Damage mechanism of postmortem Si-Al2O3 sliding gate adding containing Ti2O3 fused mullite

Abstract

The Si-Al2O3-fused mullite containing Ti2O3 composite was sintered at 1300 °C in N2 with a solid carbon. O′-Sialon, Ti(C, N)ss, SiC were formed in situ, and there was still free silicon. These non-oxide reinforced phases are not wetted by molten steel/slag and have excellent corrosion resistance. Therefore, the Si-Al2O3-fused mullite containing Ti2O3 after sintering at 1300 °C in N2 with solid carbon is a potential sliding gate material. It was made into a sliding gate and used at steel-making works to explore its damage mechanism. The results show that the postmortem sliding gate can be divided into a slag layer, a reaction layer, a transition layer and an unreacted layer. The reaction and transition layers are very thin, with thicknesses of 1 mm and 6 mm, respectively. In the reaction layer, Si, O′-Sialon and Ti(C, N)ss react with [O]steel to form SiO2 and TiO2 respectively, accompanied by volume expansion to form the dense layer, which inhibits the further penetration of molten steel/slag. In the transition layer, partial and active oxidation of Si occur simultaneously. The damage mechanism model of the sliding gate was established.