Acid zinc plating solution is a special liquid for chemical zinc plating, which is suitable for zinc plating on all metal surfaces, including iron, zinc alloy and copper alloy. The electrodeposited coating of acid zinc plating solution is metallic zinc.
Acid zinc plating solution is a special liquid for chemical zinc plating, which is suitable for zinc plating on all metal surfaces, including iron, zinc alloy and copper alloy. The electrodeposited coating of acid zinc plating solution is metallic zinc.
The acid zinc plating bath typically consists of the following key components:
| Component | Function | Concentration Range | Remarks |
|---|---|---|---|
| Zinc Sulfate (ZnSO₄·7H₂O) | Provides zinc ions for deposition | 200–400 g/L | Primary source of Zn²⁺ |
| Sodium Chloride (NaCl) or Potassium Chloride (KCl) | Improves conductivity | 15–30 g/L | Helps anode dissolution |
| Boric Acid (H₃BO₃) | pH buffer (stabilizes bath pH) | 20–30 g/L | Prevents pH fluctuations |
| Aluminum Sulfate (Al₂(SO₄)₃) | Grain refiner | 10–20 g/L | Smoother deposit |
| Additive Type | Example Compounds | Function | Dosage |
|---|---|---|---|
| Primary Brightener | Benzylidene acetone, Aromatic aldehydes | Enhances brightness | 0.1–0.5 g/L |
| Secondary Brightener | Polyethylene glycol (PEG), Nonionic surfactants | Improves leveling | 1–5 g/L |
| Wetting Agent | Sodium lauryl sulfate | Reduces pitting | 0.5–2 g/L |
| Parameter | Optimal Range | Control Importance |
|---|---|---|
| pH | 3.5–5.0 (adjust with H₂SO₄ or NaOH) | Affects deposition rate & quality |
| Temperature | 20–30°C | Higher temps increase speed but may reduce brightness |
| Current Density | 1–5 A/dm² | Higher current = faster plating but risk of burning |
| Agitation | Mild air/magnetic stirring | Ensures uniform thickness |
Filtration: Continuous filtration (5–10 μm) removes impurities.
Carbon Treatment: Periodic activated carbon treatment removes organic contaminants.
Anodes: Use high-purity zinc anodes (99.99%) to prevent impurities.
Analysis: Regular titration/ICP testing for Zn²⁺, pH, and additives.