課題番号                ：S-19- NI-0030

利用形態                ：共同研究

利用課題名（日本語）    ：ナノカーボンのその場電子顕微鏡観察

Program Title (English) ： In Situ Transmission Electron Microscope of nanocarbon: Joule Heating Effect on Graphitization of Copper Incorporated Carbon Nanofiber

Username (English)     ：Mohd　Zamri　Bin　Mohd　Yusop ¹⁾

所属名（日本語）        ：1) マレーシア工科大学

Affiliation (English)  ：1) University of Technology Malaysia

１．概要（Summary ）

The Joule heating process on copper (Cu) incorporated carbon nanofiber (CNF) was investigated under the in-situ transmission electron microscope (TEM) facilities. The significant structural formation has occurred after the Joule heating process showing a single crystalline encapsulated graphitic structure with dramatic improvement on the graphitic structure of CNFs from amorphous to crystalline.

２．実験（Experimental）

We used a CNF sysnthesis system consisting of Kaufmann-type ion gun (Iontech. Inc. Ltd., model 3-1500-100FC) for growing CNFs. The diameter and ion beam energy employed for this experiment were 6 cm and 1 keV, respectively. The basal and working pressures were 1.5 × 10^-5 and 2.0 × 10^-2 Pa, respectively. The morphology of the Cu incorporated carbon nanofibers are grown on the edge of the Cu foils was carefully observed by scanning electron microscope [SEM (JEOL JSM-5600)] and the crystallinity of the sample was examined by TEM. We used a custom-made TEM sample holder (JEOL; EM – Z02154T) with a piezo-controlled tungsten (W) nanoprobe coated with gold (Au) to apply a bias voltage maintained at 200 mV with additional 200 kΩ on the Cu-CNF sample. The piezo-controlled nanoprobe is free to move in x, y, and z-axis directions controlled by the DC power system.

３．結果と考察（Results and Discussion）

A significant structural transformation of a Cu incorporated CNF fabricated on Cu foil was observed using in situ TEM facilities. After the applied bias voltage, the dramatic change in the Cu incorporated CNF structure from fibrous amorphous and very fine crystallites to the single-crystal encapsulated graphitic structure was observed. The randomly dispersed Cu nanoparticles were agglomerated and formed into a single crystalline structure whilst amorphous carbon transformed into the graphitic structure and covering the single crystalline particle. Joule heating would be responsible for the structural change of the Cu incorporated CNF.

４．その他・特記事項（Others）

The authors would like to express their appreciation for the support of the, HiCOE grant (R.J090301.7824.4J202), Flagship grant (Q.J130000.2424.03G36), GUP Tier 1 grant (Q.J130000.2524.16H37) and Ministry of Higher Education Malaysia (MOHE).

５．論文・学会発表（Publication/Presentation）

(1) M. ‘Azizir-Rahim, M. Zamri, M. H. D. Othman, Mona Ibrahim, and M. Tanemura, International Journal of Automotive and Mechanical Engineering, 16(3), 6931-6939 (2019).

６．関連特許（Patent）

None