A preparation and optical property study of Nanostructured-Metal Materials

2017 Fiscal Year Annual Research Report

• Project/Area Number: 17F17793
• Research Institution: Tohoku University
• Principal Investigator: 平田 秋彦 東北大学, 材料科学高等研究所, 准教授 (90350488)
• Co-Investigator(Kenkyū-buntansha): XIA YANJIE 東北大学, 材料科学高等研究所, 外国人特別研究員
• Project Period (FY): 2017-11-10 – 2020-03-31
• Keywords: nanoporous materials

Outline of Annual Research Achievements

Recently our group has reported a new environmentally friendly method for vapor phase dealloying to fabricate novel nanoporous materials. This new method mainly utilizes a difference in vapor pressure between the constituent elements of alloys to selectively remove one of the components with a high partial vapor pressure. However the detailed mechanism of vapor phase dealloying has not been clarified so far.
In this study, we used a Zn-Cu alloy system to examine a difference in diffusion depth for the two elements. By vapor phase dealloying, the nanoporous Cu has been prepared from a Zn-Cu alloy at 350 degreeC and 400 degreeC in low vacuum for different times, ranging from 10 minutes to 110 minutes. The changes of depth and element distribution with the change of time have been characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. For 10 minutes, there are almost no pores in the sample. With the increase of dealloying time, the pores gradually appear. Comparing these samples, we found that the dealloying depth increases with time. It might be possible to understand the dealloying depth’s functional dependence on time and temperature by dissolution model.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

The research has been carried out properly along the initial plan that aimed at fabricating alloy-based hybrid nanostructures with porosity. However, we have found that the alloy ribbon is not suitable for fabrication. We now start to use bulk materials to improve the materails.

Strategy for Future Research Activity

After the investigation related to the depth analysis, we have obtained the above-mentioned experimental data of the diffusion kinetics. In the next step, we will provide a reasonable model to understand the diffusion kinetics of the dealloying process.