INTERFACIAL-TENSIONS OF LIQUID FE-NI ALLOYS AND STAINLESS-STEELS IN CONTACT WITH CAO-SIO2-AL2O3-BASED SLAGS AT 1550-DEGREES-C

In the present work, the interfacial tensions of Fe-Ni alloys in conta ct with slags of the CaO-Al2O3-SiO2 system were measured at 1550 degre es C. Nickel additions to the alloy were found to decrease interfacial tension. The effects of alumina and titania additions to the slag on the interfacial tension of the Fe-20 wt pet Ni alloy were determined: alumina was found to increase the interfacial tension by a small amoun t, while titania was found to decrease it drastically. Using the prese nt interfacial tension data for the CaO-Al2O3-SiO2 system and the ones measured by Jimbo and Cramb, Girifalco and Good's interaction coeffic ient (phi) was determined as a function of the slag composition using regression analysis and was found to be a useful means of correlating interfacial tension data. The interfacial tension of an Fe-20 wt pet N i-2.39 wt pct Al alloy in contact with a CaO-Al(2)O3-SiO2 slag was fou nd to decrease drastically in the first 60 to 75 minutes of the experi ment due to the dynamic effects of mass transfer. Slight lowering of i nterfacial tensions of industrial stainless steels due to sulfur trans fer from liquid metal to slag was also observed. The equilibrium inter facial tensions of type 304 stainless steels were found to be more dep endent on the slag chemistry than on the nickel and chromium content o f the alloy.