As a core technology in the field of metal surface treatment, electrolytic copper plating has been widely recognized for
its process maturity and industrial applicability. This article will analyze the key nodes of the whole process of electrolytic
copper plating from the technical principle to the production practice, and provide practitioners with a reference guide
with practical value.
Electrolytic copper plating technology principle and core value
Electrolytic copper plating is based on the principle of electrochemical deposition, under the action of DC electric field, the
electrolyte containing copper ions undergoes directional migration. The anode copper plate continues to dissolve and replenish
copper ions, and the cathode (substrate) surface forms a uniform and dense copper plating layer. Its technical advantages are
reflected in three aspects:
Precise controllability: By adjusting parameters such as current density, temperature, PH value, etc., precise control of any
thickness within the range of 0.5-50μm can be realized.
Substrate universality: applicable to a wide range of materials such as steel, aluminum alloy, plastic (after activation
treatment), including complex shaped workpieces.
Functional expansion: the base coating can carry multiple functions such as conductivity, corrosion prevention,
decoration, etc., providing an ideal base surface for subsequent processing.
Eight key control nodes for industrialized production
1. Base material pretreatment process
Mechanical polishing: use 800-2000 mesh sandpaper to polish step by step to eliminate surface scratches.
Chemical degreasing: alkaline solution (pH10-12) ultrasonic cleaning, time control in 3-5 minutes
Acid activation: 10% dilute sulfuric acid solution immersion for 30 seconds, to remove the oxide film
Water film test: to verify the hydrophilicity of the surface and to ensure that no oil remains.
2. Electrolyte system optimization
Examples of commonly used sulfate system formulations:
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Copper sulfate (CuSO4-5H2O) 180-220g/L
Sulfuric acid (H2SO4) 50-70g/L
Chloride ion (Cl-) 40-80mg/L
Brightness additive 3-5ml/L
Temperature control range: 20-30℃ (±1℃)
3. Power parameter setting
Cathode current density: 2-5A/dm²
Voltage range: 6-12V
Cathode area ratio: 1:1.5-2.0
Cycle commutation: forward and reverse time ratio recommended 3:1
Quality Defect Handling Manual
Case 1: Poor bonding of plated layer
Cause analysis: Incomplete pretreatment/current mutation/substrate passivation
Solution: Strengthen the oil removal process/adopt step-up voltage start/add pre-plated nickel layer.
Case 2: Fogging of plating layer
Cause analysis: additives ratio imbalance / insufficient chlorine ions / PH value shift
Solution: Adjust additives in Hull bath test/supplement hydrochloric acid/test PH automatic compensation system.
Case 3: Burnt edges
Cause analysis: High local current density/insufficient solution convection
Solution: add auxiliary anode/increase circulating pump speed to 3m/s.
Technology Innovation Trend and Application Expansion
Pulse plating technology: Adopt pulse waveform with 20%-50% duty cycle to improve deep plating capability by 30%.
Nano-composite plating layer: add 5-50nm Al2O3 particles, hardness up to HV220
Environmentally friendly process: breakthrough in cyanide-free copper plating system, reducing wastewater treatment cost by 60%.
Intelligent control: introduction of IoT sensors to realize online monitoring of plating thickness (accuracy ±0.1μm)
In the field of 5G communication, high-frequency circuit boards are selected to be plated with copper thickness of
0.8μm±0.05μm and roughness Ra<0.3μm; new energy vehicle battery connectors adopt double-layer copper plating
structure, with the bottom layer of 5μm dense copper + 10μm high-conductivity copper, and resistivity reduced by 18%.
Key points of safety production specification
Equipped with leakage protection three-level joint control system
Acid mist collection tower purification efficiency must be >95%.
Wastewater classification collection device must contain chromium, nickel special piping
Operators need to hold a special operating license for electroplating operations
Conclusion: Electrolytic copper plating technology is evolving deeply in the direction of precision, intelligence and environmental
protection. Mastering the control logic of core process parameters and establishing a perfect quality control system will become
the key to build competitive advantages in the field of surface treatment. It is recommended that practitioners continue to pay
attention to the development of new additives and the integration of intelligent control systems in order to cope with the
increasingly stringent requirements of industrial manufacturing.