Diffusion of tin (IV) in silicate glazes and glasses

The diffusion coefficients of Sn(IV) in an aluminosilicate glass and a commercial glaze have been measured from 809 to 1505° C. Two experimental techniques have been used. In one method, single crystals of SnO₂ were embedded in either the powdered glass or sealed into a bar of the glass. After the diffusion anneal, the Sn(IV) concentration profile was determined by EPMA. In the other method, radioactive ¹¹³Sn was used as a tracer and the profile determined by measuring the X-ray emission. The results gave a good agreement between the two methods. The diffusion coefficients in the glaze ranged from 7×10^-20 m² sec^-1 at 809° C to 1.9×10^-14 m² sec^-1 at 1250° C and in the glass, from 5.6×10^-15 m² sec^-1 at 1307° C to 1.6×10^-11 m² sec^-1 at 1505° C.