Phenomenon of Whiskers Formation in Al<sub>2</sub>O<sub>3</sub>−C Refractories
Xingwen Wei, Anton Yehorov, Enrico Storti, Steffen Dudczig, Olga Fabrichnaya, Christos G. Aneziris, Olena Volkova
Abstract
Pure alumina (Al 2 O 3 ) and carbon‐bonded alumina (Al 2 O 3 −C) are used to investigate their interaction with iron (Armco) at 1625 °C, applying the sessile drop method. The investigations are conducted inside a heating microscope for 1 h under argon atmosphere with low oxygen partial pressure. No whiskers formation is observed from the experiments with pure Al 2 O 3 and molten iron. In the case of Al 2 O 3 −C/Fe system, several phenomena including the decarburization of Al 2 O 3 −C, Al 2 O 3 −C dissolution in molten iron, Al 2 O 3 layer formation on the iron droplet, and Al 2 O 3 whiskers formation are observed. To clarify the possible influence of iron on Al 2 O 3 whiskers formation, blank Al 2 O 3 −C samples without the presence of iron are heated and held in a half‐sealed platinum crucible at 1550 °C for 2 h. Thereby, the Al 2 O 3 whiskers formation is detected. Finally, the experimental investigations are supported with thermodynamic simulations.