烧温度为1100℃，烧结温度为1240～1280℃时样品性能最佳；适当的掺杂可降低样品的功耗．样品最佳性能如下：μi=2268；Bs=508mT；Te=227℃；P0：34．5W／kg，综合性能达到日本TDKPC30材料性能水平．     

用精铁矿粉代替铁红制备功率软磁铁氧体的实验研究

用精铁矿粉(Fe3O4)代替铁红(Fe2O3)制备功率软磁铁氧体是一项开拓价廉量富原材料的高技术和高效益应用的创新研究课题.本文介绍了其中因代替原材料的成分不同及含SiO2杂质量较高等引起的氧化物制备工艺中面临新的技术关键和难点所进行的实验研究.结果不仅在实验室中用Fe3O4代替Fe2O3和Mn3O4代替MnCO3研制出功率MnZn铁氧体样品,而且在现有的小型企业生产线上中试生产出合格的功率软磁铁氧体元件产品.     

用精铁矿粉和Mn3O4制备功率铁氧体的工艺研究

作者对配方设计,工艺流程等进行了大量的研究,得到了最佳配方和比较合适的工艺方法.结果表明,能用精铁矿粉和Mn3O4制备出接近于日本PC30性能的功率铁氧体.实验样品的磁性能:Bs为485～530mT,μi为1800～2100,Po为39～45w/kg,Tc为200～240℃.     

用精铁矿粉和Mn3O4制备高Bs铁氧体的探索

本文介绍了用廉价精铁矿粉和Mn3O4制备高Bs铁氧体的工艺探索,并分析了配方和烧结温度对其磁性能的影响,提出了进一步研究的途径.     

用精铁矿粉制备BaZnCoTi-W型微波吸收铁氧体材料

利用称重、磁性探测和XRD图谱相结合的方式,分析了精铁矿粉的氧化相变过程,发现在750℃时,精铁矿粉被氧化生成α-Fe2O3;采用氧化工艺,直接用精铁矿粉和BaCO3一次烧结制备W型钡铁氧体BaZn1-aMnaCo1+0.5xTi0.5xFe16-XO27,分别研究了Co2+Ti 4+含量(x值)和涂层厚度对磁性能的影响,结果表明:当厚度为2.1mm及x=1.25时,样品在x全波段内(8～12GHZ)吸收衰减大于10dB,吸收峰达到31dB。     

用精铁矿粉和Mn3O4制备高Bs铁氧体的探索

本文介绍了用廉价精铁矿粉和Mn3O4制备高Bs铁氧体的工艺探索，并分析了配方和烧结温度对其磁性能的影响，提出了进一步研究的途径。     

微波加热含碳红铁矿粉升温特性研究

本文通过对含碳红铁矿粉进行微波加热磁化焙烧,研究含碳铁矿粉在微波场中的升温特性。研究的因素主要包括粒度、功率、配碳量,分析各个因素对含碳铁矿粉吸收微波能力的影响。     

用精矿粉和Mn3O4制备高性能功率软磁MnZn铁氧体

用精矿粉代替Fe2O3、用Mn3O4代替MnCO3作为原材料，因为减少了Mn离子在反应中的变价机率，提高了配方中Mn离子的准确性，精矿粉的主要成分Fe3O4相变为α-Fe2O3的温度与Mn铁氧体生成温度接近，所以使固相反应更安全，能制备出高性能功率软磁MnZn铁氧体。适量的掺杂CaCO3、V2O5及Bi2O3可以进一步降低样品功耗；制备过程中，采取一些特殊工艺措施及适当烧结温度能进一步提高样品磁性能，使其综合性能基本达到日本TDK的PC30水平。     

Investigating the Characteristics of Cobalt-Substituted MnZn Ferrites by Equivalent Electrical Elements

We investigated the electrical and magnetic properties of cobalt-substituted manganese-zinc soft ferrite by using the equivalent lumped elements acquired from the appropriate equivalent electrical circuit of polycrystalline ferrite. We applied the equivalent lumped circuit, combined with equivalent lumped resistances and capacitance, to determine the effect of microstructure on electrical and magnetic properties of cobalt-substituted manganese-zinc ferrites. Both the hysteresis loss and the eddy-current loss of soft ferrites account for a major proportion of iron loss in high-frequency switching mode power supplies. Replacing a small portion of Fe²⁺ with Co²⁺ remarkably increases the bulk resistivity of the MnZn ferrite and decreases the core loss by lowering eddy-current loss. A longer isothermal duration causes grain growth and forms a larger equivalent capacitance, which leads to a reduction in hysteresis loss. However, excess substitution of Co²⁺ for Fe²⁺ is disadvantageous to magnetic permeability and raises core loss. We measured the dc resistivity by the four-probe method on sintered disks with both sides polished and coated with a thin layer of silver paste as a good contact material. We measured the magnetic permeability by an impedance analyzer at room temperature. The total loss of Mn_0.58Zn_0.37 Co_0.01Fe_2.04O₄ ferrite core does not exceed 420 mW/cm³ at 300 kHz/70 mT.     

