Phenomenon of Whiskers Formation in Al2O3-C Refractories

Pure alumina (Al2O3) and carbon-bonded alumina (Al2O3-C) are used to investigate their interaction with iron (Armco) at 1625 degrees 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 Al2O3 and molten iron. In the case of Al2O3-C/Fe system, several phenomena including the decarburization of Al2O3-C, Al2O3-C dissolution in molten iron, Al2O3 layer formation on the iron droplet, and Al2O3 whiskers formation are observed. To clarify the possible influence of iron on Al2O3 whiskers formation, blank Al2O3-C samples without the presence of iron are heated and held in a half-sealed platinum crucible at 1550 degrees C for 2 h. Thereby, the Al2O3 whiskers formation is detected. Finally, the experimental investigations are supported with thermodynamic simulations.

Automated summary

The interactions between pure alumina and carbon-bonded alumina with iron at high temperatures were investigated, revealing phenomena such as decarburization, dissolution, layer formation, and whiskers formation. Additionally, the formation of Al2O3 whiskers was detected even in the absence of iron, supporting the experimental findings. Thermodynamic simulations further supported the experimental investigations.