The structure of carbon nanotubes impregnated with Yttrium

Abstract

Observations have been made of the structures resulting when yttrium introduced into the carbon arc used to form carbon nanotubes with high resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) in bright-field modes and nanodiffraction with an electron beam of diameter about 1nm in the STEM instrument. Crystallites of the carbide, YC 2, are formed, some being enclosed in polyhedral multi-walled carbon particles. Many of the carbon nanotubes formed are bent or distorted. Some carbon nanotubes are partially or fully filled with an yttrium compound. Small, poorly-ordered crystallites of YC 2, or of a modified structure, provisionally designates as YC' 2, appear to grow epitaxially on the inner walls of the carbon nanotube with the YC 2 c-axis parallel to the circumference of the inner cylindrical wall of the carbon nanotube. Occasional cigar-shaped particles of metallic Y, coated with epitaxed carbide, are also observed.