|
Finish |
Color |
For use on (material) |
Corrosion resistance |
Characteristics |
|
Zinc (electroplated)
|
White to blue grey
|
all metals
|
good
|
Most commonly used plating. Good rust resisting qualities, appearance and low cost. |
|
Cadmium (electroplated)
|
bright or dull silver grey
|
all metals
|
excellent
|
Superior rust resisting qualities. Used in marine and aviation applications. Relatively high cost and toxic to the environment. |
|
Chromate
|
yellow, olive drab,
black, blue/white
|
zinc & cadmium
plated parts
|
very good
|
A secondary dipping process after plating that increases corrosion resistance, adding color or brilliance. |
|
Dichromate
|
A combination of
yellow, brown, green or iridescent
|
zinc and cadmium
plated parts
|
very good
|
A secondary dip, same as chromate, only with rainbow appearance. |
|
Black Zinc
|
black
|
all metals
|
very good
|
Shining black appearance with good rust-resisting qualities. |
|
Black Oxide
|
black
|
ferrous metals and stainless steel
|
fair
|
A chemical discoloration which does not add to part thickness. Usually combined with an oil dip. Rust resistance comes from the oil only. |
|
Phosphate & oil
|
charcoal grey or black
|
steel
|
good
|
Zinc or manganese phosphate used with a rust-inhibiting oil dip. Low cost. |
|
Color Phosphate
|
blue, green, red,
purple, etc. |
steel
|
very good
|
Chemically produced coating superior to regular phosphate and oil. |
|
Iridite
|
olive drab, green, black, red, blue, bronze
|
all metals
|
good
|
Applied on top of zinc or cadmium plating as a die for color and additional corrosion protection. |
|
Nickel
|
silver
|
all metals
|
very good
|
Hard stable finish, relatively expensive and sometimes hard to apply. |
|
Chromium
|
bright blue/white
|
all metals
|
very good
|
Hard lustrous finish adds wear resistance and is very expensive. |
Hot Dip Zinc
(galvanizing)
|
dull grey
|
all metals
|
very good
|
Parts are dipped in pure zinc. Gives maximum corrosion protection. Adds a thick irregular coating. Size must be adjusted to allow for thickness of coat. |
|
Passivating
|
bright - etched
|
stainless steel
|
excellent
|
Parts are dipped in nitric acid which removes iron particles and brightens the finish. Produces a passive resistant finish. |
|
Anodizing
|
frosty - etched
|
aluminum
|
excellent
|
Acid dip produces a hard oxide surface. Can be color dipped after anodizing for preferred finish. |
