GB/T 9791-2025 Active National standards

GB/T 9791-2025 Metallic and other inorganic coatings—Chromate conversion coatings on zinc,cadmium,aluminium-zinc alloys and zinc-aluminium alloys—Test methods

Publish Date: 2025-10-31 Implement Date: 2026-05-01 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: GB/T 9791-2025

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Material protection

ICS Name: Surface treatment

Publish Date: 2025-10-31

Implement Date: 2026-05-01

Pages: 16 pages

Scope

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).