Abstract
For the purpose of making clear the behaviour of Al2O3 and SiO2 particles in liquid steel in terms of the wettability, we determined the surface tension of liquid pure iron and Fe-C alloys and the contact angles of Al2O3 and SiO2 formed with liquid pure iron and Fe-C alloys at 1240°, 1435° and 1560°C by the sessile drop method.
The main results obtained are summarized as follows: (1) Measurements at 1240°C with the use of Fe-C alloy containing about 3.90% carbon show that the contact angle increases rapidly with increasing surface roughness of the SiO2 substrate and decreases to a constant value in the first few minutes after melt down of Fe-C alloy, while in the case of the Al2O3 substrate, it decreases more slowly. They also show that the SiO2 substrate is considered to be slightly more wetted than Al2O3 substrate. (2) Measurements at 1435°C show that the wettability of Al2O3 and SiO2 by liquid Fe-C alloys is considered not to vary very much in the range of about 1.7∼3.3% carbon content. (3) From the results obtained it may be concluded that both Al2O3 and SiO2 particles tend to aggregate in liquid pure iron and Fe-C alloys and that the wetting of Al2O3 and SiO2 by liquid Fe-C alloys is induced by the chemical interaction at the boundary of separation.
