Thermodynamic properties of He/Ar/N₂/C/Ni/Co thermal plasmas used in carbon nanotube synthesis

This work aims to study thermodynamic properties of Ar/He/N₂/C/Ni/Co plasma mixtures used in carbon nanotubes (CNTs) synthesis. Assuming a local thermodynamic equilibrium (LTE) and based on the composition results, calculated values are obtained for a temperature range of 1000–30 000 K and pressure in the range of 3–100 kPa. We have examined the influences of the chamber volume (60, 25 and 18 l) and plasmagen gases on the thermodynamic properties. We have also investigated the influence of metal/carbon vapors, which form part of the plasma gas mixture from approximately 2500 K. In this paper, many thermodynamic properties, mainly mass density, specific enthalpy and specific heat at constant pressure, are presented in detail through figures and tables. In total, we have considered 25 plasma configurations. In addition to the customary used description, each studied configuration is described through constituent elements proportion in order to standardize these data to be appropriate to a wide range of studies and setups other than the arc plasma reactor. (paper)