TN 4 Element Selection Dry Silver/Silver Choride

Dry silver/silver chloride elements consist of 99.99% pure silver coated with silver chloride.  Reference electrodes using this element are constructed so the external electrolyte comes into direct contact with the element.  Dry type elements are most commonly used in clean full strength seawater. Like the gelled Ag/AgCl elements, they are adversely affected by sulfides. The reference potential of dry Ag/AgCl elements immersed in full strength seawater is 70 mV negative to that of a saturated Cu/CuSO4 reference electrode.  As the ambient chloride level decreases, as would be the case when used in brackish water, the reference potential becomes less positive. Dry Ag/AgCl elements are only available in through-wall, immersion and tubesheet mounted reference electrodes.

Dry silver/silver chloride elements for concrete are a variation of our standard dry Ag/AgCl element which has been adapted for encasement in a cement-based grout. The reference potential depends on the pore water chloride level of the concrete structure in which it is embedded. In concrete immersed in seawater, the pore water chloride level equilibrates with that of the surrounding ocean so that the element provides long term stable service.     This element is only available in our Marine Concrete reference electrode.

If you find these technical notes interesting, please share them with your colleagues. Encourage them to periodically visit our blog for new, and hopefully useful, technical notes.