Reasons for the increase in plating resistance group and methods to improve the conductivity of the plating auxiliary anode
I. There are many reasons for the increase in impedance, mainly as follows:
1, anodic oxidation reaction over time, the oxide layer thickening passivation;
2, due to the contact with the converging copper row of titanium plate has a false contact or titanium plate surface high temperature passivation;
3, the plating solution conductive medium content is reduced;
4, anode breakdown, platinum layer and the substrate bonding force was destroyed;
5, the rectifier power supply and sink poor contact and so on.
When the plating tank impedance increases, the tank pressure will also rise, when the tank pressure exceeds 10V, should not continue to increase the current, but should be properly adjusted current, such as: current down 10%, while the plating time is extended by 10%.
II. Methods to improve the conductivity of plating auxiliary anode
1. remove the anode and keep it not dehydrated (i.e., do not dry), put in 5% hydrochloric acid, soak for 2 hours or longer according to the actual situation, use soft brush to clean the anode surface, pay attention not to scratch the anode surface coating. Oxide will be mostly cleaned off, if the effect is not ideal, repeat the above steps, after basic washing, rinse with tap water repeatedly, then rinse with deionized water to ensure that there is no fluoride ions, before reuse.
2. Observe whether there is breakdown phenomenon (coating shedding phenomenon) on both sides of the anode, if the surface corrosion is serious, the anode can not be used again, if one side is good, and the other side is slightly corroded, you can turn over the good side to use it, polish the titanium plate contacting with the copper rows to remove the passivation layer, adjust the concentration of the plating solution appropriately upward, and check whether the contacts of power supply lines are in good contact.
3. If it is inconvenient to deal with it by yourself, you can contact the titanium anode manufacturer to return it for repairing and coating to save the material cost;
4. After the anode stops using, it is good to clean it with deionized water and take out the plating tank, and put it into the deionized water (or pure water) tank separately for storage to prevent drying, which is conducive to the protection of platinum-coated titanium electrode service life.