Oxide refractories - two types of AZT ceramic and an Al_2O_3-rich magnesium aluminate spinel ceramic containing aluminum titanate - have been investigated. The AZT ceramics were prepared from a 95 wt% Al_2O_3 - 2.5 wt% ZrO_2 - 2.5 wt% TiO_2 powder mixture. The ceramics sintered at 1650 °C had a high thermal shock resistance. Their strength after quenching from 1200 °C was higher than the original strength after sintering, both after one and five quenching cycles. The thermal shock resistance of the Al_2O_3-rich spinel ceramic was improved by the addition of 12 wt% of pre-synthesized aluminum titanate. Higher strength after thermal shock in comparison with the as-sintered samples was not reached in this case, but compared with the pure spinel ceramic, the retained strength after repeated quenching from 950 °C or 1150 °C was higher when the ceramic contained aluminum titanate.
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