A titanium electrode is a particular type of electrode that uses titanium metal as the substrate and, after sintering and oxidation, creates an oxide coating with electrocatalytic activity on the titanium substrate.

Titanium electrode classification

According to the chemical composition and main electrochemical properties of the coating, titanium electrodes can be roughly divided into the following three categories:

▲Ruthenium Coated Titanium Electrode

This type of electrode has low chlorine evolution overpotential and high oxygen evolution overpotential and is mainly used in various chlorine analysis occasions, such as the Chlor-alkali industry, cathodic protection, etc. This type of electrode coating includes the original ruthenium-titanium coating (Ru-Ti) and Ru-Ir-Ti, Ru-Co-Ti, Ru-Co-Sn-Ti, Ru-Sn-Ti, Ru-Si-Ti, Ru-Ti-Zr, Ru-Ti-La, Ru-Ti-Ce, and other coatings.

▲Non-ruthenium-coated titanium electrode

Ruthenium is a precious metal with a high price and limited reserves in nature. In order to reduce the amount of Ru or even completely replace Ru, a non-ruthenium-based coated titanium electrode was developed. This type of electrode generally has a high oxygen evolution overpotential. More successful electrodes include tin-antimony-coated titanium electrodes, Co3O4 spinel-coated titanium electrodes, and palladium oxide-coated titanium electrodes.

▲Iridium Coated Titanium Electrode

In some electrolytic processes, such as electrolytic extraction of non-ferrous metals, electroplating industry, and electrochemical reduction to produce organic matter, etc., the design reaction of the anode is an oxygen evolution reaction, so it is hoped to develop an anode material with low oxygen evolution overpotential, iridium coating It is against this background that layered titanium electrodes were developed. Ir-Co, Ir-Ta, Ir-Sn, Ir-Ta-Co, Ir-Ru-Pd-Ti, and other coatings are examples of such electrode coatings. Among them, the Ir-Ta-coated titanium electrode is the most successful oxygen evolution electrode.

The preparation methods of titanium electrodes are as follows

■Thermal decomposition

The thermal decomposition method usually dissolves metal salt compounds in organic solvents or aqueous solutions, coats the solution on the titanium substrate, volatilizes the solvent by heating, and then sinters at high temperature to decompose and oxidize the salts to obtain an oxide coating. Coating methods include spraying, rolling or brushing. High levels of mechanization, suitability for large-scale industrial production, and a pleasant working environment characterize spraying and roller coating. The coating is relatively uniform, but the waste of coating liquid is relatively large. Brush coating is generally suitable for small-scale production. This method requires simple equipment and less loss of coating liquid, but the labor intensity is high, the working environment is poor, and the obtained coating is often not uniform enough. By carefully managing the coating formulation, it is simple to create multi-component oxide electrodes with high performance using the thermal decomposition approach.

■Sol-gel method

An new technique for creating coatings is the sol-gel approach, which is based on the colloid chemistry theory. It can prepare electrode coatings with ultrafine grains, which greatly increases the specific surface area of the electrode surface. In order to make titanium electrodes using this method, metal-organic compounds (such metal alkoxides) or inorganic compounds are often dispersed in solvents, active monomers are produced through hydrolysis, and the titanium electrodes are then prepared， and polymerize active monomers to form sols, and coat the sols on On the titanium substrate, the sol film is dried to obtain a gel film, and then sintered at a certain temperature to obtain a coating. Compared with the traditional thermal decomposition method, the electrode coating prepared by this method is uniform, the grain is finer, and there is almost no crack, which has attracted much attention in recent years.

■Electrodeposition

The electrodeposition method is used to prepare coated titanium electrodes. Generally, an insoluble electrode is used as an anode, and pretreated metal titanium is used as a cathode. It is electrolyzed in a solution containing corresponding metal ions, and the metal ions are deposited on the metal titanium cathode. After drying, then high temperature The coated titanium electrode is obtained by sintering. The coatings obtained by this method are usually relatively uniform and dense. The disadvantage of this method is that the process is complicated, and it is not easy to make a uniform large-area electrode.

■Sputtering method

The film prepared by the sputtering method is dense and has a strong bonding force with the substrate. However, this method needs to use special equipment, the preparation process is relatively complicated, and the mother liquor is wasted more, so it is not suitable for industrialized large-scale production.

Introduction to the production process

1. Choose TA1 type titanium base material, and make sure the surface of the plate is smooth and smooth, without deep scratches and incompleteness.

2. Apply mechanical processing to the chosen titanium substrate to shape and size it according to customer specifications.

3. Perform annealing and leveling treatment on the titanium substrate at a temperature >500°C. (To eliminate stress and ensure flatness.)

4. During the annealing and leveling treatment, a dense titanium oxide layer will be formed on the surface of the titanium substrate, and it will be polished mechanically or manually to make the surface have a metallic luster of titanium.

5. Pickle and corrode the titanium substrate using oxalic acid at a 10% concentration. Do this for many hours while the acid is just beginning to boil so that the titanium hydride's surface oxide layer is etched into the metal.

6. Configure a precious metal solution in a fair qualitative and quantitative way in accordance with the anode environment that the customer has applied.

7. Check that the pickling titanium base material is qualified, that is, the surface layer is a gray uniform pockmarked structure, and then carry out manual coating, sintering according to the set appropriate temperature, naturally cool after sintering out of the furnace, and apply the second coating when it cools to room temperature Squeeze, and so on, until more than 17 to 20 times to apply the configuration solution.

8. The life experiment test is conducted using the furnace test piece after the sintering of the aforementioned processed parts is complete. The test is then qualified and packaged for delivery.