For each sensor cell (containing about 2.5 mL of 10% KOH solution), what is the typical lead weight?
The B-2C trace oxygen sensor is based on an electrochemical system with a silver-plated electrode as the cathode, lead as the anode (pressed granular lead), and an aqueous solution of 10% potassium hydroxide as electrolyte. The following drawing shows a cross-sectional view of the sensor. In the presence of oxygen, the sensor creates a current that flows from cathode to the anode as a result of the following electro-chemical reactions: Cathode: 02 + 2H20 + 4e- —–> 4OH- Anode: 2Pb –> 2Pb2+ +4e- A standard B-2C has 6 grams of lead in solid form when the cell is made. After the cell has been used, the solid lead is slightly reduced and the ionic lead inside the electrolyte increased. The ionic form of lead in 10% KOH is at the ppm level. The life of this sensor will depend on the history of the sensor, such as how long it has being exposure to high oxygen levels and / or how long it has been used.
