Investigation on a postmortem Al-Al2O3-fused mullite-containing Ti2O3 sliding gate

A resin-bonded Al-Al2O3-fused mullite containing Ti2O3 sliding gate was prepared from metallic Al, tabular alumina and fused mullite containingTi2O3, and was used at the steel-making works. XRD, SEM and EDS analyses were used to investigate the damage mechanism of the postmortem sliding gate. The results show that non-oxide-reinforced phases such as Al4C3, SiC, Al4O4C, Al2OC-AlNss and Ti(C,N)ss are formed which effectively improve the thermal shock and erosion resistance. And the service life of the sliding gate with a fused mullite content of 30 wt% reaches 4 cycles. The phase evolution of the postmortem sliding gate can be described as follows: the oxygen partial pressure is at a very low level due to the active oxidation reaction of the Al. At this time, the Ti2O3 in the fused mullite is unstable and transforms towards the more stable Ti(C,N)ss, while releasing O2. O2 further reacts with the Al to form the highly reactive Al2O(g). The highly reactive Al2O(g), AlN reacts with phenolic resin residual carbon or graphite to form Al2OC-AlNss. As the content of high titanium fused mullite increases, Al4O4C and Al4C3 gradually transform into the more stable Al2OC-AlNss and Ti(C,N)ss. The introduction of Al and high titanium fused mullite enables the synergistic formation of high performance Ti(C,N)ss and Al2OC-AlNss.