Effect of MgO on wetting and corrosion behaviour of corundum substrate by CaO-SiO2-MgO (-Al2O3) slags

摘要

Effect of MgO content on wetting and corrosion behaviour of corundum substrate by CaO-SiO2-MgO (-15%Al2O3) molten slags was investigated at 1450 degrees C via joint application of a sessile drop technique, SEM-EDS detection and FactSage thermodynamic software. All slags exhibit good wettability on the substrate, and the contact angle values are small. Increasing MgO content from 7% to 9% in CaO-SiO2-MgO slags can increase the contact angle between the droplet and the substrate, while the substrate dissolution thickness and the slag penetration depth tend to decrease. Increasing MgO content from 8% to 15% in CaO-SiO2-MgO-15% Al2O3 slags can also increase the contact angle, but significantly decrease the slag penetration depth. The indirect dissolution thickness increases instead due to the formation of a large amount of MgAl2O4 by the interface reaction. The wettability can give an indication of the slag penetration depth in the substrate but not the dissolution thickness of the substrate.

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