Synthesis and Characterization of Various Cobalt Materials
Date Issued
2005
Date
2005
Author(s)
Huang, Fei-Ting
DOI
zh-TW
Abstract
The Objectives of the study are to synthesize and investigate various cobalt materials of different shapes like hexagonal flake, nanodisk, corn tassel and cobalt wire like caterpillar from cobalt nanoparticles.. The study also proposes a plausible mechanism of the formation of these cobalt materials.
In 1997, a new physical sputtering method has been reported to produce different shapes cobalt nanomaterials. On the other side, cobalt has three kinds of phases such as hexagonal close packing (hcp-P63/mmc), face center close packing (fcc-Fm3m) and cubic structure (cubic-P4132). As cobalt has superior potential for fabrication into various shapes, cobalt is chosen as the subject of this study. However, nowadays most systems are used in organic environment. The present study establishes an aqueous system which is having advantages of lower cost and easier control of experimental conditions such as the concentration, temperature, pH and capping agent.
The results show that the variation reactant concentration, magnetic force direction and zeta potential of cobalt materials lead to various shapes. For example this may be due to the increase of reactant concentration lowers the zeta potential of materials while slight variation of pH results in level of aggregation. TEM and SEM characterization techniques have been employed to study the interior porous structure of cobalt wire and to observe topography and size of materials, respectively. The study has also done MCD and EXAFS experiment in NSRRC to prove the nanostructure of inner cobalt wires.
The present study establishes an aqueous system to synthesize cobalt nanomaterials of different shapes and can be a promising technique to produce other magnetic materials in future.
Subjects
鈷
界面電位
磁圓偏振二向性
形狀
分散劑
鐵鎳
cobalt
MCD
shape
CTAB
zeta potential
nickel
iron
Type
thesis