Plating, Coating | Used On | Degree of Corrosion or Finish Resistance | Characteristics |
Rust inhibitors | All metals | Varies with type | Oils, greases etc. Vary in color and film thick-ness. Usually applied to black oxide finishes. Used to protect parts in transit & temp. 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. High lubricity. |
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. Good lubricity. |
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 assemblability. |
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,statuari & 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 inchesUsed 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. |
Passivating | Stainless Steel | Excellent | Chemical treatment. Removes iron particles and produces a passive surface. |