Plastic electroplating-production skills of nickel-free white copper and tin electroplating.
Huizhou Boluo Tenglong Technology Co., Ltd. serves you wholeheartedly! Mainly engaged in plastic hydroelectroplating processing, with plastic injection molding processing, mold processing and so on!
Electroplating nickel-free white is one of the most widely used alloy coatings in electroplating factories. It has the advantages of good brightness of coating, low cost, no nickel in environmental protection, good decorative effect, corrosion resistance and suitable hardness, and can prevent the diffusion of the bottom metal to the surface layer and prevent the discoloration of metal coating. high tin nickel-free white, also known as silver mirror alloy or white copper tin, can be used as a substitute for silver and chromium. Copper accounts for 31% of the coating, tin accounts for 65%, and the rest is zinc. The appearance of this nickel-free white is similar to that of stainless steel, which is whiter than the nickel coating and can remain unchanged for a long time.
At present, there are many formulations used in the market:
Copper / tin / zinc / free potassium cyanide / brightener / pH12.4~12.9/ specific gravity / free cyanide specific gravity.
When doing this kind of plating, many colleagues will find that the color of the product is stable and white when the cylinder is opened, and it appears after some time of production, such as yellowing, blackening, poor displacement, dimming, fogging and so on. According to our team's on-site experience, we should sum up the faults in various electroplating factories from the systematic control:
1. If it is only used for decorative complexion, the cylinder is small, and if the color effect is high, it is best to use potassium cyanide instead of sodium cyanide, which increases the cost a little but can bring the stability of the plating bath and color.
two。. Most colleagues in the maintenance of this cylinder are not standard, see that there is a problem with the plating product, quickly pour sodium Stannate, cuprous and so on to adjust the slot "surgery"! This will lead to insufficient hydrolysis of drug complexation, and the composition is easy to be maladjusted. The color is naturally unstable. Here we will suggest: use potassium cyanide (imported grade) 280g/L, cuprous cyanide 143g/L, zinc oxide 8 grams of this ratio into copper water spare, and then use 300g sodium Stannate with 1L LJ- 29 complexing agent. The two medicines must be dissolved thoroughly and treated with activated carbon powder and added at 1:1 to ensure that the composition of the main salt is not out of balance. The standard operation of addition is the key to control this kind of plating.
3. The hanging plating temperature is controlled at 55-60 degrees. For roll plating, the temperature is not very high, and a small amount of pure tin plate anode can be added to the anode, which can reduce the addition of commercial sodium Stannate and reduce the cost.
4. The next step is to control the pH value of the plating bath, normally add a portion of copper water, and supplement 10 grams of potassium hydroxide. If the PH is too high, 30% phosphoric acid solution can be added; if the pH value of the plating solution is low, 25% potassium hydroxide solution can be added.
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