Application of Titanium Anode in Electroplating
Rare precious metal oxide-coated titanium anode is made of precious metal iridium salt coated on titanium substrate and sintered at high temperature. It is widely used in electroplating (electroplating copper, nickel, cobalt, gold, zinc, etc.), electrolysis (electrolytic copper, nickel, palladium, rhodium, etc.) and other hydrometallurgical industries. The preparation and application of noble metal oxide-coated titanium anodes are quite mature, with a history of more than 40 years. Compared with the traditional platinum-plated electrode applied in alkaline copper, the advantages of titanium anode are as follows:
1. High current efficiency, excellent corrosion resistance, long service life of the anode, and can carry a high current density (up to 10000A/M2).
2. Energy saving: As we all know, the platinum-plated electrode is a high peroxygen (1.563V, relative to mercurous sulfate) electrode, while the noble metal oxide-coated titanium anode is a low oxygen evolution overpotential (1.385V relative to mercurous sulfate) Electrode, oxygen evolution is easier in the anode oxygen evolution zone. Therefore, during electrolysis, the cell pressure is also relatively low, which saves electricity. This phenomenon has been clearly manifested in the alkaline copper plating tank after copper foil treatment.
3. No pollution: Noble metal oxide coating Titanium anode coating is a ceramic oxide of noble metal iridium, which is a fairly stable oxide, almost insoluble in any acid and alkali, and the oxide coating is only 18~40μm , the overall coating oxide content is small. Therefore, the noble metal oxide-coated titanium anode will not pollute the plating solution, which is basically the same as the platinum-plated electrode.
4. High cost performance: In terms of reaching the same service life as platinum-plated electrodes (coating thickness of 3.5 μm), the price of noble metal oxide-coated titanium anodes is about 80% of that of platinum-plated electrodes. The noble metal oxide-coated titanium anode has better electrochemical stability in alkaline copper electroplating electrolyte, and at the same time it has excellent electrocatalytic activity and durability. From the cost analysis of the precious metal oxide-coated titanium anode and Pt electrode, it is obvious that the noble metal oxide-coated titanium anode is economical.
5. In the printed circuit board industry, the electroplating of copper needs to use pulse periodic reverse current (PPR). We know that in the environment containing chloride in the sulfuric acid system, the platinum layer will peel off after the platinum-plated titanium anode works for a period of time. However, the use of noble metal oxide-coated titanium anodes can effectively improve this phenomenon.
6. Low maintenance cost: Compared with traditional soluble electrodes (graphite and lead alloy electrodes), noble metal oxide-coated titanium anodes do not need to stop production frequently for cleaning, replenishing anodes, or frequently replacing anode bags and renewing anodes. Coating, so that the productivity is improved and the labor cost is reduced;
7. Under the same working conditions, the life of the noble metal oxide coated titanium anode depends on the working current density, temperature and bath composition.
