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天文系Colloquium:The gas environment of galaxies across 10 billion years
【图书馆系列讲座】个人文献管理软件EndNote的功能与使用
【图书馆系列讲座】如何使用LaTeX排版论文
环境学术沙龙第629期:系统规划,综合整治——城市黑臭水体治理的理论与实践探索
报告题目:
Fabrication and characterization of carbon-based biomorphic composites
 报告人:
Dr. Dickon H. L. Ng
Associate Professor
Department of Physics
The Chinese University of Hong Kong.
报告时间:
2005-11-04 14:30
报告地点:
焊接馆301室
主办单位:
机械系
  简介:

Bioorganic substances like woods or cellulose fibers can be converted into high strength and lightweight carbide-reinforced biomorphic composites. The preparation of these composites involves several steps: (i) transforming natural bioorganic structures to carbon-based bio-templates by drying and pyrolysis, (ii) wetting the carbon bio-templates by infiltration of gaseous or molten metals, or metal-organic solutions, and (iii) converting the wetted bio-templates to functional composites by heat treatment. Biomorphic products, synthesized by this technique, possess bioorganic structures as well as having superior properties of engineering composites of carbides. This presentation describes the synthesis and characterization of biomorphic SiO2/SiC/C and SiC/C composites that contained SiO2 and β-SiC nanostructures. Freshly cut Luk Bamboo (Bambusa Textilis var Fusca) slices were used as our starting material and converted to bio-templates, and the metal-organic tetraethylorhosilicate solution was utilized as a source for Si. In characterizing the products, we found that the tubular structure of bamboo was retained. In addition, micron-sized spheres and nanorods of SiO2 were observed on the walls of the vessels in the samples treated at temperature around 1200oC, while β-SiC nanobelts were found in those samples treated at about 1400oC.

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