During the electrolysis operation, the working life of the titanium electrode has a certain period of time. When the voltage rises so high that virtually no current flows, the titanium anode becomes ineffective, a phenomenon known as anode passivation.

Titanium electrode passivation has the following reasons:

1.Coating peeling off: The titanium anode is composed of a titanium substrate and active protrusions. It is only the active layer that plays the role of electrochemical reaction. If the bonding between the layer and the substrate is not strong enough, it will peel off from the substrate and peel off to a certain extent. The titanium anode will be ineffective.

2.There are cracks in the coating: due to the cracks in the active coating, new ecological oxygen is generated on the anode during electrolysis, a part of which will be adsorbed on the surface of the electrode, through the coating to reach the titanium substrate through diffusion or migration, and is non-conductive with titanium. oxide film, resulting in reverse resistance. Or the titanium substrate is slowly oxidized, the active coating interface is corroded, and the coating falls off, resulting in an increase in the potential of the titanium electrode, which further promotes the dissolution of the coating and the oxidation of the titanium substrate.

3.Coating dissolution: There are two kinds of coating dissolution, one is the uniform dissolution of the entire anode surface, the other is the partial dissolution of the anode somewhere, when the dissolution reaches a certain level, the titanium electrode will be passivated.

4.Oxidation such as saturation: There are some oxygen vacancies in the distorted mixed crystal matrix of the isomorph in the coated anode after heat treatment. When these oxygen vacancies are filled with oxygen, the overpotential rises rapidly, resulting in passivation.

5.The actual situation of the passivation of the coated titanium electrode during the electrolysis process is complex and changeable, which is caused by the combination of multiple factors. The working life of titanium electrodes varies significantly with coating formulations, electrolyte media, and operating conditions.