Why the Stability of Coated Titanium Anode is Important?

Why the Stability of Coated Titanium Anode is Important?

The need for a stable electrode for the chlorine-alkali industry led to the invention of the coated titanium anode, and so the importance of electrode coating stability can not be overemphasized. The stability of an electrode may be defined in terms of its lifetime. It measures the time it takes for the coated oxide electrode to be deactivated or fail in the electrolysis cell. For coated titanium anodes, stability is the ability of the electrode to function effectively in the application for which it was designed for longer periods. For example, the stability of RuO2 and IrO2-based electrodes may be defined in terms of their ability to evolve chlorine and/or oxygen at a relatively constant cell potential and current in chloride and /or acid solutions over long periods of time.

In general, anode deactivation/ failure is regarded as the rapid increase in cell potential when operating at constant current density or the rapid decrease in current density when operating at constant cell potential. The former definition is adopted for this work. Thus, the electrode is considered to have reached the deactivation /failure threshold when at a constant current density, the cell voltage begins to rise rapidly from the onset voltage. For coated titanium anodes, failure of the oxide electrode can occur at the substrate/coating interface or the coating/electrolyte interface.