Analysis on the causes of titanium anode passivation

In the process of electrolytic operation, the working life has a certain period of time. When the voltage rises so high that no current actually passes through, the anode loses its function, this kind of phenomenon called anode passivation. 

In the process of electrolytic operation, the working life has a certain period of time. When the voltage rises so high that no current actually passes through, the anode loses its function, this kind of phenomenon called anode passivation. 

Common phenomena and causes of titanium anode passivation:

The coating peeling off: titanium anode is composed of titanium basic and active coating, the effect of electrochemical reaction is only the active coating, if the coating and matrix bonding is not strong enough, from the matrix peeling down, peeling to a certain extent, the titanium anode will lose its role. It can be divided into crushing shedding, protruding layer stripping and cracking shedding.

Cracks in the coating: When the coating is cracked,another part of oxygen is adsorbed on the anode surface and reaches the interface between the coating and the titanium matrix through diffusion or migration. Then oxygen is chemically adsorbed on the surface of the titanium matrix and forms a non-conductive oxide film (Ti02) with titanium to generate reverse resistance.Or the titanium matrix is slowly oxidized, the active coating interface is shed by the corrosion coating, resulting in an increase in anode potential, which further promotes the dissolution of the coating and the oxidation of the titanium matrix.

Coating dissolution: There are two cases of coating dissolution, one is uniform dissolution of the entire anode surface, the other is localized dissolution somewhere in the anode, when the dissolution to a certain extent, the electrode will be passivated.

Oxide saturation: the isomorphic type in the coating anode is heat treated to form a distorted mixed crystal base with some oxygen vacancies. When these oxygen vacancies are filled with oxygen, the overpotential rises rapidly, resulting in passivation.

The actual situation of coated titanium anode passivation during electrolysis is very complicated. Is caused by a combination of factors. The working life of the electrode varies significantly with the coating formulation, electrolytic medium and operating conditions. In view of the causes of titanium anode passivation, our company has taken a series of anti-passivation measures. The service life of anode can be extended greatly.