Showing papers by "Tadashi Maki published in 1975"

Study on crystallization of glass by differential thermal analysis. Effect of added oxide on crystallization of Li2O-SiO2

Abstract: Differential thermal analysis was made of 33.3 Li2O·66.7 SiO2·3 ROn and 25 Li2O·75 SiO2·3 ROn glasses, where ROn is an added oxide. The exothermic temperatures, Tc, due to the precipitation of lithium disilicate crystal, were plotted against the ionic radius of the cation of the added oxide. It was possible to classify the added oxides into a few groups on the basis of the valency of the cation. Within each group, the Tc increased as the ionic radius of the cation increased. It was shown that the temperature, Tη corresponding to the viscosity of 1010 P also increased with increasing the radius of the cation. The relation between Tc and Tη was discussed using the theory on the rates of nucleation and crystal growth. The effect of phase separation on Tc was also discussed.