Effect of ultrasonic wave irradiation on the electrical conductivity of the undoped and doped molten sulfur with some inorganic materials

The electrical conductivity and the activation energy of conduction were measured up to 340°C for undoped sulfur melts and doped sulfur melts with 5 mol% LiF, 5 mol% NaF, 13.4 mol% NaCl, 1 and 5 mol% KCl, 5 mol% NaBr, 5 mol% Se, 5 mol% NaBr + 5 mol% Se, 5 mol% Na₂SO₄, 5 and 10 mol% Na. The effect of irradiation of ultrasonic waves of 20 kHz was studied. The electrical conductivity generally increased with increasing temperature above 200°C with a variety of temperature dependencies. The addition of NaBr, Se, LiF, Na₂SO₄, NaBr + Se, and KCl caused an increase in conductivity in this order by max. two orders of magnitude. For sulfur melts doped with 5 and 10 mol% Na, a wide jump of electrical conductivity occurred at 245°C, giving exceedingly high electrical conductivities above this temperature. By the irradiation of ultrasonic waves, the electrical conductivity was raised together with the formation of jump for Se, NaBr + Se, 5 mol% Na, LiF, Na₂SO₄, NaBr, and NaF. The largest irradiation effect was observed for 10 mol% Na, for which the jump temperature was 190°C. The activation energies classified into low, medium, and high groups were obtained. The assumption of microscopic temperature was proposed, which was found to explain the electrical conductivity of irradiated melts.