Wettability of molten CaO-Al 2 O 3 -MgO slag on some refractory materials at 1773K

The interface characteristic of molten slag has an important effect on the interface phenomenon and reaction between molten slag and molten metal/refractory. The wettability of molten CaO-MgO-Al₂O₃ slag on some refractory materials (including Mo, graphite, boron nitride (BN), MgO and Al₂O₃) was studied in argon atmosphere at 1773 K. The contact angle between molten slag and substrate material was measured by the sessile drop method; the interfacial tension and work of adhesion were calculated by Young equation and Young-Dupré equation, respectively. The results showed that, except for graphite, the molten slag can well wet these materials, and the contact angle decreases with increasing temperature and eventually converges to a stable equilibrium value. The interfacial tension of different substrate materials is very different, and the interfacial tension between the slag and reactive substrate MgO, Al₂O₃ and graphite is small, ranging from 71 to 205 mN/m. The molten slag-Mo of the non-reactive substrate is 1323 mN/m and the molten slag-BN is 7297 mN/m. The adhesion work between molten slag and substrate is in the range of 800–1100 mJm⁻² except graphite, which is 400 mJm⁻².