Where the colour comes from
Zinc plating starts as a silver-grey zinc layer, then gets a chromate passivation dip that adds both colour and corrosion protection.
Modern work uses trivalent (Cr3+) chromate, free of hexavalent chromium (Cr6), per RoHS.
Colour chart and uses
- White/Blue — silvery, clean look; common for general indoor parts; baseline corrosion protection.
- Yellow/Rainbow — iridescent gold tint; thicker chromate; better protection than white.
- Yellow — deep gold; good protection; popular in automotive/hardware.
- Black — black finish; looks and protection; popular for decorative/electronics parts.
- Olive/Green — highest corrosion protection of the chromates; outdoor/military use.
How to choose
For corrosion priority, darker tints (yellow/rainbow/green/black) usually outlast white-blue.
For appearance or to match an assembly, choose by design.
For a measurable rating, specify the salt-spray hours you need and we select the chromate/thickness to suit.
FAQ
Does colour really indicate protection?+
It indicates a trend—darker chromates (yellow/green) usually protect better than white-blue—but confirm the real number with a salt-spray test.
Rainbow vs white zinc?+
They differ in chromate: rainbow has a thicker layer so it protects better and shows iridescence; white is cleaner but baseline.
Can I choose the colour?+
Yes—tell us the colour and protection level (salt-spray hours) and we set the process to match.
