| abstract |
Based on the total amount of oxides of the composition selected from ZrSiO 4 and Type I, Type II, and Type III sintering aids and combinations thereof, the following amounts of sintering aid: Type I : 0.0 to 0.1 wt% (Fe 2 O 3, SnO 2, oxide glass, and mixtures and combinations thereof); type II: 0.1 to 0.8 wt% (TiO 2, SiO 2, VO 2, CoO, NiO , selected from NbO and mixtures thereof and combinations); type III: from .0 to 0.8 wt% (Y 2 O 3, ZrO 2, CaO, MgO, Cr 2 O 3, A composite material substantially composed of Al 2 O 3 and mixtures and combinations thereof, and a process for producing these composite materials. The present invention is particularly useful for the production of large refractories that are resistant to creep at high operating temperatures, such as isopipes for the production of fusion draw glass. |