液相共沉淀法制备铁酸锰纳米粉

以六水合氯化铁和四水合氯化锰为原料，氢氧化钠为沉淀剂，采用液相共沉淀法制备出了纳米级铁酸锰颗粒，通过X射线衍射（XRD）分析，证实了该产物的主要成分为具有尖晶石结构的铁酸锰颗粒；通过HRTEM研究表明，由该法所制备得到的纳米铁酸锰粒子主要呈椭球形，粒径分布较窄，平均粒径在5－10nm。

纳米铁及氧化铁粉制备技术的进展

纳米铁及氧化铁粉广泛用于磁记录、气敏元件、光吸收材料、高效催化等领域。近年来,纳米铁及氧化铁粉的制备技术和物性研究取得了较大进展,应用领域进一步扩展。该文着重介绍国内外纳米铁及氧化铁粉的几种基本制备方法及其关键技术的发展现状,并分析了用不同方法制备的纳米粉末的物理特性。

纳米晶MnFe_2O_4的低温共沉淀法合成及表征

In this article,MnFe2O4 nanocrystals were synthesized by coprecipitation at low temperature,and the effects of temperature,time and additive on crystallization and particle sizes of samples were also studied.In addition,the samples prepared by the method were characterized by XRD,TEM and VSM,respectively.

超细铁酸镉材料的制备及其气敏性能研究

以FeSO4·7H2O和CdCl2·2.5H2O为原料,采用化学共沉淀法制备了纳米尺寸CdFe2O4粉体。利用X射线衍射仪、透射电镜对粉体的形貌、结构进行了表征。研究表明,用化学共沉淀法制备的CdFe2O4结晶情况良好,分布均匀,平均粒径约为80 nm。以CdFe2O4纳米粉体为原料制备了厚膜气敏元件,在工作温度为400 左右时,该元件对乙醇具有较高的灵敏度、好的稳定性和选择性。并对气敏机理给予了解释。

凝胶网格法制备纳米CdFe_2O_4粉体及其对CH_3SH的气敏性

以无机盐为原料,采用凝胶网格法合成了尖晶石型复合氧化物CdFe2O4的前驱体,并在700°C热处理后得到了纳米尺寸CdFe2O4粉体,利用XRD和TEM对粉体的形貌、结构进行了表征。研究表明,用凝胶网格法制备的CdFe2O4结晶良好,粒度分布均匀,平均粒径为21.3 nm。以CdFe2O4纳米粉体为原料制备了厚膜型气敏元件。CdFe2O4是电子导电型半导体,当加热电压为6.5 V时,该元件对甲硫醇具有较高的灵敏度,较好的稳定性和选择性。

A comparison of soft magnetic composites designed from different ferromagnetic powders and phenolic resins

Soft magnetic composites （SMCs） were prepared from three different ferromagnetic powder particles： iron powder ASC 100.29, spherical FeSi particles and vitroperm （Fe73CulNb3Si16B7） flakes. Two types of hybrid organic-inorganic phenolic resins modified with either silica nanoparticles or boron were used to design a thin insulating layer perfect- ly covering the ferromagnetic particles. Fourier transform infrared （FTIR） spectrometry confirmed an incorporation of silica or boron into the polymer matrix, which manifested itself through an improved thermal stability of the hybrid resins verified by thermogravimetric-differential scanning calorimetry （TG-DSC） analysis. The core-shell particles prepared from the ferromagnetic powder particles and the modified hybrid resins were further compacted to the cylindrical and toroidal shapes for the mechanical, electrical and magnetic testing. A uniform distribution of the resin between the ferromagnetic particles was evidenced by scanning electron microscope （SEM） analysis, which was also reflected in a rather high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in SMC consisting of the iron powder and phenolic resin modified with boron. The coercive fields of the prepared samples were comparable with the commercial SMCs.

紫外-可见光谱法检测十二烷基苯磺酸钠分散铁酸锌薄膜的光学气敏性能

以无机盐为原料,液相法合成了铁酸锌(ZnFe_2O_4)纳米粉体,通过X射线衍射仪和透射电子显微镜等手段对粉体的晶体结构和形貌等进行表征。以十二烷基苯磺酸钠(SDBS)作为分散剂,配制SDBS分散ZnFe_2O_4溶液,利用旋转甩涂法将其固定于锡掺杂玻璃表面,制成SDBS分散ZnFe_2O_4薄膜,并利用紫外-可见光谱法检测其光学气敏性能。实验结果表明,粉体为尖晶石结构,平均粒径约为14nm。SDBS分散ZnFe_2O_4薄膜对H2S气体有较好的灵敏度,对体积分数为(×10-3(V/V))的H_2S气体透光率变化可达1.190%,相对透光率为0.01202;可检测出H_2S气体的最低体积分数为1.0×10-7(V/V)。