Non-obvious Problems in Clark Electrode Application at Elevated Temperature and Ways of Their Elimination
Figure 6
States of the closed oxygen sensor before and after four cycles of warming-up/cooling (gas bubbles are indicated by arrows): (a) initial state, (b) after the use of medium saturated with atmospheric air, (c) after the use of medium depleted of dissolved gases. A view of the sensor with the cathode side is shown. For 4-cycle heating/cooling in all cases (b, c) there is negligible corrosion of the zinc anode and the appearance of salt deposits on the inner side of the membrane. If the heating takes place in medium saturated with atmospheric oxygen (b), the changes are more pronounced and in addition the formation of gas bubbles is observed. When heating is carried out in the medium depleted of dissolved gases (c), after the experiment, condition of the sensor does not differ from the initial (a).
