A Study on the Interfacial Reaction Between Liquid Iron and MgO-Based Refractories Containing TiO2

Abstract

The interfacial reactions between liquid iron and MgO-based refractories were investigated based on the TiO2 concentration values. Substrates comprising MgO, MgO-TiO2 (MT), MgO-Al2O3 (MA), and MgO-Al2O3, at loadings of 3, 6, 9, 12, and 15 wt pct TiO2 (MAT3-15), were reacted with liquid iron at 1823 K by using the sessile drop technique. Microscopic analysis by SEM/EDX and the associated thermochemical calculations by Factsage 7.0™ confirmed the reaction mechanisms of different refractory materials. MgO and MT showed higher resistance against liquid iron penetration compared with MA and MAT3-15, which was attributed to the formation of a magnesiowustite (MO (M = Fe, Mg)) layer formed at the interfaces. Increasing the levels of TiO2 up to 6 wt pct contributed to the denser microstructure of MA. However, the contact angle was lowest for 9 wt pct of TiO2 and then gradually increased up to 15 wt pct. Chemical reactions generating a liquid slag phase contributed to the fluctuations in contact angle with respect to TiO2.