High-frequency MnZn soft magnetic ferrite by engineering grain boundaries with multiple-ion doping

MnZn soft magnetic ferrites have been widely utilized in power electronics,owing to the combined merits of high permeability and low energy loss.However,their deployment would result in a drastic increase in power dissipation at ＞3 MHz,thus limiting the scope extent of miniaturization,together with their efficiency.Here,we report a high-performance MnZn ferrite by doping multiple ions (La,Ti,Si,Ca) at grain boundaries,achieving the most optimized power loss of 267 kW/m3 at 5 MHz (10 m T,100 ℃) and initial permeability of 644,which is much better than the previously reported results and commercial products.Such an improvement is attributed to weakened magnetic exchange coupling at grain-boundary regions,associated with a significant transition from the multi-to mono-domain structures,originating physi-cally from large crystallographic mis-orientations (＞25°).The present study bears important significance in understanding the intrinsic correlation between the crystallographic mis-orientation and magnetic domain structure,and provides an alternative way for optimizing high-frequency soft magnetic ferrites.     

MnZn铁氧体制备工艺研究进展

MnZn铁氧体是软磁材料的主要组成部分。首先介绍了MnZn铁氧体的最新研究动态，其制备工艺的好坏将直接影响到产品的优劣，然后综述了近年来制备MnZn铁氧体的新工艺和新技术，以及其结构特征和性能方面的突破，最后对MnZn铁氧体的发展进行了展望。     

Effect of Microwave Processing on Polycrystalline Hard Barium Hexaferrite

The present paper describes our results on the phase transformation (from crystalline to amorphous) of M-type hard barium hexaferrite, and consequently its conversion into soft ferrite by the application of magnetic energy at microwave frequency (2.45 GHz). The rapid volumetric heating of the conventionally prepared polycrystalline hexaferrite by microwave energy at a temperature of 950?°C in a short duration of only 5 min resulted in a decrystallized phase. The magnetic studies (M?CH loops) of the resistively heated and MW processed samples have revealed a lowering in coercivity (from 188 to 2 mT) in the latter samples, thereby establishing the formation of soft ferrite. An attempt has also been made to understand the observed transformation from hard to soft ferrite.     

NiZnFe_2O_4包覆铁基软磁复合材料的制备及性能

采用溶胶-凝胶法制备的NiZnFe_2O_4作为绝缘剂包覆铁粉来制备铁基软磁复合材料,并研究了NiZnFe_2O_4含量和成型压力对复合材料磁性能的影响。采用SEM,EDX线扫描及元素面分布分析显示在铁粉颗粒表面存在一层均匀的NiZnFe_2O_4包覆层,绝缘包覆层的存在可以有效地提高软磁复合材料的电阻率。实验结果表明,随着NiZnFe_2O_4包覆剂含量的增加,软磁复合材料的复数磁导率实部值逐渐降低,与其他含量的样品相比,NiZnFe_2O_4含量为3%(质量分数,下同)的样品具有最低的复数磁导率虚部值和相对较高的复数磁导率实部值。NiZnFe_2O_4包覆剂的加入,可以大幅降低材料内部的磁损耗,在100kHz时其磁损耗仅为未包覆样品的16.2%。当NiZnFe_2O_4的含量为3%,成型压力为1000MPa时,软磁复合材料的密度达到7.14g/cm~3,饱和磁感应强度为1.47T。     

Coexistence of Low Damping and Strong Magnetoelastic Coupling in Epitaxial Spinel Ferrite Thin Films

Low‐loss magnetization dynamics and strong magnetoelastic coupling are generally mutually exclusive properties due to opposing dependencies on spin–orbit interactions. So far, the lack of low‐damping, magnetostrictive ferrite films has hindered the development of power‐efficient magnetoelectric and acoustic spintronic devices. Here, magnetically soft epitaxial spinel NiZnAl‐ferrite thin films with an unusually low Gilbert damping parameter (<3 × 10^?3), as well as strong magnetoelastic coupling evidenced by a giant strain‐induced anisotropy field (≈1 T) and a sizable magnetostriction coefficient (≈10 ppm), are reported. This exceptional combination of low intrinsic damping and substantial magnetostriction arises from the cation chemistry of NiZnAl‐ferrite. At the same time, the coherently strained film structure suppresses extrinsic damping, enables soft magnetic behavior, and generates large easy‐plane magnetoelastic anisotropy. These findings provide a foundation for a new class of low‐loss, magnetoelastic thin film materials that are promising for spin‐mechanical devices.     

The Synthesis of Single-Crystalline BaFe12O19 Nanoparticles by Molten-Salt Method with Surfactant NP-9

Single-crystalline barium ferrite (BaFe₁₂O₁₉) nanoparticles have been successfully synthesized by the molten-salt method. The particles of both samples with and without surfactant NP-9 possess hexagonal plate-like shape. However, BaFe₁₂O₁₉ nanoparticles without NP-9 during the preparation exhibit two different magnetic phases (soft and hard) reflected from the double magnetic hysteresis loops, and the soft magnetic phase was attributed to the defect region in the nanoparticles. Including the surfactant NP-9 in the preparation process, the soft magnetic phase was effectively suppressed, and only the hard magnetic phase was observed, reflected from the single magnetic hysteresis loop. Furthermore, the remanent magnetization and saturate magnetization were increased slightly by using NP-9. These results indicate that NP-9 is an effective additive for the preparation of high-quality single-crystalline ferrite nanoparticles.     

Studies on the Relation between the Composition of Thermal Sensitive MnZn Ferrite and Curie Temperature

1. IntroductionThermal sensitive MnZn ferrite, only studied sincelater 10 y6arsl is a kind of soft magnetic materialand can be used to control temperature. Because ofits special feature that its magnetic conductivity willchange suddenly in the vicinity of TC, all types ofmagnetic thermal sensitive sensors have been manufactured with the feature of low TC, no aging, highreliability, small volume and low cost. These sensorshave been widely used in automatic temperature control and protection i…