Liquid-state diffusion of Na2O–CaO–SiO2 system

Abstract
The concentration distributions after liquid‐state diffusion at 1200°C were measured by using an electron probe microanalyzer for two diffusion couples with an average composition of 16Na2O⋅12CaO⋅72SiO2 (wt%). The diffusion profiles agreed satisfactorily with the theoretical profiles calculated by the five‐component diffusion equations derived from the Nernst–Planck equation with assumptions of two oxygen ionic species with differing diffusivities and the oxygen density conservation.