With a Y-Ni alloy composite graphite rod as anode for d.c. are discharge, a cloth-like soot was produced, containing about 40% single wall carbon nanotubes (SWCNTs). By characterization with high resolution transmission electron microscope (HREM) and Raman spectroscopy, it is found that the SWCNTs have nearly the same diameter of 1.3 nm and belong to armchair (n, n) type carbon nanotubes (n = 8, 9, 10 and 11). It is also proposed that a large temperature gradient and the addition of Y-Ni alloy in the anode are the two most important factors influencing the formation of SWCNTs. (C) 1999 Elsevier Science Ltd. All rights reserved.