Predominant Particles in SF₆-CO₂ Mixture at Temperatures of 300-30,000K

Abstract

Regarding SF₆-CO₂ mixture gases, the equilibrium compositions in a temperature range from 300 to 30,000K at 0.6MPa were calculated to find out predominant particles with high number densities. Eighty-five particles, including 47 neutral molecules originating from SF₆ and CO₂, were taken into account as the component species. At the temperatures T of about 7,000K or above, S, F, C, O, their positive ions and electrons are present as the predominant particles, for almost all of the CO₂ concentration, X_CO2 . Not only SF, SF₂, CO and CO₂ but also SO and SO₂ behave as the predominant particles in the temperature range from 3,000 to 7,000K, almost independent of X_CO2. On the contrary, the predominant particles in the temperature range from 300 to 3,000K distinctly depend on X_CO2. By way of example, for the gas of X_CO2=0.1, three particles SF₆, SO₂F₂ and CF₄ have the high number densities at T below 1,000K. By way of another example, particles CO₂, SO₂F₂, CF₄ and CO₂F₂, for X_CO2=0.6, shows the high number densities at T below 1,000K. On the basis of these results, the predominant particles present after an arc extinction are discussed as a function of X_CO2.