Ionic Conductivity in Glass and Glass‐Ceramics of the Na3YSi3 O 9 and Na5YSi4 O 12 Type Materials

Abstract

The ionic conductivities in glass and glass‐ceramics were studied for compounds. The results showed comparable conductivity values, in the range of 10−4 (Ω‐cm)−1 at 280°C, with the glasses being somewhat better conductors. Compounds of the type , which yielded highly conductive phases in the crystalline ceramic form, were also studied in glassy and glass‐ceramic states. In compositions of the latter type, the glasses showed lower conductivity than that in the glass‐ceramic or the conventional ceramic phase. However, glass‐ceramic samples with showed lower activation energies (4.0–4.4 kcal/mol) compared with those in the conventional crystalline phase prepared by Shannon et al. (1). The greater conductivity of the glass‐ceramic state in the phases, compared to the glassy state, is understood in terms of the favorable structure for ionic transport in the crystalline state.