Excellent electrical conductivity, resistance to corrosion, a much longer service life than lead anode, the ability to operate steadily for over 4,000 hours, and cheap cost make titanium anode an unavoidable trend for the growth of electroplating zinc and tin production both domestically and internationally. In addition to significantly reducing plating energy consumption, titanium electrodes are now utilized domestically in Japan, the US, and Germany. This is because they can raise the density of plating current, which enables the manufacturing of thick galvanized, tin steel plate.
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Classification of titanium anodes:
1. The precipitated oxidized gas is known as precipitated oxygen anode, such as iridium system coated titanium electrode and platinum titanium mesh/plate. The precipitated chlorine gas is known as precipitated chlorine anode, according to the differentiation of gas precipitated from anode in electrochemical reactions. Anode for chlorine precipitation (ruthenium-coated titanium electrode): the electrolyte contains a lot of chlorine ions, usually in environments with hydrochloric acid, salt water, or both. Our firm produces ruthenium-iridium titanium anode and ruthenium-iridium tin titanium anode as complementary items.
2. The electrolyte is typically in an atmosphere with sulfuric acid at the oxygen precipitation anode (iridium-coated titanium electrode). Iridium-tantalum anode, iridium-tantalum tin titanium anode, and high iridium titanium anode are the anodes that match our goods.
3. Titanium serves as the foundation material for the platinum-coated anode. Platinum is applied to the surface; the thickness of the coating is typically between 0.5 and 5 μm, and the platinum titanium mesh specifications are typically 12.5 x 4.5 mm or 6 x 3.5 mm.
During electrolytic operation, ruthenium-iridium titanium anodes have a certain operating life. The ruthenium-iridium-titanium anode loses its functionality when the voltage increases to a very high level and no current actually flows through; this is referred to as anode passivation.
The following justifies the passivation of ruthenium-iridium-titanium anodes.
a. Flaking coating
The titanium substrate and ruthenium iridium titanium active coating make up the titanium ruthenium iridium titanium anode; only the active coating contributes to the electrochemical process. The titanium ruthenium iridium titanium anode will lose its functionality if the coating and substrate are not strong enough to fuse together. It will fall off the titanium plate substrate to some extent. (Separated into peeling and cracking types of shedding, pulverized shedding, and convex belly-like layer shedding)
c. Dissolution of RuO2
By lowering the amount of oxygen present, oxide film formation can be slowed down. The rate of chlorine creation rises significantly faster than the rate of oxygen generation when the total current density of electrolysis rises; thus, the current density rises in favor of chlorine in the decrease of oxygen content. In order to prevent the ruthenium from falling off and dissolving, the titanium substrate is first pre-oxidized to create an oxide film. This can strengthen the bond between the titanium substrate and the ruthenium-iridium-titanium active coating and make the coating firm. However, it will also raise the ohmic drop of the ruthenium-iridium-titanium anode.
c. Saturation of oxide
Oxygen-deficient oxides, non-stoichiometric RuO2 and TiO2, make up the active coating. The actual activation centers of the chlorine discharge are the non-stoichiometric oxides. The ruthenium-iridium-titanium anode’s activity increases with the number of such oxides present because they create more active centers. The performance displayed by the aberrant n-type mixed crystals made from RuO2 and TiO2 of the same crystalline type by heat treatment, which contain some oxygen vacancies, is the conductivity of the ruthenium-iridium-titanium coated anode. When these oxygen vacancies are filled with oxygen, the overpotential quickly increases, resulting in passivation.
d. The coating cracks
Due to cracks in the active coating, some of the oxygen that is adsorbed on the anode surface diffuses or migrates through the active coating to reach the coating and the titanium plate substrate interface. The remaining oxygen is chemically adsorbed on the surface of titanium substrate and titanium to create a non-conductive oxide film (TiO2), which is not conductive. This electrolysis in the ruthenium-iridium titanium anode produces new ecological oxygen, some of which is discharged in the active coating and electrolyte interface, and then leaves the anode surface to generate oxygen into solution. After that, oxygen is chemically adsorbed on the titanium substrate’s surface, creating a non-conductive oxide film (TiO2) with titanium that creates a reverse resistance; alternatively, if the electrolyte penetrates the coating’s cracks, the titanium substrate gradually oxidizes and the interface with the ruthenium-iridium-titanium active coating corrodes, dislodging the active coating and increasing the potential of the ruthenium-iridium-titanium anode. The coating’s disintegration and the titanium substrate’s oxidation are further encouraged by the potential rise.
