Transactions of the INDIAN CERAMIC SOCIETY Vol. 59 2000
Thermodynamic Activity of Oxides of Vanadium
in Sodium Borovanadate Glasses
R. S. Singh and S. P. Singh
Pages : 78-80
DOI : 10.1080/0371750X.2000.10799937
Abstract
Thermodynamic activity of the oxides of vanadium was studied
in sodium borovanadate glasses equilibrated with v 4+ .y5+ redox
system at 1000° and 1400°C in air. The ratio of logarithm of
activity coefficient, log[Yv 0 ]112/[Yvo ] was constant over a limited
2 5 2
range of 2.5-7.5 mol% concentration of V20 5 at 1000°C and 2.5-
10.0 mol% at 1400°C. It was found to deviate from Henrys law
beyond 7.5 mol% V20 5 at 1000°C in air. The value of log[~ )112·
• • V205
[Yvo ] m sod1um borovanadate glass equilibrated at 1000°C was
found to be greater than that of 1400°C. This indicated that the
V4+.yS+ system shifted more towards the reduced state with in·
creasing temperature. Further, it was observed that the curve
deviated from the Henrys line with increasing mol% of V20 5 or
decreasing mol% of Na20 at 1000°C.
