Formation of carbon nanotubes and their filling with metallic fibers on ion-emitting field anodes

Detailed descriptions are given of the formation of carbon nanotubes and their filling with metallic fibers developing on field anodes in the so-called “anode activation” process. Unlike the multishell carbon nanotubes produced in arc plasmas, these carbon nanotubes are not perfectly graphitized. The metallic fibers grown inside the nanotubes contain chromium as their major component, but their structure does not conform to any of the known compounds of Cr nor to elemental Cr. The growth morphology and lateral dimension of metallic fibers are governed by those of their host nanotubes, thus falling into the category of “template-mediated” crystal growth. Evidence is also presented that the metallic fibers epitaxially promote the graphitization of the carbon nanotubes.