Brown and Black

Red and Green

Yellow and Blue

Red and Black

Zinc and Cadmium plating

Nickel chrome plating

Powder coating

Phosphating

P₃ HO4

H₃ PO4

O₃ HP4

P4 HO₃

Convert to steel surface area

Plating on surface

Coating on surface

Masking of surface

Phosphoric acid solution

Hydrofloric acid solution

Hydrochloric solution

Chromic acid solution