The influence of the presence of tungsten of SF6 arc plasmas

The mass density, the specific heat at constant pressure and the electrical and thermal conductivities of thermal plasmas formed in SF6-tungsten vapour mixtures were calculated as a function of temperature, for molar concentrations of tungsten in the range 0-50% and for pressures 0.1-1 MPa. These properties are not really disturbed by the presence of tungsten for proportions lower than 10% except for the electrical conductivity, which increases with the proportion of tungsten at temperatures lower than 13000 K. The results given in this paper show that, for tungsten proportions under 10%, the properties of pure SF6 can be used, except for the electrical conductivity. For this last property, the values are very close to those of an SF6-Cu mixture of equivalent proportions.