GB/T 9791-2025 Active
GB/T 9791-2025 Metallic and other inorganic coatings—Chromate conversion coatings on zinc,cadmium,aluminium-zinc alloys and zinc-aluminium alloys—Test methods
Abstract
This document describes the testing methods for the following items:
—— The presence of colorless chromate conversion coatings;
—— Qualitative measurement of hexavalent chromium in colorless and colored chromate conversion coatings on zinc, cadmium, aluminum (55% Al, with an allowable range of 54% to 56%), zinc-aluminum (5% Al) alloys;
—— Total chromium content per unit area on zinc and cadmium;
—— Mass of chromate conversion coatings per unit area for colorless and colored coatings;
—— Adhesion of chromate conversion coatings;
—— Corrosion resistance of chromate conversion coatings.
This document is applicable to the following chromate conversion coatings:
—— Colorless and colored chromate conversion coatings produced by chemical or electrochemical methods, containing different proportions of trivalent and hexavalent chromium;
—— Chromate conversion coatings without any additional coating layers (e.g., oil films, water-based or solvent-based polymer films, or wax films).
General Product Information
| Document Type | National standards |
|---|---|
| Standard Status | Active |
| Standard Code | GB/T 9791-2025 |
| CCS | Material protection |
| ICS | Surface treatment |
| Implement Date | 2026-05-01 |