Study on preparation of onion-like fullerenes by vacuum heat treatment Bao Huiqiang\ Zhang Yan\ Han Peide\ Li Tianbao\ Jia Husheng\ Liu Xuguang2(1. School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China; 2 Taiyuan University of Technology College of Chemical Engineering and Technology, Taiyuan 030024, China). The products were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The results show that after vacuum heat treatment at 800°C, a large amount of graphite chips, amorphous carbon spheres and metal particles are present in the product. After vacuum heat treatment at 1800°C, a large amount of OLFs appear in the product with high degree of crystallinity, and the structure is relatively perfect. More uniform (about 15~35 nm) In addition, the generation mechanism of OLFs was explored.
Look at the application of composite high-strength materials, magnetic materials, information materials, luminescent materials, conductive materials, electromagnetic wave absorption and electromagnetic shielding |4~61. Current methods for preparation of OLFs are: arc discharge method 1781, electron beam irradiation method 19, Radio-frequency plasma CVD method 110, low temperature heat treatment 1111 of bio-protein material, and the like. Due to the harsh requirements of the reaction conditions of the above methods, there are difficulties in the production of OLFs and the difficulty in separation, which limits the deeper research and practical application of OLFs.
Satoshi Tomita et al. performed vacuum heat treatment on diamond particles with a particle size of 5 nm. Subsequently, during the vacuum heat treatment of 1800C, the amorphous carbon spheres gradually crystallized and eventually formed OLFs. In the 800C vacuum heat treatment, Al was encapsulated in amorphous carbon. Incomplete evaporation, in the vacuum heat treatment process of 1800C, the amorphous carbon material is rapidly crystallized. During the step of cooling with the furnace, it diffuses into the carbon inside the liquid Al, and begins to precipitate and crystallize, finally forming OLFs with Al-containing inclusions. OLFs were prepared by two-step vacuum heat treatment method using graphite as carbon source. HRTEM and XRD analysis showed that the OLFs in the product were mostly quasi-spherical structures with high degree of crystallization, and the yield was about 10%. Based on the experimental results, the generation mechanism of OLFs was inferred. . The vacuum heat treatment method is easy to operate and low in cost, and can be provided for large-scale synthesis of OLFs.
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