IONIC-CONDUCTIVITY IN LOW CARNEGIEITE COMPOSITIONS BASED ON NAALSIO4

Carnegieite compositions of the type Na1+xAl1+xSi1-xO4 with x = 0 to ∼0.7 were prepared. Na ion conductivities, measured with Na and Au electrodes at ∼103 Hz, range from 4×10-5 (Ω-cm)-1 for NaAlSiO4 to 5×10-3 (Ω-cm)-1 at 300 C for Na1.7Al1.7Si0.3O4. Substitutions of Li, K, Ca, or Sr for Na lowered σ whereas substitution of Ti for Si raised σ. Na aluminum silicates with the nepheline structure had lower σ than carnegieite compositions. © 1979.