Ceramics-Silikáty 15, (4) 333 - 341 (1971)

The diffusion coefficients of sodium ions were measured in a melt containing 34.1 % by wt. of Na₂O by two methods using the Na²² radioactive isotope: the instantaneous plane source method and the method of diffusion couples with extended initial distribution. Another series of experiments was concerned with measuring the D value for Na²² in a diffusion couple with a concentration gradient of 10 % Na₂O. The results are discussed from the standpoint of the diffusion mechanisms in oxidic systems.