1992 Volume 100 Issue 1168 Pages 1448-1452
The effect of additives on the vitrification temperature was investigated using the isothermal method. Lime, talc and materials containing alkaline earth metals were added to porcelain bodies in the quartz-feldsparkaolinite system which were the representative ceramic composition for building construction. The alkaline earth metals of about 3% lowered the vitrification temperature of the body without affecting temperature sensitivity. The decrease in the vitrification temperature depended on the molar concentration of the alkaline earth metals irrespective of their kinds. In addition, the apparent viscosity of the body was evaluated from the pressure softening displacement, and the decrease in the vitrification temperature has been ascribed to the decrease in the apparent viscosity.
