|
Coating/Plating
|
For use With
|
Degree of Corrosion
or Finish Resistance
|
Characteristics
|
| Rust inhibitors |
All metals |
Varies with type |
Oils, greases etc. Vary in color and film thickness. Usually applied to black oxide finishes. Used to protect parts in transit & temporary storage. |
| Zinc, electroplated |
All metals |
Very good |
Blue to blue-white gray color. |
| Cadmium, electroplated |
Most metals |
Excellent |
Bright silver-gray, dull gray or black finish. Particularly effective corrosion protection in marine applications. Used for decorative purposes. Lubricate well. |
| Clear chromate finish |
Zinc & cadmium |
Very good to excellent |
Clear bright or iridescent chemical conversion plated parts coating applied to plated parts to enhance corrosion protection, coloring & paint bonding. |
| Dichromate |
Zinc & cadmium |
Very good to excellent |
Yellow, brown, green or iridescent colored plated parts coating. Same as clear chromate. |
| Color chromate finish |
Zinc & cadmium |
Very good to excellent |
Olive drab, blue, gold, bronze, etc. Same as plated parts clear chromate. |
| Zinc or Manganese |
Steel |
Good |
Black in color. Added protection when oiled Phosphate with a non-drying petroleum oil containing corrosion inhibitors. Lubricate well |
| Color phosphate coatings |
Steel |
Superior to regular |
Chemically produced color coating. Available phosphate & oiled surfaces in blue, green, red, purple, etc. |
| Hot-dip zinc |
All metals |
Very good |
Gives maximum corrosion protection. Dull grayish color. Necessitates thread size adjustments to permit ease of assembly |
| Mechanically deposited |
Steel |
Very good |
Dull gray, smooth finish. Corrosion protection zinc depends on coating thickness. Good coverage in recesses & thread roots. |
| Tin, electroplated |
All metals |
Excellent |
Silver-gray color. Excellent corrosion protection for parts in contact with food. |
| Silver, electroplated. |
All metals |
Excellent |
Decorative, expensive, excellent electrical conductor. |
| Chromium, electroplated |
Most metals |
Good |
Bright blue-white, lustrous finish. Has relatively hard surface. Used for decorative purposes or to add wear resistance. |
| Copper, electroplated |
Most metals |
Fair |
Used for nickel & chromium plate undercoat. Can be blackened & relieved to obtain antique, statuary & venetian finishes. |
| Brass, electroplated, |
Steel, usually |
Fair |
Brass electroplated which is then lacquered. Recommended for indoor decorative use. |
| Bronze, electroplated, |
Steel, usually |
Fair |
Has color similar to 80% copper, 20% zinc alloy. Electroplated & then lacquered. Recommended only for indoor decorative use. |
| Bright nickel |
Most metals |
Indoor excellent. Outdoor |
Electroplated silver-colored finish good if thickness at least 0.0005 inches Used for appliances, hardware, etc. |
| Dull nickel |
Most metals |
Same as bright nickel |
Whitish cast. Can be obtained by mechanical surface finishing or a special plating bath. |
| Anodizing |
Aluminum |
Excellent |
Acid electrolytic treatment. Frosty-etched appearance. Hard oxide surface gives excellent protection. |