Wettability between Porous MgAl2O4 Substrates and Molten Iron

The wettability between porous MgAl2O4 substrates and molten iron was investigated by the sessile drop method at 1833 K as a basic study in order to elucidate the interactions between molten iron and a refractory material. For the study, MgAl2O4 substrates with 2, 8, 13, 27, and 39% porosity were prepared. The contact angle increased with the substrate porosity. In substrates with 2%, 8%, and 13% porosity, the contact angles were independent of time. In contrast, for substrates with 27% and 39% porosity, the contact angle decreased rapidly during the first hour and then gradually reached a steady value. The decrease in contact angle with time was attributed to the interfacial free energy. The work of adhesion was 1.27 J·m−2, and it was suggested that the interfacial bond consists of not only a physical bond but also a chemical bond.