Development of Refractory Ceramics That Can Be Processed at Temperatures Considerably Lower Than Their Maximum Use Temperature

摘要

The effort was divided into three temperature ranges. In the highest 3000F and high, the sintering characteristics of pure alumina, and plus additives, and pure spinel were studied. Pure alumina plus minor additions of magnesia have attained maturity at 2840F. Matured spinel has been realized at 2650F. In the temperature range 2600 to 3000F the presintered approach to the prereacted materials technique was used. Compositions in the high alumina portion of the CaO.Al2O3.SiO2 system were evaluated and compared to the earlier work in the MgO.Al2O3.SiO2 system. Properties, mechanisms and structure were discussed. In the lowest temperature range the devitrification approach to the prereacted raw materials technique was utilized. Cordierite (2MgO.2Al2O3.5SiO2) was the crystalline phase studied. Two approaches were used. In the first the whole composition is fritted and used as the sole raw material from which specimens were prepared. Compositions in the MgO.A12O3.SiO2 system were studied. In the second, two devitrifiable frits are prepared and used.