2012 Fiscal Year Final Research Report

Effective load transfer at CNT/matrix interface by intentional formation of nanocarbides on the surface of carbon nanotubes.

Research Project

Project/Area Number	23656445
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Material processing/treatments
Research Institution	Tohoku University
Principal Investigator	KAWASAKI Akira 東北大学, 大学院・工学研究科, 教授 (50177664)
Project Period (FY)	2011 – 2012
Keywords	粉末冶金
Research Abstract	This report summarizes the fabrication of chromium (Cr) carbide nanostructures on multiwalled carbon nanotubes (MWCNTs) in a MWCNT-copper (Cu) composite by adding small amounts of Cr. A single nanocrystal of carbide was epitaxially grown on the sidewallof chemically treated MWCNTs through the diffusion of solute Cr atoms to defects in the MWCNTs. Carbide has an island-shaped morphologywith a maximum size of several hundred nanometers. The phase of the generated Cr carbide nanostructures was mostly Cr7C3,as determined by electron beam diffraction using the nanobeam diffraction mode of a transmission electron microscope. In particular, theCr carbide nanostructures formed at radially unzipped sites were connected to the outermost wall and some inner walls of the MWCNTs.This is expected to increase the load-bearing capacity of the MWNCTs because the inner walls contribute to the load transfer, which isvery effective for improving the mechanical and thermomechanical properties of the composites.