1. Iridium metal oxide coated titanium anodes (referred to as iridium MMO coated titanium anodes) need to be installed under the recommended electrolytic conditions.
2. Avoid contamination of the iridium MMO coating with oil or grease.
3. Iridium MMO coating is a ceramic coating with a porous surface and a large specific surface area, which has good electrochemical characteristics. Iridium MMO is very easy to be scratched or damaged when a hard object rubs or hits its surface: it is forbidden to place the surface of the Iridium MMO coating directly on the metal surface, and the hard surface should be covered with a protective paper or plastic film; Drag or slide the surface of the iridium MMO coating on any hard surface; if there is dirt or sediment on the surface of the iridium MMO coating, it is forbidden to clean it by any abrasive mechanical means. The use of wire brushes, sandpaper, sandpaper, or high-pressure water jets to clean the anode surface is prohibited.
4. When the titanium anode is removed from the plating tank, it should be rinsed with water immediately. To prevent acid corrosion, this is because the electrolyte dries on the surface of the coating and causes the acid concentration to increase.
5. Titanium anodes that need to be stored for a long period of time should be carefully packed with, for example, gas-filled plastic packaging materials to avoid scratching or falling dust on the surface of the iridium MMO coating.
6. Applying the iridium MMO coating to the active part of the titanium anode allows current to pass through the titanium anode coating surface to the electrolyte, while the uncoated titanium surface remains inert. If the small-area iridium MMO coating has mechanical damage, the titanium under the coating is in direct contact with the electrolyte, and the titanium anode can still continue to operate normally. This is because under anodizing conditions, the titanium surface forms a protective effect and has adhesion Oxide film.
7. Keep a little distance between the electrodes. An accidental short circuit between the titanium anode and the plated part can cause irreplaceable damage to the iridium MMO coating and can also damage the titanium substrate. If a serious short circuit occurs, the titanium anode will be completely destroyed.
8. As long as the titanium anode is immersed or directly in contact with the electrolyte, the titanium anode must be in an anodized state. If the titanium anode is not energized, a low positive voltage (residual voltage) can be added to the titanium anode. This only requires a voltage of 2 volts between the anode and the cathode, without the need for a power source and a large amount of current. Iridium MMO-coated titanium anodes must not be in a state where the electrodes are reversed at any time.
9. Trace impurities in the electrolyte, such as lead, iron and barium, should be controlled. This will not produce a large amount of anode deposits. Anode deposits can clog the titanium anode surface and cause uneven anode current distribution.
10. Organic additives are added to the electrolyte, and different additives will have different effects on the life of the titanium anode. The life of titanium anodes with iridium MMO coatings is significantly shortened especially due to the influence of additives or synthetic oxides.
11. Removal of precipitated hydrochloric acid on the surface of the titanium anode of the iridium MMO coating-this acid is very effective in removing various forms of rust precipitates and calcium-containing precipitates. Because of its reducing properties, it can only be operated at room temperature, and requires a diluted solution with a concentration of 37% hydrochloric acid that does not exceed 10% by volume. Because the titanium anode is still easily eroded by reducing acids like hydrochloric acid, the contact time between the anode and the anode should be kept to a minimum, generally 10 minutes. In order to reduce the degree of hydrochloric acid attack, before cleaning, 0.1% ferric chloride can be added to the cleaning solution. Note: After cleaning with hydrochloric acid, the titanium anode should be thoroughly washed with water, preferably immersed in water for at least 10 minutes. Citric acid — At 40–50 ° C, 5-10% citric acid can be used to remove iron-containing precipitates. It is still necessary to carefully rinse the anode with water after cleaning. Nitric acid —- Because nitric acid is an oxidizing acid, the iridium MMO coating is resistant to nitric acid at any temperature and concentration. However, because high concentration nitric acid has strong oxidizing property at high temperature, a titanium oxide film will be formed on the surface of the titanium substrate. The conductivity of this film is very poor. In nitric acid, nitric acid at low concentration and low temperature is very useful for removing a variety of precipitates that can form soluble nitrate, such as commercial nitric acid diluted below 10% and at room temperature.
