Formation of liquid‐phase isolation layer on the corroded interface of MgO/Al2O3‐SiC‐C refractory and molten steel: Role of SiC

Abstract

AbstractFormation of a dense layer on corroded interface to suppress corrosion is always desired, but it is controlled by numerous environmental conditions. In this work, corroded microstructures of MgO/Al2O3‐SiC‐C refractories in metal bath area of ladle furnace were investigated after industrial trails. A liquid‐phase isolation layer in which MgO islands and liquid phases was established on the corroded interface of refractories with 6 wt% coarse/fine SiC‐additive. The formed isolation layer against steel/slag attacks led to an approximate 30% improvement in corrosion resistance than that of refractory with 3 wt% fine SiC‐additive. More importantly, the liquid‐phase isolation layer blocked the direct mass transfer between molten steel and refractories while it decreased exogenous pollution from refractories. SiC‐additive affected the formation process of isolation layer by controlling the generation/migration of Mg(g) on refractory' surface. A further formation mechanism of liquid‐phase isolation layer was discussed in detail and role of SiC was elucidated.