전기폭발법에 의한 금속 및 세라믹 나노분말제조 = (The) Production of metal and ceramic nanopowders by pulsed wire evaporation(PWE) method

다국어 초록 (Multilingual Abstract)

Nanostructured materials are the materials with a microstructure the characteristic length scale of which is the order of a few (typically 1-10nm) nanometers. Nanostructered materials may be in or far away from thermodynamic equlibrium. Nanostructured materials, which are structurally characterized by ultrafine grains and a large volume fraction of grain boundaries, have drawn increasing attention in recent years.
Due to the high density of interface that may promote dynamic processing. Nanostructured materials exhibit apparently different physical, chemical, and mechanical properties from those of either the conventional polycrystalline or amorphous state. Therefore, the microstructure characteristic of the nanostructured materials interfaces, as well as there effects on the property enhancements are fundamentally important for this new class of materials. As a matter of fact, nanostructered materials exhibit different properties especially if they are generated by different preparation method. Among many techniques used to prepare nanostructured materials, the pulsed wire evaporation(PWE) method is a promising one. Provided a great impulse current, thin wires of metal or alloy in certain gas environment are exploded. This process is accompanied by an instantaneous discharge through energy release from capacitor banks. The advantage of this method are not only depended on its high productivity and time-saving, but also on its universal usage for preparing nanostructured materials, such as metals, florides, carbides and nitrides. Nanostructured materials prepared by pulsed wire evaporation process exhibit many special properties in comparison with those prepared by other methods. For example; (1) there intrinsically exists even high density of defects(vacancies, microvoids, dislocations etc); (2) exhibit more lower melting and sintering temperatures; (3) have a even larger volume fraction of amorphous; (4) exhibits high chemical activites; (5) stored even more enthalpy. The nanostructered materials prepared by PWE behave differently from other nanostructurecd materials due to these special characteristics, especially for their high-stored enthalpy and high chemical activities. Therefore, thermal stability and grain growth in nanostructured materials have attractered increasing scientific and technological interests since the appearance of nanostructured samples in recent year. To understand the structure of grain boundaries and the nature of grain growth in nanostructured materials, much intensive studies are highly needed in different kind of materials systems, as well as in nanostructured samples synthesized by means of various routes. In this study, produced metal and ceramic powder were characterized by several measuring methods. Transmission Electron Microscope(TEM) and Scanning Electron Microscope(SEM) showed particle shape and size. Also X-ray Diffraction patterns showed its crystal and measured particle size by Scherrer Equation.

목차 (Table of Contents)

• 목차 = Ⅰ
• List of figures = Ⅲ
• List of tables = Ⅴ
• ABSTRACT = Ⅵ
• 제1장. 서론 = 1
• 제2장. 이론 및 문헌적 배경 = 3
• 제1절. 나노분말의 제조기술 = 3
• 제2절. 전기폭발법 = 7
• 제3절. 전압과 분말생성조건과의 관계 = 10
• 제4절. 분말 형성거동 = 16
• 제5절. 전기폭발장치의 제조 = 19
• 제6절. 분말보관 및 취급기술 = 25
• 제3장. 금속 및 세라믹나노분말 제조 = 28
• 제1절. 출발원료 = 28
• 제2절. 실험방법 = 28
• 제3절. 결과 및 고찰 = 32
• 제3-1절. 나노 알루미늄 분말제조 = 32
• 제3-2절. 나노크기 구리 분말 제조 = 41
• 제3-3절. 나노 은, 니켈, 구리-니켈 분말제조 = 47
• 제3-4절. 나노크기 알루미나(Al_(2)O_(3)) 제조 = 53
• 제3-5절. 나노크기 산화구리 분말 제조 = 54
• 제4장. 결론 = 60
• 참고문헌 = 62
• 감사의글 = 66