| abstract |
A high-zirconia cast refractory material which contains 85-95 wt % of ZrO 2 , 4-12 wt % of SiO 2 , 0.1 to less than 0.8 wt % of Al 2 O 3 , less than 0.04 wt % of Na 2 O, 0.01-0.15 wt % of K 2 O, 0.1-1.5 wt % of B 2 O 3 , 0.01-0.2 wt % of CaO, less than 0.4 wt % of BaO, less than 0.2 wt % of SrO, 0.05-0.4 wt % of Y 2 O 3 , and 0.3 wt % or less of Fe 2 O 3 and TiO 2 together, but does not substantially contain CuO and P 2 O 5 (less than 0.01 wt %), such that the molar ratio of the glass-forming oxides (such as SiO 2 and B 2 O 3 ) to the glass-modifying oxides (such as Na 2 O, K 2 O, CaO, MgO, SrO, and BaO) is 20-100, said refractory material having an electric resistance being 200 Ω·cm or higher after standing for 12 hours at 1500° C. |