Dynamic surface tension measurements on molten metal-oxygen systems: model validation on molten tin

A theoretical model on oxygen transport at the surface of liquid metals has been validated by dynamic surface tension measurements performed on liquid tin as test metal. The oxygen contamination conditions have been obtained at different oxygen partial pressures under low total pressure conditions (Knudsen regime), confirming that an oxide removal regime occurs under an oxygen partial pressure much higher than the equilibrium one (the "Effective Oxidation Pressure"). Experimental results are reported which give a new insight on the relative importance of the various processes due to the oxygen mass transport between the liquid metal and the gas phase. The critical aspects involved in surface tension measurements of liquid metals, related to the problem of liquid metal-oxygen interactions, are also carefully underlined. (C) 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.