GB/T 39560.701-2020 Active National standards

GB/T 39560.701-2020 Determination of certain substances in electrical and electronic products—Part 7-1:Hexavalent chromium—Presence of hexavalent chromium[Cr(VI)]in colourless and coloured corrosion-protected coatings on metals by the colorimetric method

Publish Date: 2020-12-14 Implement Date: 2021-07-01 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 39560.701-2020

Standard Type: National standards

Standard Status: Active

is_force_gb: no

CCS Name: Electronic components

ICS Name: Electronic components comprehensive

Publish Date: 2020-12-14

Implement Date: 2021-07-01

Pages: 15 pages

Scope

This part of GB/T 39560 specifies a boiling water extraction method for the qualitative determination of hexavalent chromium in colorless and colored anti-corrosion coatings on metal samples.
Due to its high reactivity, the content of hexavalent chromium in anti-corrosion coatings can change significantly over time and under different storage conditions. Since the storage conditions of samples before submission are often unknown or unavailable, the presence of hexavalent chromium in the coating can only be determined based on the detected content at the time of testing. When testing newly plated samples, a waiting period of at least 5 days (after the electroplating process) is required to ensure that the coating has stabilized. During this waiting period, the oxidation of trivalent chromium to hexavalent chromium may occur.
The presence of hexavalent chromium is determined by the mass of hexavalent chromium per unit area of the coating, expressed in micrograms per square centimeter (μg/cm2). This method is preferred because it is often difficult to accurately measure the mass of anti-corrosion coatings after product production. From the perspective of coating technology, the industry trend is either to use hexavalent chromium-free chemicals, with minimal or no hexavalent chromium present, or to use traditional hexavalent chromium-containing chemicals with significant hexavalent chromium content that can be reliably detected. Given these industry changes, determining the presence of hexavalent chromium is sufficient for regulatory compliance purposes.
In this process, if the detected hexavalent chromium in the sample is below the LOQ (limit of quantification) of 0.10 μg/cm2, the sample is considered negative for hexavalent chromium. Since hexavalent chromium may not be evenly distributed across the coating in the same batch of samples, the "gray zone" between 0.10 μg/cm2 and 0.13 μg/cm2 is defined as "inconclusive" to reduce inconsistent results due