Alumina refractories and ceramics are extensively applied in the steelmaking field due to their excellent properties, such as chemical resistance and high wear resistance at high temperature. [1] Besides this, the addition of graphite significantly improves the thermal shock resistance of alumina. Thanks to these properties, the application spectrum of Al 2 O 3 -C materials became very wide-from ladle refractory to submerged nozzle and filters. [2][3][4][5] Khanna et al. [6,7] investigated the interaction between pure Al 2 O 3 , Al 2 O 3 -12.9 mass % C, and molten iron using the sessile drop method at 1550 C between 15 min and 3 h. The authors reported a strong interaction between Al 2 O 3 ÀC and molten iron including COÀgas evolution, extensive iron penetration into the substrate, and refractory degradation, Fe 3 Al formation at the iron refractory interface, and Al 2 O 3 whiskers formation. In contrast, no Al 2 O 3 whiskers formation and penetration of molten iron into the refractory was found in investigations with pure Al 2 O 3 and molten iron. In addition, when a blank Al 2 O 3 -C sample was heated without the presence of molten iron under the same experimental conditions, no Al 2 O 3 whiskers formation could be detected. Khanna et al. [6,7] explained these phenomena through the carbothermic reduction of Al 2 O 3 and dissolution of the reduced aluminum into the liquid iron. Similar investigations with identical results were achieved by Ikram-Ul-Haq et al. [8] However, in earlier publications, the carbothermic reduction of alumina was reported under low pressure (0.08-0.2 atm) with the presence of Sn and Cu as a metallic solvent (from 1700 C to 1850 C) [9] or under vacuum conditions. [10] Nevertheless, the aforementioned explanations for carbothermic alumina reduction at low temperature were not supported by other researchers. [11] If equilibrium concentrations of Al and oxygen in Fe liquid are low, carbothermic reduction is not possible. Zienert et al. [11] conducted a thermodynamic simulation of the Al 2 O 3 ÀC/ Fe system to investigate the process of dissolution of Al and O in Fe liquid in the presence of C across the interface at the conditions of Khanna's [6] investigation. The reaction at every step in this simulation involved the dissolution of small amounts of alumina in liquid iron and the reaction of dissolved oxygen with carbon to CO formation. The amount of dissolved alumina in the simulation was defined from calculated molar densities, the assumed penetration rate, and the contact area and was assumed constant during the simulation. This continuous dissolution of alumina led to pick-up of aluminum in molten iron up to 9.75 at% in 3 h.Wei et al. [12] investigated the interaction between Al 2 O 3 ÀC and Fe in Al 2 O 3 ÀC crucible at 1600 C under argon atmosphere. Yan et al. [13] reported that the aluminum-bearing volatile species released strongly in the Al 2 O 3 ÀCÀFe system in the temperature range 1500-1520 C reacted with iron, which led to the formation of hercynite whiskers on the surface of a...
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