RUI: Carbon Encapsulated Magnetic Particles

[405941] Parvin本研究着重于碳包封材料的合成、纯化、磁提取、结构和磁性表征。磁性合金（铁过渡金属合金、钴过渡金属合金、镍过渡金属合金和富铁稀土合金R2Fe17，其中R为稀土元素）的碳包覆颗粒在标准富勒烯电弧室中合成。一种利用磁矩与磁场梯度相互作用从非磁性物质中提取磁性粒子的有效方法。表征包括使用扫描电子显微镜（SEM）进行粒度分布分析，使用透射电子显微镜（TEM）进行成分和结构表征以及x射线衍射分析（XRD）。材料的磁性是通过直接测量粒子的磁矩在很宽的温度和磁场范围内进行研究的。有关含铁样品磁性质的附加信息是在一系列穆斯堡尔光谱测量中确定的。这项资助是一项涉及圣何塞州立大学、SRI国际和E.I. duPont de Nemours的合作研究项目。SRI国际是材料的合成，纯化，磁萃取和XRD研究的网站。扫描电镜和透射电镜工作在杜邦公司完成，磁强计和穆斯堡尔光谱在圣何塞州立大学进行。这种材料之所以引起人们的兴趣，是因为它们结合了封闭碳多面体的防腐蚀性能和理想的铁磁性能，可以通过选择要封装的颗粒和加工条件来定制。＊＊＊

9405941 Parvin This research emphasizes synthesis purification, magnetic extraction, and structural and magnetic characterization of carbon- encapsulated materials. The carbon-encapsulated particles of magnetic alloys (iron-transition metal alloys, cobalt-transition metal alloys, nickel-transition metal alloys, and iron-rich rare earth alloy R2Fe17, where R is a rare earth element) are synthesized in a standard fullerene arc chamber. An efficient method extracts the magnetic particles from nonmagnetic species using interaction of magnetic moments with a magnetic field gradient. Characterization includes particle size distribution analysis using scanning electron microscopy (SEM), compositional and structural characterization using transmission electron microscopy (TEM), and x-ray diffraction analysis (XRD). The magnetic nature of the materials is studied using direct measurements of the magnetic moment of the particles over a wide range of temperature and magnetic field. Additional information concerning the magnetic nature of the iron-containing samples is determined in a series of Mossbauer spectroscopy measurements. This grant is a collaborative research project involving San Jose State University, SRI International, and E.I. duPont de Nemours. SRI international is the site for synthesis, purification, and magnetic extraction of the materials and XRD studies. SEM and TEM work is done at DuPont, and magnetometry and Mossbauer spectroscopy is carried out at San Jose State University. %%% Such materials are of interest because they combine corrosion protection from the closed carbon polyhedra and desirable ferromagnetic properties that can be tailored by the choice of particles to be encapsulated and the processing conditions. ***