Cast Copper No.-1 Sulfate Copper Electroforming Additive

In copper sulfate electroforming solution, the current efficiency both at chthode and anode are close to 100%. For the fast depositing speed, simple components of tank liquid, easy maintenance and management, little pollution to the environment, this kind of solution is widely used in copper electroforming technology. If using Cast Copper No.-1 in that technology, the tank liquid will have good levelling performance and wide current density and operating temperature range. The electroformed coat will have good rigidity, tensile strength and extensibility.
I . Technological formula and operational conditions
CuSO4180～220g/lCast Copper No.－12～4 ml/l
H2SO455～70 g/lCurrent density1～6 A/dm2
Cl---20～80mg/lArea ratio between cathode and anode1: 1.5～2
Temperature10～40℃
Anodecopper with 0.035～0.075% of phosphorus
Stiring methodair stiringcontinuous circulatory filtration

II . Preparation of electroforming solution
1. Heat and dissolve needed amount of copper sulfate with pure water, add small amount of sulfuric acid (chemically pure reagent, the amount of which is about 10% of the needed amount) to prevent the hydrolysis of copper sulfate, add 0.5~1ml/l hydrogen peroxide solution (30%)keep stiring for half an hour, and then 1～2g/l powdery active carbon, keep stiring for half an hour, and place it until it becomes pellucid.
2. Filtrate the solution, add residual sulfuric acid, and add pure water to the needed volume.
3. Convert to reagent hydrochloric acid basing on the needed amount of Cl-, dilute it with pure water and equally add into tank liquid.
4. Equally add the needed additive into the tank liquid, stir it to uniform, and you can begin the normal production after the tank liquid is tested to be qualified.

Ⅲ. Influence of operating conditions
1. Current densitythe brightening current density will become smaller if the content of copper sulfate lowers and sulfuric acid heightens, and become larger if the temperature heightens. When the cathodic current density is too large, the brightness of electroformed coat will be bad, the consumption of additive will be fast, thenodular anddendritic electroformed coat will easily be formed and the anode will easily be passivated.
2.Maximal operative electric quantity of tank liquid: the operative electric quantity of tank liquid is very important to the stability of tank liquid. When the operative electric quantity is too large, the anode will easily be passivated, the resistance of tank liquid will be large, the brightness of electroforming piece will be nonuniform and bad, and the consumption of additive will be fast. Therefore, the maximal electric current of each tank liquid is 0.5Aand it is best to control the current between 0.2~0.3A.

Ⅳ. Maintenance of tank liquid
1. Analyze tank liquid once a week, and adjust the components of tank liquid in time.
2. Circularly filter the tank liquid, and keep the tank liquid clean.
3.Absorb the jar foot and clean the anode every week.
4. Avoid the accumulation of Cu+. Stir with clean air or add 0.1～0.2ml/l hydrogen peroxide solution (dilute with water basing on the amount of calculation, add it into the tank liquid and stir) each time. For sulfuric acid is needed to oxidize Cu+, it should be added to technological range in time.
5. Regularly scrub the poles and copper cook, to keep their good electric contact.
6. The additive should be added regularly and frequently with small amount. Referential consumption of additive is 60～80 ml/KAh.

Ⅴ. Influence and removal of impurity:
1. The electric potential of arsenic and antimonial impurity is close to that of copper, so those impurity will make the electroformed coat coarse and fragile, and produce black and brown stripes. Please electrolyze with high current, that means electrolyze with 10～15A/dm2 current density for 4～8 hours.
2.If decomposition products of Cu⁺ and organics are too much, you may add 1～2ml/l hydrogen peroxide solution, keep stiring half an hour, heat to 65～70℃, continue to keep stiring for 2 hours, and add 3～5g/l powdery active carbon, stir it, and place it over night, and then filter it. Analyze components of tank liquid, adjust to technological range, and add some additive. The normal production can begin after successful trial electroforming.

Ⅵ. Common faults and disposals: