Chromating
化学转化膜
RoHS-compliant clear and yellow chromate coatings over zinc or aluminium to maximise corrosion resistance.
Chromating (chromate conversion coating) is a chemical treatment applied to zinc-plated steel, aluminium, magnesium, and cadmium surfaces to significantly improve corrosion resistance and paint adhesion. The process creates a thin, adherent conversion layer that acts as a barrier against moisture and corrosive ions.
At Active Treatment, we offer both clear (transparent) and yellow chromate passivation using trivalent chromium (Cr3+), ensuring full RoHS and REACH compliance. Yellow chromate provides superior corrosion resistance, while clear chromate gives a bright, mirror-like silver finish.
Chromating is routinely applied as a final step after zinc plating on fasteners, brackets, and structural components for the electronics, automotive, and construction sectors.
Key Benefits
- Greatly improved salt-spray corrosion resistance
- Excellent paint adhesion base
- Self-healing effect on minor surface damage
- RoHS compliant trivalent chromate
- Thin coating — negligible dimensional impact
Specifications
| Substrate | Zinc-plated steel, aluminium, magnesium |
|---|---|
| Thickness | 0.05–0.5 µm |
| Chromate type | Trivalent Cr3+ (RoHS compliant) |
| Salt spray (zinc + clear chromate) | 72–120 hours |
| Salt spray (zinc + yellow chromate) | 120–240 hours |
Frequently Asked Questions
What is chromating?
Chromating is a chemical conversion process that forms a thin protective film on metal — most commonly zinc-plated steel and aluminium — to improve corrosion resistance and paint adhesion. At Active Treatment in Singapore we apply RoHS-compliant trivalent (Cr3+) clear and yellow chromate finishes.
What is chromate conversion coating?
Chromate conversion coating is the technical name for chromating. Rather than depositing a separate plated layer, the chemical conversion coating reacts with the metal surface to grow an integral protective film that seals zinc and aluminium against moisture, improves corrosion resistance, and provides an excellent base for paint or powder coating.
Why is chromating applied to aluminium?
Aluminium chromating creates a thin chemical conversion layer that protects bare aluminium from oxidation and corrosion while keeping the surface electrically conductive. It is also widely used as a primer and adhesion base before painting or powder coating, which is why aluminium chromating (Alodine/Iridite-type treatment) is common in electronics and aerospace.
Does chromating improve corrosion resistance?
Yes. Chromating significantly improves corrosion resistance: clear chromate over zinc typically achieves 72–120 hours of salt-spray protection and yellow chromate 120–240+ hours, while the conversion layer has a mild self-healing effect on minor scratches. On aluminium it forms a durable barrier against oxidation.
What industries use chromating?
Chromating is used across the semiconductor and electronics, medical, automotive, construction, defence, and equipment manufacturing industries. In Singapore, Active Treatment applies chromate conversion coating to fasteners, brackets, enclosures, and aluminium components for these sectors.
Request a Quote
Contact Active Treatment Pte Ltd in Singapore for Chromating. Call +65 6352 9846 or email activetreatment88@yahoo.com.sg.