ASTM B841
Standard Specification for Electrodeposited Coatings of Zinc Nickel Alloy Deposits
Specifies electrodeposited zinc-nickel alloy coatings on metals with conversion-coating and thickness designations.
What ASTM B841 specifies
ASTM B841 covers aqueous electroplated zinc-nickel alloy deposits. Current procurement uses nickel-composition class, supplementary-treatment type, and thickness grade. Historical and recent editions identify Class 1 as 5–12% nickel, with prior 2018 text also recognizing a 12–16% Class 2; Types A through D identify colorless, yellow, bronze, and black conversion coatings, and Type E adds an organic topcoat. Grades 5, 8, and 10 mean minimum thicknesses of 5, 8, and 10 µm. Buyers should state hexavalent or non-hexavalent conversion chemistry, color, corrosion requirement, significant surfaces, and hydrogen-relief treatment.
ASTM B841 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Thickness | Requirement / test |
|---|---|---|---|
Class 1 | Zinc-nickel deposit with 5–12 mass % nickel. | — | Nickel composition. |
Types A–E | A colorless, B yellow, C bronze, D black conversion coating; E adds organic topcoat to one of these. | — | Appearance and corrosion resistance. |
Grade 5 | Minimum 5 µm zinc-nickel. | ≥ 5 µm ≥ 0.2 mil | Local thickness. |
Grade 8 | Minimum 8 µm zinc-nickel. | ≥ 8 µm ≥ 0.31 mil | Local thickness. |
Grade 10 | Minimum 10 µm zinc-nickel. | ≥ 10 µm ≥ 0.39 mil | Local thickness. |
Tests and the drawing call-out
Tests the document imposes
- Nickel alloy composition
- Coating thickness
- Adhesion and visual quality
- ASTM B117 corrosion resistance by type and grade
- Hydrogen-embrittlement relief for susceptible steel
How to cite it
Drawing call-out
ZINC-NICKEL PLATE PER ASTM B841, CLASS <CLASS>, GRADE <5|8|10>, TYPE <A|B|C|D|E><HEXAVALENT STATUS>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
Finishes specified to ASTM B841
ASTM B841 — frequently asked
What does Grade 8 mean?
It requires at least 8 µm of zinc-nickel on significant surfaces. Grade is independent of conversion-coating color.
What is Type E?
Type E is one of the conversion-coating colors with an added organic topcoat. The underlying color and chromium chemistry should still be identified.
Is Class 2 still present in B841-26?
The 2018 edition introduced 12–16% nickel as Class 2, but available 2026 public summaries describe only Class 1. Confirm the purchased 2026 text before ordering Class 2.
ASTM B841 is copyrighted by ASTM International. This page explains the document so a drawing can be read; it does not reproduce the standard. Purchase the current edition from the publisher. Official source ↗