Corrosion mechanisms of Al2O3/MgAl2O4 by V2O5, NiO, Fe2O3 and vanadium slag

The effects of V2O5, NiO, Fe2O3 and vanadium slag on the corrosion of Al2O3 and MgAl2O4 have been investigated. The specimens of Al2O3 and MgAl2O4 with the respective oxides above mentioned were heated at 10 °C/min from room temperature up to three different temperatures: 1400, 1450 and 1500 °C. The corrosion mechanisms of each system were followed by XRD and SEM analyses. The results obtained showed that Al2O3 was less affected by the studied oxides than MgAl2O4. Alumina was only attacked by NiO forming NiAl2O4 spinel, while the MgAl2O4 spinel was attacked by V2O5 forming MgV2O6. It was also observed that Fe2O3 and Mg, Ni, V and Fe present in the vanadium slag diffused into Al2O3. On the other hand, the Fe2O3 and Ca, S, Si, Na, Mg, V and Fe diffused into the MgAl2O4 structure. Finally, the results obtained were compared with those predicted by the FactSage software.