The thickness of the galvanized layer refers to the thickness of the galvanized layer on the surface of steel, and its thickness directly affects the corrosion resistance of steel.
Author: Marisa
The plating time in acid zinc electroplating varies depending on the desired thickness, current density, and bath composition. Generally:
Decorative plating (thin layer): 1–5 minutes
Standard protective coating: 10–30 minutes
Heavy-duty corrosion resistance: 30–60 minutes or longer
The thickness of the zinc layer depends on the application requirements:
| Application | Typical Thickness (μm) | Current Density (A/dm²) | Plating Time (min) |
|---|---|---|---|
| Decorative (e.g., jewelry, small parts) | 3–8 μm | 1–2 A/dm² | 5–15 min |
| General corrosion protection (e.g., fasteners, hardware) | 8–15 μm | 2–4 A/dm² | 15–30 min |
| Heavy-duty protection (e.g., automotive, outdoor use) | 15–25 μm | 3–5 A/dm² | 30–60 min |
| Special high-thickness applications | 25–50+ μm | 4–6 A/dm² (with agitation) | 60+ min |
Current Density: Higher current increases deposition rate but may cause roughness or burning.
Bath Composition: Proper zinc ion concentration and additives improve efficiency.
Temperature: Optimal range (20–30°C) ensures stable plating speed.
Agitation: Helps achieve uniform thickness by reducing concentration polarization.
Passivation: Required for corrosion resistance (e.g., yellow/blue chromate, trivalent passivation).
Drying: Prevents white rust formation.
For precise control, use a thickness gauge (e.g., X-ray fluorescence or magnetic coating tester) to verify plating quality.