Zinc alloy plating barrel plating alkaline copper method

Tungsten eletrod the various parameters of alkaline copper plating analysis, a method for controlling alkaline copper.
Zinc alloy plating barrel plating process, the cyanide alkaline copper plating is a top priority throughout the process. A zinc alloy electroplating factory master site control levels mainly reflected the level of alkaline copper he controlled, the author based on his many years of practice, a little zinc alloy plating few remarks:
Cuprous cyanide: I believe that the cuprous cyanide should be controlled at 50-100g / l between the more appropriate cuprous high content of copper speed, high production efficiency, but cuprous cyanide above 100, the problem is increased significantly, increasing the chance of blistering lot. Cuprous cyanide is too low, the plating speed is slow and inefficient.
However, iron is generally not recommended alkaline copper backing exceed 30g / salt is too high because the main impact force to fight the underlying collection.
Sodium: as complexing agent, sodium cyanide and cuprous cyanide recommended to maintain a certain percentage, as required complex 1 g sodium 1.1 g of cuprous cyanide. We produce remains a factor, that is the total amount of sodium cyanide = 1.38 × total amount of cuprous cyanide. Then the free cyanide content = (1.38-1.1) × cuprous cyanide.
Free cyanide content control in this range, the production is generally more normal production of free cyanide control (0.25-0.3) × cuprous cyanide are higher than normal, to ensure that the copper dissolution.
Free cyanide is too high, poor brightness of copper, hydrogen seriously, the current efficiency is low, the workshop heavy odor.
Free cyanide is too low, the lower zone go potentiometer, easy blistering, severe anode passivation, liquid blue green.
Tartrate: mainly active anode, the coating is more delicate, with an auxiliary complexing properties by adding the amount of 25-30.
pH: zinc alloy plating barrel plating process pH is critical, appropriate range 5-12. pH value is normal or not judged plating solution is an important indicator. Electroplating master site should always pay attention!
Electroplating process will generally increase in pH. Then plating solution in a normal state. When the pH in the electroplating process fall down, indicating anodized in an abnormal state, that anode passivation.
Cyanide copper anode reaction is twofold: First, the copper dissolution; another anodic oxygen evolution reaction; 2OH - 2e = O2 ↑ +2 H +, so anodic oxygen evolution down the free hydrogen ions, resulting in decrease in pH.
When the pH drops in production should immediately think of anodic dissolution is not normal, it should take immediate steps to change the status quo. Otherwise anode passivation, the following reaction;
2NaCN +2 H2O +2 NaOH + O2 = 2Na2CO3 +2 NH3 ↑
Namely carbonates increases, and is accompanied by ammonia production.
Carbonates cyanide plating bath, a small amount is beneficial, since it is the role of the conductive light effect. Newly opened cyanide plating bath are generally required to add a small amount of carbonate to increase the conductivity.
However, more than 70 or more carbonates, the apparent effects, coating loose, high porosity. Plated copper plating sometimes 2-3 hours after the test acid or not, bubbling, Konghao many human and wit. Then the coating is not thick enough, but the coating has pores. One to the subsequent acid-nickel plating, zinc will rot out, causing nickel-black.
Then there are the anode surface layer of dense gray membrane affect anodic dissolution, if not immediately take measures to change the status quo, the anode area reduction, anode passivation will worsen. I have witnessed too many tasks factory because copper cylinder is not normal, production yields can not get out, but he kept the consumption of copper, nickel and black cylinder, continuous reaction! A plant which cylinder is not normal! Customers very satisfied! Month down the loss of hundreds of thousands!
Jiaxing Dong Xin Surface Treatment Material Co., Ltd. in accordance with its principles of the invention anodized anode activator activation anode has a special ingredient, can solve the problem of anode passivation. At the same time can quickly remove carbonates, without affecting production. Compared to conventional treatment with lime only save time with better results. A potion to give up almost two hours to restore the state to the new feature. As long as proper control, rarely fill cuprous cyanide. Sodium cyanide and brightener can only complement. Very stable.
pH is too high, more than 12.5, because of alkaline copper zinc alloy plating bath will not be free of zinc impurities, then easy to make plating yellow. If the case temperature is high, the plating is easily blistering.