Professional Zinc Alloy Surface Finishing Solutions
Post-traitement pour le Revêtement en Système de Support
Post-Treatment: Passivation, E-Coating & Sealing
Plating gives the look — post-treatment decides how long it keeps it. The 6-step finishing system that takes salt spray from 24 h to 200+ h.
Conceptual illustration based on reference photographs; not test evidence.The 6-Step Post-Treatment Line
Every step after the plating bath, before the box
1DI Water Final Rinse
Deionized water removes residual salts that cause spotting and under-film corrosion. Tap water at this stage = future rust stains.
Key Parameters
Water quality: < 10 μS/cm
Stages: 3–5 counter-current
Conceptual illustration based on reference photographs; not test evidence.2Passivation / Sealing
Conversion coating that blocks corrosion initiation. Chromate for maximum protection, trivalent or organic for REACH compliance.
Key Parameters
Salt spray gain: +24 to +120 h
Options: Cr³⁺ / organic
3E-Coating (Electrophoretic)
Charged paint particles wrap every edge and recess. Clear, black or custom colors.
Key Parameters
Thickness: 15–25 μm
Cure: 160–180 °C, 20–30 min
4Controlled Drying
Forced-air drying below the water-spot threshold. Humidity-controlled tunnel, not open-air racks.
Key Parameters
Temp: 60–80 °C
Time: 10–15 min
5Final QC
D65 visual check, XRF thickness audit, cross-cut adhesion, and salt-spray coupon from every batch.
Key Parameters
Adhesion: ISO 2409
Sampling: per batch
6Anti-Tarnish Packaging
VCI bags or anti-tarnish tissue + desiccant. Correct packaging doubles shelf life before your customer even opens the box.
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Protection Levels Compared
Hours of salt spray per treatment stack
| Treatment Stack | Salt Spray | Look | Cost | Use Case |
|---|---|---|---|---|
| As-plated (bare) | 24–48 h | As-plated | — | Indoor, short shelf life |
| Chromate passivation | 48–96 h | Slight iridescence | Low | General hardware |
| Trivalent / organic sealer | 48–72 h | Clear, unchanged | Medium | EU / REACH orders |
| Clear e-coat | 96–200+ h | Glossy clear | High | Premium & outdoor |
| Color e-coat | 96–200+ h | Opaque color | High | Fashion statements |
| Lacquer on antique | 48–120 h | Satin, freezes patina | Medium | Antique finishes |
| Powder coating | 200–500+ h | Thick opaque | Very high | Industrial / marine |
📌 Post-Treatment Cheat Sheet
DI rinse quality< 10 μS/cm
E-coat thickness15–25 μm
E-coat cure160–180 °C / 20–30 min
Best outdoor stackNi + e-coat = 200+ h
REACH sealerCr³⁺ or organic
PackagingVCI + desiccant
💡 Compliance, HandledAll sealers and e-coats meet EU REACH and RoHS. Hexavalent-chromium-free passivation is our default. Compliance documents ship with your order for customs.
FAQ
Best stack for outdoor products?
Nickel base + clear e-coat (200+ h salt spray). Marine environment: ask for our duplex system with an extra seal layer.
Does passivation change the color?
Chromate adds slight iridescence; trivalent and organic sealers are visually clear. E-coat adds gloss and slightly deepens tone.
How long does e-coat last?
3–5 years indoors, 1–3 years outdoors. UV-stable formulations available for prolonged exposure.
Custom e-coat colors?
Black and white standard; custom tints at 500 L batch minimum plus a color-matching fee.
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