Abstract
The interfacial tension measurements were made for liquid slag-liquid metal interfaces with the sessile drop method. A radiographic technique was used to determine the profile of an aluminum-, or sulfur-containing iron drop which was placed on an alumina substrate and covered by a layerof CaO-SiO2-Al2O3 slag in an alumina or a graphite crucible.
An anomalous decrease in the interfacial tension was observed for iron melts containing more than 2% aluminum. This decrease, which resulted in the interfacial tension of less than 100 dyne/cm, was proved to be due to brisk reduction of silica by aluminum. For sulfur-containing iron saturated with carbon, desulfurizing took place, and the interfacial tension was considerably decreased to less than 500 dyne/cm only when the rate of sulfur transfer exceeded 3-10-6 mol/min/cm2. Whenever this criterion was exceeded, marked disturbance resulting in a serrated interface was observed at the slag-metal boundary.
