Synthesis of carbides in arc discharge plasma and their identification

Metal carbides have broad application in many fields. Their synthesis at high temperatures in a vacuum or inert gas is one of the best methods of their production. In this work, we report on the carbide formation in the argon arc discharge with graphite electrodes. The evaporated metal (or silicon) is placed inside the anode hole. The X-ray diffractions showed that under these conditions the following carbide substances are formed: Fe 3C with a concentration c of c = 23 %, SiC - c = 75 %, TiC - c = 40 %, WC - c = 3 %. The rest of the substances are predominantly structures of hexagonal graphite. The evaporating product of (C-Fe) anode is an exception to thisrule. This substance contains pure iron, the volume of which amounts to 55 %. It is assumed that iron particles form a metal core covered by a carbon shell. In fact electron micrographs show some spherical objects about 1-2 mkm in diameter. The chemical composition of the objects investigated by the electron X-ray spectroscopy is about to 37 at.% Fe and 63 at.% C. Raman Spectra (RS) of some investigated powders show some strips of phonon oscillations of some carbides and D- and G-lines of the graphite. There are two narrow maximums at 126 cm -1 and 139 cm -1 in the RS spectrum of anode (C-Fe) evaporated products. These maximums are attributed to an atom radial vibration in single-walled carbon nanotubes. Thus, based on this method carbides of some metals such as iron, titan, silicon, and tungsten can be synthesized in argon arc discharge with graphite electrodes