Nitride Capacity of the Molten CaO-SiO₂-Al₂O₃ System Containing TiO₂ or ZrO₂ and Equilibrated with Molten Si

Abstract

Nitride capacity of molten CaO-SiO₂-Al₂O₃ containing TiO₂ or ZrO₂ was observed. The molten oxides were equilibrated with nitrogen gas of 1013 hPa and with metallic Si to controll acculately oxygen partial pressure in the oxide phase. The experimental procedure was developed by the authors.
It is estimated that oxygen partial pressure in the molten oxide phase was controlled by the following reaction equation.
CaO-SiO₂-Al₂O₃ system: Si+ O₂ = SiO₂
CaO-SiO₂-Al₂O₃-TiO₂ system: TiO₂+4Si+O₂=TiSi₂+2SiO₂
CaO-SiO₂-Al₂O₃-ZrO₂ system: ZrO₂+4Si+ O₂=ZrSi₂+2SiO₂
The nitride capacities measured by the procedure are comparatively same as that reported by other investigators.