Nanowear characteristics of carbon nanotube film made by surface decomposition of SiC

Abstract

This paper shows the wear characteristics of carbon nanotube films made by surface decomposition of SiC. By this method, one can obtain remarkably high density of CNTs with well vertical alignment. For the purpose of measuring the wear characteristics of CNT films with submicrometer thickness, we carried out nanoscratch and nanoindentation tests by using an atomic force microscope (AFM). And we used 2 kinds of AFM cantilever tips with tip radii of about 20 nm and 150 nm. The experimental results showed wear behaviors of CNT films dependent on CNT length and normal load. And CNT films were worn gradually as the number of wear cycles increased. The effect of CNT length on wear of CNT films appeared as different behaviors of CNT films under normal load. That was originated from bending stiffness of each CNTs with different length as measured by nanoindentation. Shorter-CNT films had less wear because of higher deformation resistance than longer ones. Under the normal load, the SCD tip penetrated to several tens of nanometers in depth, but the CNT films showed only wear depth on the order of angstrom for each scratch cycle. Thus we confirmed that CNT films have both strength and flexibility, which reflects remarkable mechanical properties of CNTs. These results are important for machine designs using CNT films as friction materials. Copyright © 2010 by JSME.