Which reference electrode is predominantly used in seawater?

The reference electrode predominantly used in seawater is the Saturated Silver Chloride (SSC) electrode. This electrode is favored due to its stable and reliable potential in saline environments, such as seawater. The SSC electrode provides a consistent reference point for measuring corrosion potentials, which is essential in marine cathodic protection applications.

When used in seawater, the SSC electrode maintains a relatively constant potential, making it ideal for accurate measurements in such corrosive conditions. Its design allows for minimal interference from the highly variable ion concentrations found in seawater, ensuring that the readings taken during cathodic protection assessments are dependable.

In contrast, the other electrodes mentioned have limitations in marine applications. The Calomel electrode, while historically significant, is less commonly used due to sensitivity to variations in chloride concentration. The Copper-sulfate electrode, although suitable for soil applications, is not as reliable in seawater due to the presence of competing ions that can affect its stability. The standard Silver electrode also presents challenges in seawater because it is more susceptible to changes in the local environment, which can alter its reference potential.

Overall, the SSC electrode's robustness and stability in saline conditions make it the predominant choice for cathodic protection systems applied in seawater.