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排序方式: 共有4565条查询结果,搜索用时 11 毫秒
11.
Marcela Stoia Cornelia Păcurariu Ciprian Mihali Iosif Mălăescu Cătălin Nicolae Marin Aylin Căpraru 《Ceramics International》2019,45(2):2725-2735
Magnetic MnFe2O4 nanopowders were synthesized by an original solvothermal method in the absence and in the presence of tetra-n-butylammonium bromide (TBAB) and Tween 80 (TW) as surfactants. Manganese ferrite/polyaniline (PANI) hybrid materials were synthesized by in situ polymerization of aniline on the surface of MnFe2O4 using ammonium persulfate as oxidant. The purpose of the study was to investigate the influence of the two surfactants on the properties of the MnFe2O4 powders and of their composites with PANI. The specific surface area, the cumulative surface area of pores and the cumulative volume of pores are influenced by the nature of surfactant in case of MnFe2O4 powders and are higher by comparison to those of the MnFe2O4/PANI hybrid materials. The values of saturation magnetization in case of MnFe2O4 powders are higher than those of the hybrid materials and are not influenced by the surfactant nature. These features revealed that MnFe2O4 powders can be efficiently used as adsorbents for the purification of wastewaters. The values of the electrical conductivity of the composites exhibit a significant increase in comparison to the MnFe2O4 powders and depend on the surfactant nature. The highest value of electrical conductivity was achieved by the composite obtained using Tween 80 as surfactant (σDC = 54.5·10?5S?m?1) which was close to that of PANI (σDC = 61.2·10?5 S?m?1). The fact that the magnetic and electric properties of the synthesized MnFe2O4/PANI composites can be changed by design, demonstrate the high potential of these materials to be used in magneto-electric applications. 相似文献
12.
Based on the phase transformation theories, especially the T0 concept of bainite transformation, alloy optimisation of bainitic steel with carbides has been carried out aiming at the produce of plastic mould with large cross-section. The effect of manganese and silicon on proeutectoid ferrite and bainite transformation is explored by dilatometric analysis, XRD and different microscopy techniques. The results show that after the alloy optimisation, the transformation of proeutectoid ferrite is suppressed and when the cooling rate is lower than 0·1°C?s??1, the new lower bainite transformation appears by decreasing carbon capacity of austenite and promoting carbide precipitation. Industrial production proves that the optimised alloy SDP1 can meet the demand for the plastic mould with the thickness of 1050?mm. 相似文献
13.
Changwei Dun Guoxi Xi Ye Zhang Tingting Zhao Yumin Liu Xiaoying Heng Lu Yao 《Ceramics International》2018,44(17):20984-20991
In this study, we investigated the effects of substituting Li+ for Co2+ at the B sites of the spinel lattice on the structural, magnetic and magnetostrictive properties of cobalt ferrites. The Li+ substituted cobalt ferrites, Co1-xLixFe2O4, with x varying from 0 to 0.7 in 0.1 increments, were synthesized with a sol-gel auto-combustion method using the cathode materials of spent Li-ion batteries. X-ray diffraction analysis revealed that all the Co1-xLixFe2O4 nanopowders had a single-phase spinel structure and the lattice parameters decreased with increasing Li+ content, which can be proved by slight shifts towards higher diffraction angle values of the (311) peak. Field emission scanning electron microscopy was used to observe the fractured inner surface of the sintered cylindrical rods and the increased porosity resulted in a decreased magnetostriction. The oxidation states of Co and Fe in the cobalt ferrite samples were examined by X-ray photoelectron spectroscopy. High resolution transmission electron microscopy micrographs showed that most particles were roughly spherical and with sizes of 25–35?nm. Li+ substitution had a strong effect on the saturation magnetization and coercivity, which were characterized with a vibrating sample magnetometer. The Curie temperature was reduced due to the decrease in magnetic cations and the weakening of the exchange interactions. The magnetostrictive properties were influenced by the incorporation of Li+ at the B sites of the spinel structure and correlated with the changes in porosity, magnetocrystalline anisotropy and the cation distribution. 相似文献
14.
Ferrite particles coated with biocompatible phases can be used for hyperthermia treatment of cancer. We have synthesized substituted
calcium hexaferrite, which is not stable on its own but is stabilized with small substitution of La. Hexaferrite of chemical
composition (CaO)0.75(La203)0.20(Fe2O3)6 was prepared using citrate gel method. Hydroxyapatite was prepared by precipitating it from aqueous solution of Ca(NO3)2 and (NH4)2HPO4 maintaining pH above 11. Four different methods were used for coating of hydroxyapatite on ferrite particles. SEM with EDX
and X-ray diffraction analysis shows clear evidence of coating of hydroxyapatite on ferrite particles. These coated ferrite
particles exhibited coercive field up to 2 kOe, which could be made useful for hysteresis heating in hyperthermia. Studies
by culturing BHK-21 cells and WBC over the samples show evidence of biocompatibility. SEM micrographs and cell counts give
clear indication of cell growth on the surface of the sample. Finally coated ferrite particle was implanted in Kasaulli mouse
to test its biocompatibility. The magnetic properties and biocompatibility studies show that these hydroxyapatite coated ferrites
could be useful for hyperthermia. 相似文献
15.
16.
单轴-平面W型复合锶铁氧体的制备及其吸波特性研究 总被引:3,自引:0,他引:3
用草酸盐共沉淀和微量掺杂法研制六角晶系W型Ni,Zn,Co,Al多元复合锶铁氧体,通过调节Ni2W同Co2W的摩尔比例,可使该种铁氧体易磁化方向从C单轴型向垂于C轴的平面型转化,控制置换锶铁氧体中部分Fe3 的微量掺杂Al3 ,可以调整4πMs值,提高磁晶各向异性场,测试分析了5种不同含Co量的W型复合锶铁氧体粉料涂层的吸波特性,发现其自然共振吸收峰随Co含量增加向低频方向偏移,最高吸收峰可达32.8dB,是适用于电子隐形技术的高品位的微波吸收剂。 相似文献
17.
研制了一种新型微合金非调质钢。通过合理设计合金成分,改善熔炼脱氧过程,控制钢中氧化物的组成、分布、形状和尺寸,在研制钢中形成微细的氧化物夹杂作为晶内铁素体最有利的析出位置。通过晶内铁素体的析出细化了晶粒,提高了钢的强度与韧性。将研制的新型微合金非调质钢用于拖拉机的牵引插销是可行且有效的。 相似文献
18.
Hun Xue 《Materials Letters》2007,61(2):347-350
Macroporous nanocrystalline zinc ferrite with single spinel-phase was prepared by a facile self-propagating combustion method using zinc nitrate, iron nitrate and glycine. The as-prepared ZnFe2O4 were characterized by X-ray diffraction (XRD) analysis, N2 adsorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectrum (EDS). The magnetic properties of the prepared ZnFe2O4 were also studied. 相似文献
19.
低碳微合金钢中的晶内铁素体及组织控制 总被引:1,自引:0,他引:1
回顾和评述了晶内铁素体的发现、发展及其与组织控制的关系.介绍了晶内铁素体的形核机制和影响晶内铁素体形成的因素,讨论了晶内铁素体的三维形态和长大动力学,并从以上几方面分析了晶内铁素体对低碳微合金钢组织细化的重要作用和影响. 相似文献
20.
中国软磁铁氧体用氧化铁 总被引:1,自引:0,他引:1
介绍了中国软磁铁氧体用氧化铁的发展历史和现状,预测了未来的市场需求,并探讨了氧化铁的应用技术问题。 相似文献