The color of Zinc plating comes from the passivation layer on top of zinc layer. Zinc itself is bright white metal color.
Below is a table to look at coorsion resistance of different colors of passivation layer.
| Passivation | thickness in nm | Corrosion Resistance hours NSS |
|
Blue(Cr3+) |
25-80 | 8-72 |
|
Iridescent(Cr3+) |
250-3500 | 72-120 |
|
Blue (Cr6+) |
25-80 | 8-24 |
|
Yellow(Cr6+) |
250-500 | 72-96 |
|
Oliv(Cr6+) |
1000-1500 | 300 |
|
Black(Cr6+) |
250-1000 | 150-300 |
***This is a general reference table, please check with your plating supplier for precise consultation.