The Ag+/Na+ ion-exchange was studied for Na2O·2SiO2 glass below and above the glass transition temperature using an eutectic melt, (AgCl)0.42(AgI)0.58. The interdiffusion coefficients were deduced from the Ag concentration profiles in the glass, as measured by means of X-ray micro-analysis. It was found that the diffusion could be described by:
D (cm2/s) = 1.3 x 10-2 exp[-77.1(kJ/mol)/RT]
at temperatures below the glass transition temperature, and by:
D (cm2/s) = 1.1 x 104 exp[-157(kJ/mol)/RT]
at temperatures above the glass transition temperature.
On the Interdiffusion of Ag+ and Na+ Ions in the Glass Na2O·2SiO2 around the Glass Transition Temperature. C.Kaps, G.Völksch: Journal of Non-Crystalline Solids, 1982, 53[1-2], 143-53
Table 175
Diffusivity of 22Na in 3SiO2•Na2O Glass
Method* | Temperature (C) | D (cm2/s) |
C | 299.5 | 7.82 x 10-10 |
E | 299.5 | 2.19 x 10-9 |
C | 302.0 | 7.67 x 10-10 |
E | 302.0 | 2.34 x 10-9 |
C | 349.1 | 2.21 x 10-9 |
E | 349.1 | 6.91 x 10-9 |
C | 350.0 | 2.52 x 10-9 |
E | 350.0 | 7.80 x 10-9 |
C | 380.0 | 3.92 x 10-8 |
E | 380.0 | 1.27 x 10-9 |
C | 382.0 | 5.06 x 10-8 |
E | 382.0 | 1.56 x 10-9 |
*C: Chemla technique, E: deduced from Einstein equation
Table 176
Mobility of 22Na in 3SiO2•Na2O Glass
Temperature (C) | μ (cm2/Vs) |
299.5 | 4.44 x 10-8 |
302.0 | 4.71 x 10-8 |
349.1 | 1.29 x 10-7 |
350.0 | 1.45 x 10-7 |
380.0 | 2.25 x 10-7 |
382.0 | 2.77 x 10-7 |