1)Minimal coefficient of expansion 2)Thermal shock stability 3)High load softening point 4)High bulk density INDEXITEMSM45AL2O3,%41-43Fe2O3,% ≤0.50SiO2,% ≥53-55TiO2,% ≤0.80CaO,% ≤0.30MgO,% ≤0.30Na2O,% ≤0.20K2O,% ≤1.50Mullite phase,%≥55 Amorphous state SiO2 glass,% ≥45 linear expansion test,(20-1000°C)/K-1 ≤4.4X10-6Real gravity,g/cm3 ≥2.70Bulk density ,g/cm32.50-2.60True Porosity,% ≤8Hardness7- ...