Surficial Decoration And Characterization Of Microstructure For Low-dimension Nanostruced Materials

Nowadays, low-dimension nano-structured materials have comprehensive applications such as chemical industry, metallurgy, environmental protection, mechanism, biology, medicine, aviations, magnetic materials and optical materials because of their specially physical and chemical properties. And with the development of nano-structured materials and their technology, their future applications are limitless. However, low-dimension nano-structured materials have higher surface energy and easily aggregate, on the other hand they exist many defects resulted from synthetic methods which now is not developed well. Therefore their applications are limited by these factors mentioned above. In the thesis, the study of surficial decoration for low-dimension nano-structured materials indicates that their dispersed property and surficial properties is improved distinctly at the same time.In the thesis, the low-dimension nano-structured materials such as a -Fe, a -SiC nanoparticles and carbon nanotubes are decorated by chemical methods, and their microstructures are characterized. Of those contents, a-Fe nanoparticles are synthesized by gas-liquid chemical reaction, and simultaneously the surfaces of them are decorated. In the paper, the influence of synthetic parameters on particle size,dispersion, the thickness of decorated layer and anti-oxidation of a -Fe nanoparticles. and the process conditions of the synthesis and surficial decoration of a -Fe nanoparticles are determined. The characterization of microstructure revealed the synthesized a-Fe nanoparticles in a great measure have new shape-pentagon or hexagon, the thickness of coated layer is about 4 nm, which is as 1/4 times as the size of a -Fe nanoparticles, and their dispersion is improved distinctly. The hystersis loops of a -Fe nanoparticles show that they possess ferromagnetism.In the paper, the surficial decoration for a -SiC nanoparticles is also studied firstly, the experimental results indicate that pre-treatments are key to their surficial decoration. By the pre-treatments metallic nickel nanoparticles deposit on the surface of a-SiC nanoparticles, and the process of this surficial decoration for a -SiC nanoparticles also supply a new process approach for other non-metal nanoparticles. The results of EDS spectra, atomic images and high-magnification TEM images reveal that nickel has been deposited on the surface of silicon carbide nanoparticles and the deposited nickel and silicon carbide are bound tightly.As for surficial decoration for carbon nanotubes also used chemical method, that is, electroless plating. In this paper, purification process of carbon nanotubes and pre-treatments of surficial decoration for them are studied carefully, andthe experimental conditions of surf icial decoration for carbon nanotubes on a large scale are optimized. Scanning electron microcopy images show that metal nickel or cobalt are uniformly deposited on the surface of carbon nanotubes.In addition, the mechanism of surficial decoration for those low-dimension nano-structured materials is studied simply.