It was found that ceramic-glass composites could be produced by the direct sintering of raw mixtures with a high SiO2 content. The conductivity decreased upon increasing the SiO2 content (table 74). When the K content was lower than 15mol%, the activation energy for conduction decreased with the K content. This was attributed to a decreased K jump distance. The activation energy of the composites decreased, with increasing radius of the lanthanide, from Dy to Sm. It then increased in going from Sm to La. This was explained in terms of changes in the electrostatic binding energy and strain energy of the mobile K. The elution of K with water was depressed upon increasing the SiO2 content and decreasing the radius of the added lanthanide.

S.Nakayama, Y.Sadaoka: Electrochimica Acta, 1995, 40[15], 2541-6

Table 74

Ionic Conductivity of K2O-Dy2O3-SiO2 Compositions