Electrochemical measurement of oxygen activity in lead glass by means of a stabilized ZrO2 sensor Part 3. Measurement of the diffusion coefficient of oxygen

Abstract

The diffusion coefficient of oxygen is determined with respect to the evolution of the oxygen potential measured at one point of a glass column in the electrochemical cell as well as with respect to time and temperature; subsequently Fick's equation is solved. The measurements are made an the same glass, first with a refining agent, then without one. The results are compared with the values estimated from Eyring's model of viscosity. Different values are found; this would prove the existence of two diffusing species and two distinct diffusion mechanisms as other researchers have recently shown. By applying Eryring's model the diffusion coefficient can be measured according to the relation: lg D* = - 5.40 - 9740/T. By the same way, a glass without a refining agent is investigated by the electrochemical method according to the equation: lg D = - 5.54 - 6548/T. The electrochemical study of a glass with a refining agent shows the following relation: lg D= - 5.56 - 5852/T.