| 摘要 |
A high-zirconia cast refractory material which contains 85-95 wt % of ZrO2, 4-12 wt % of SiO2, 0.1 to less than 0.8 wt % of Al2O3, less than 0.04 wt % of Na2O, 0.01-0.15 wt % of K2O, 0.1-1.5 wt % of B2O3, 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 Y2O3, and 0.3 wt % or less of Fe2O3 and TiO2 together, but does not substantially contain CuO and P2O5 (less than 0.01 wt %), such that the molar ratio of the glass-forming oxides (such as SiO2 and B2O3) to the glass-modifying oxides (such as Na2O, K2O, CaO, MgO, SrO, and BaO) is 20-100, said refractory material having an electric resistance being 200 &OHgr;·cm or higher after standing for 12 hours at 1500° C.
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