| 摘要 |
? Synthetic raw materials are used to prepare a sintered refractory body consisting essentially of cordierite having 47.5 to 56 weight percent SiO2, 31 to 40 weight percent A12O3, 12 to 19 weight percent MgO, and 0.15 to 1 weight percent CaO, the body having a flexural strength of at least 138 MPa (20,000 psi). The cordierite body with respect to impurities, has less than 0.3 weight percent total alkaline earth metal oxides other than MgO and CaO, less than 250 ppm Na2O, less than 150 ppm K2O and less than 500 ppm transition metals on the oxide basis. Thus, the cordierite of the invention has very low impurity levels yet good sinterability and, hence, high strength. |
