Results and Discussion
Thickness and Growth Rate of Solid Films
The thicknesses of traditional and ultrahigh-basicity solid slag films after different probe immersion times are shown in Fig. 2, and the corresponding average growth rates for the different time periods are shown in Fig. 3. As expected, film thickness does not increase linearly with time. For the TB flux, the average growth rate of solid films from 0 to 15 s of probe immersion is relatively high (approximately
Fig. 2 Thickness of slag film after different probe immersion times in 1400 °C molten flux (The error bar shows the uniformity of the film thickness at different immersion times)
Fig. 3 Average growth rates of solid slag films for different probe immersion periods
110 im/s), but lower (around 30 ^m/s) for longer times, up to 60 s. For the HB flux, the average growth rate of films gradually decreases from approximately 70 im/s (0-15 s) to approximately 3 im/s (45-60 s). The thickness of films become stable after the probe immersion time exceeds 45 s. If a thick film (as observed for the TB flux) was to form under mold conditions, the expected decrease in the thickness and uniformity of the liquid films might lead to lubrication difficulties.