Investigation of the Wetting Characteristics of Liquid Iron on Mullite by Sessile Drop Technique

In the present work, reactions occurring between molten iron containing varying amounts of oxygen and mullite substrate were investigated through optical Sessile drop experiments. The reactions were followed in static as well as dynamic modes through contact angle measurements. Further, the reactions were followed as functions of time, temperature and oxygen partial pressure. The latter was changed by means of imposing a gas mixture of Ar-CO-CO2 into the furnace. The results showed that the contact angle between the substrate and the iron in purified argon gas was lower than the contact angles reported in literature for alumina and silica. Formation of a ternary slag during the reaction was observed and was subjected to SEM and EDS analysis. The thermodynamic criteria for slag formation and possible mechanisms of the reaction are discussed in the light of the experiments. The results are of relevance in understanding the mechanism of corrosion of aluminosilicate refractories by molten iron.