Homogeneous Dispersion of Carbon Nanotubes on Surface-Modified Bulk Titanium Substrates by Thermal Chemical Vapor Deposition

Catalytic syntheses of CNTs on the pristine Ti mesh, the pristine Ti plate and the etched Ti plate have been conducted using thermal chemical vapor deposition (CVD) with Fe catalysts. Surface of the pristine Ti plate was etched in a sulfuric acid (H₂SO₄) solution to facilitate the uniform dispersion of Fe catalysts. The surface of Ti substrates, the distribution and the composition of catalysts, and the structure and dispersion of the CNTs were examined using Scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), electron probe micro-analysis (EPMA) and Micro-Raman spectroscopy. Fe catalysts were dispersed uniformly on the surface of the etched Ti plate indicating that Surface modification by etching was effective. CNTs on the pristine Ti mesh and the etched Ti plate are more densely populated and have smaller diameters than CNTs on the pristine Ti plate. These results can be attributed to smaller Fe catalysts more homogeneously distributed on the pristine Ti mesh and the etched Ti plate. The calculated I _G/I _D ratios of 1.02 and 0.97 for CNTs on the pristine Ti mesh and the etched Ti plate, respectively, indicate a high degree of structural disorders on CNTs.