Corrosion behavior of silicon nitride bonded silicon carbide refractory material by molten copper and copper slag

The observation of the cross section of the exposed Si3N4-SiC plate on macro level shows 4-5 zones of different color. Microstructural observations show almost no changes of the material in direct contact with molten copper without exposure of air, that suggests slow dissolution of Silicon Carbide and Silicon Nitride in the flowing melt of copper (physical dissolution in case of permanent removal of reactants). The most severe wear of Si3N4-SiC refractory is by slag, because the chemical erosion takes place.