Tellurite And Fluorotellurite Glasses For Active And Passive

7. Surface properties; MDO 294
Wt. loss / %
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
3M H 2 SO 4
1M HCl
fit y=0.05346exp(x/36.75647) R 2 = 0.98082
fit y=0.10038exp(x/54.66244) R 2 = 0.94807
0 20 40 60 80 100 120
Time / sec.
Fig. (7.27): Etch rate of glass MOD012 (75TeO2-10ZnO-10Na2O-5GeO2 mol. %),
immersed in 1M HCl (•), and 3M H2SO4 (■) at 15°C.
It can be seen that the both solutions resulted in an approximately exponential growth
etch rate. The 3M H2SO4 etch initially showed a similar etch rate to the 1M HCl, but was
increased at longer times.
Fig. (7.28) shows the etch rates of glass MOD012 (75TeO2-10ZnO-10Na2O-5GeO2
mol. %), immersed in 1M HCl, 1M H2SO4, and 3M H2SO4 at 21°C (see section 7.1.2.1
for further experimental details).