In-Situ Reactions and Properties of Alumina-Magnesia Refractory Castables with Addition of TiO2
In the present work, the phase composition, apparent porosity, permanent linear change and microstructure were examined in castables containing 0–2 mass-% of TiO2 with and without magnesia to investigate the effect of TiO2 on in-situ reactions and properties in alumina-magnesia refractory castables after calcination at 1450°C/5 h. The results show that the addition of TiO2 can modify in-situ reactions and sintering processes. The amounts of spinel and calcium hexaaluminate (CA6) formed in overall castables increased with TiO2 addition, and the grain size of CA6 decreased gradually. The difference of the phase composition in overall and the matrix of castables indicated that the aggregates were involved in the CA6 formation. The permanent linear change and cold modulus of rupture of castables were dependent on TiO2 addition. For design of alumina-magnesia refractory castables, TiO2 could be used as an alternative to achieve good strength and certain expansion.
Keywordscastables TiO2 spinel calcium hexaaluminate
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