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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Amorphous iron-chromium oxide nanoparticles prepared by sonochemistry
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Amorphous iron-chromium oxide nanoparticles prepared by sonochemistry

机译：声化学法制备的非晶态铁-氧化铬纳米粒子

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摘要

Amorphous Fe _2O _3 and Fe _(1.9)Cr _(0.1)O _3 materials have been prepared by sonochemical method. X-ray diffraction patterns, transmission electron microscopy, Raman and infrared spectra, differential scanning calorimetry, M?ssbauer and magnetic measurements revealed many interesting behaviors of the samples. Reaction to form the materials only occurred at the preparation temperatures of 70 °C or above. Upon heating, the sample prepared at 70°C presented a strong ferromagnetic behavior due to the presence of the magnetite phase coexisting with the hematite phase whereas the samples prepared at higher temperatures presented only the existence of the hematite phase. Thermal analyses of the sample prepared at 80°C revealed three exothermic peaks which were corresponding to the phase changes of dehydroxylation, crystallization of the maghemite phase and maghemite-hematite transition, respectively. The activation energies of the phase changes deduced from the thermal analyses showed that the presence of Cr enhanced the activation energy which can slow down the ageing effect of the amorphous state when being used in practice.
机译：通过声化学方法制备了非晶态的Fe _2O _3和Fe _（1.9）Cr _（0.1）O _3材料。 X射线衍射图谱，透射电子显微镜，拉曼光谱和红外光谱，差示扫描量热法，Msssbauer磁测量结果显示了样品的许多有趣行为。仅在70°C或更高的制备温度下发生反应以形成材料。在加热时，由于存在与赤铁矿相共存的磁铁矿相，因此在70°C下制备的样品表现出强的铁磁性能，而在较高温度下制备的样品仅呈现赤铁矿相的存在。在80°C下制备的样品的热分析显示了三个放热峰，分别对应于脱羟基的相变，磁赤铁矿相的结晶和磁赤铁矿-赤铁矿的转变。由热分析推导的相变的活化能表明，Cr的存在增强了活化能，在实际使用时会降低非晶态的老化作用。

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