Sodium tracer diffusion in a glass-ceramic containing nano-sized spinel crystals

Tracer diffusion coefficients of sodium have been measured at temperatures between 400°C and 800°C in a glass-ceramic containing nano-crystalline spinel by employing the radioactive tracer Na-22. Diffusion profiles of Na-22 obtained in this two-phase glass-ceramic can be evaluated by assuming a single tracer diffusion coefficient for describing the diffusion on a macroscopic length scale. The values of the tracer diffusion coefficients obtained range from 4×10−10 to 3×10−7 cm2/s from 400°C to 800°C, respectively. A simple Arrhenius equation, D*Na=10(−1.86±0.08)exp(−(97.25±1.21 kJ/mol)/R T) cm2/s, can be used to summarize the data. Based on the results from separate sodium tracer diffusion experiments in spinel, it is concluded that the diffusion of sodium ions in the glass-ceramic is not significantly influenced by the presence of nano-sized spinel particles in this material.