Plating, anodizing, powder coating, passivation
Metal finishing services by finish and spec
Each finish below has its own page with typical thickness, the specs buyers call out, the base metals it suits and what to put on the drawing. When you know the finish, send one RFQ and we match it with up to 3 shops that run it.
Finish pages
Thickness and spec values are typical, not promised.
Zinc-nickel plating
Alloy plating with 12 to 15% nickel. The usual step up from plain zinc and a common cadmium replacement.
- Typical
- 5 to 15 µm
- Specs
- ASTM B841, AMS 2417
- On
- Steel, hardened steel with bake
Electroless nickel plating
Nickel-phosphorus deposit with even thickness in bores and threads. Phosphorus level sets hardness and corrosion.
- Typical
- 5 to 75 µm
- Specs
- ASTM B733, AMS 2404
- On
- Steel, aluminum, copper, stainless
Hard anodizing (Type III)
Thick, wear resistant oxide grown out of the aluminum. About half builds outward, half goes into the part.
- Typical
- 25 to 75 µm
- Specs
- MIL-PRF-8625 Type III
- On
- Aluminum
Powder coating
Thick, cured polymer finish over a conversion pretreatment. Color, gloss and outdoor durability in one coat.
- Typical
- 50 to 100 µm
- Specs
- Customer spec, AAMA 2603 to 2605
- On
- Steel, aluminum
Passivation of stainless steel
Acid treatment that removes free iron from machining. No build-up and no change in size.
- Typical
- No build-up
- Specs
- ASTM A967, AMS 2700
- On
- Stainless steel
Black oxide coating
Thin black conversion layer with oil or wax. Almost no change in size, mild indoor protection.
- Typical
- About 1 µm
- Specs
- MIL-DTL-13924
- On
- Steel, stainless
Every finish we match
The RFQ form covers more finishes than the pages above. Typical values for each, to help you write the drawing note.
| Finish | Common spec | Typical thickness | Base metal | Notes |
|---|---|---|---|---|
| Zinc plating | ASTM B633 | 5 to 25 µm | Carbon and alloy steel | Cheapest corrosion finish for steel. Clear, yellow or black passivate. |
| Zinc-nickel | ASTM B841, AMS 2417 | 5 to 15 µm | Steel, hardened steel with bake | Several times the salt spray life of plain zinc. Common cadmium replacement. |
| Electroless nickel | ASTM B733, AMS 2404 | 5 to 75 µm | Steel, aluminum, copper, stainless | Even thickness in bores and threads. Phosphorus level sets hardness and corrosion. |
| Hard chrome | AMS 2460 | 12 to 250 µm | Steel | Wear surfaces and rods, usually ground after plating. Fewer shops run it. |
| Anodize Type II | MIL-PRF-8625 Type II | 5 to 25 µm | Aluminum | Dyeable. Sealed for corrosion. Color varies by alloy. |
| Hard anodize Type III | MIL-PRF-8625 Type III | 25 to 75 µm | Aluminum | Wear resistant. About half builds outward, half penetrates. |
| Chem film | MIL-DTL-5541 | Under 1 µm | Aluminum | Keeps electrical conductivity. Good primer base. |
| Passivation | ASTM A967, AMS 2700 | No build-up | Stainless steel | Removes free iron left by machining. No dimensional change. |
| Black oxide | MIL-DTL-13924 | About 1 µm | Steel, stainless | Matte black with oil or wax. Mild indoor corrosion only. |
| Powder coat | Customer spec, AAMA 2603 to 2605 | 50 to 100 µm | Steel, aluminum | Thick and cosmetic. Mask threads, bores and ground points. |
| PVD | Customer spec | 1 to 5 µm | Hardened steel, stainless, titanium, carbide | Hard, thin coatings such as TiN, CrN and DLC. Runs at elevated temperature. |
Typical values, not promised. Hardened steel over 39 HRC needs a hydrogen embrittlement relief bake after any electroplating. See the relief bake guide.
Choosing between finishes
Start with the base metal and the one job the finish has to do: corrosion, wear, color, electrical contact or a tight fit. The self-check on the home page gives two or three finish families for each combination and the detail that usually goes wrong on the drawing.
One RFQ, up to 3 matched shops
Free for buyers. Send the drawing, base material, finish, spec and lot size. We reply within 24 business hours with matched shops or a clear no.
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