| Finish | Color | Corrosion Resistance | Material | Characteristics |
|---|---|---|---|---|
| Black Nickel | Black | Very Good | All Metals | Generally used as a matching finish. |
| Cadmium | Silvery Gray | Very Good | All Metals | Not suggested unless absolutely necessary due to toxic chemical concerns |
| Chromate | Yellow, Olive Drab, Black, Blue White | Good | All Metals | A dipping process following the zinc/cad process increasing rust resistance. |
| Chromium | Bright Blue White | Very Good | All Metals | Bright lustrous finish used when ultimate beauty and appearance are desired. |
| Colored Dyes | Most any Color | Good | All Metals | A dipping process following zinc/cad process for matching or color coding |
| Copper | Copper | Fair | All Metals | Common undercoat for nickel or for decorative purposes |
| Dichromate Dip | Rainbow Cast | Good | All Metals | A dipping process following zinc/cad improving resistance to rust |
| Nickel | Silver | Very Good | All Metals | Hard, stable, often decorative finish |
| Oxide (Black) | Lustre Black | Fair | Ferrous andNon-ferrous | Chemical immersion that does not add to thickness. Good wearing qualities. |
| Passivating | Very Good | Stainless Steels | A nitric acid dip to remove foreign materials, brighten, and improve rust resistance | |
| Phos & Oil | Black | Very Good | All Metals | Commonly used on clip and clamp spring steel products and other automotive fasteners. |
| Zinc (Electro) | Blue White | Good | All Metals | Most popular finish combining good rust resistance, appearance, and economy |
Hydrogen Embrittlement
A real concern
Generally associated with high-strength fasteners, hydrogen embrittled parts can fail suddenly without warning.
Hydrogen is absorbed into (generally) high strength / high alloy products during the pre-plating, acid cleaning or descaling process, and is then trapped in the part during plating. If not properly relieved, the trapped hydrogen migrates to points of high stress concentration (under the head of fasteners, etc.) The pressure creates or extends existing cracks, ultimately causing catastrophic part failure.
Proper baking post plating (defined by ASTM F1941) is critical to help avoid hydrogen embrittlement, but unfortunately it is NOT a guarantee!
Request that your high strength electro-plated parts are tested post plating to help assure application conformance., or, better still, request a plating solution that is mechanically applied and void of hydrogen embrittlement susceptibilities.