Patent ID: 6576580
Filing Date: 2003-06-10
Classification: C04B

Abstract:
Oxidized alumina-zirconia-silica (AZS) refractories containing 40 wt % to 55 wt % Al2O3, 32 wt % to 45 wt % ZrO2, 10 wt % to less than 16 wt % SiO2 and 1 wt % to 3 wt % of an alkali metal oxide selected from Na2O, K2O and mixtures thereof, having a microstructure essentially comprising alpha-alumina crystals, free zirconia crystals, eutectic crystals and an intercrystalline vitreous phase, refractories wherein, at least in an active area thereof, more than 20% by number of said free zirconia crystals have a dendritic shape and are interleaved with each other and with eutectic crystals and at least 40% by number of said free zirconia crystals having a dendritic shape have a dimension greater than 300 &mgr;m.