Reaction between MgO-SiO2 refractory material and Fe-Al alloy

Abstract

The interaction between molten Fe-Al alloy containing 5.1 wt.% aluminium and MgO-SiO2-based refractory was investigated. In high-frequency induction furnace at 1550 °C refractory samples were immersed in liquid alloy for 1 min, 2 min, 10 min, 20 min, 30 min and 60 min. Scanning electron microscope was employed to investigate phases at the interface and inclusions in the Fe-Al alloy. Forsterite phase in refractory was transformed to MgO·Al2O3 spinel, owing to the reduction of iron oxide and silica in forsterite by aluminium in the Fe-Al alloy at the interface. The interface layer separated locally from the refractory material and formed cluster and single particles in the Fe-Al alloy. In view on the reaction rate, the disintegration of the refractory material increased the reaction area but interfered with increasing thickness of the spinel layer. The dissolution rate of silica into the molten alloy decreased with increasing the reaction time because of the slowed down transport of aluminium diffusing through increasing spinel layer became the rate controlling step.