On 16th September 2015, the International Electrotechnical Commission (IEC) issued a new test method IEC 62321-7-1:2015, which describes a boiling water extraction procedure intended to provide a qualitative determination of the presence of hexavalent chromium (Cr(VI)) in colourless and coloured corrosion-protection coatings on metallic samples.
According to IEC 62321-7-1:2015，when Cr(VI) in a sample is detected below 0,10 μg/cm2, the sample is considered to be negative for Cr(VI). Since Cr(VI) may not be uniformly distributed in the coating even within the same sample batch, a “grey zone” between 0,10 μg/cm2 and 0,13 μg/cm2 has been established as “inconclusive” to reduce inconsistent results due to unavoidable coating variations. In this case, additional testing may be necessary to confirm the presence of Cr(VI). When Cr(VI) is detected above 0,13 μg/cm2, the sample is considered to be positive for the presence of Cr(VI) in the coating layer.
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IEC 62321-7-1:2015 Presence of Cr(VI) in colourless and coloured corrosion-protected coatings on metals by the colorimetric method |
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Test result(μg/cm2) |
<0.10 |
0.10~0.13 |
>0.13 |
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Conclusion |
negative |
inconclusive |
positive |
IEC 62321-7-1:2015 supersedes partial content of the previous IEC 62321:2008. IEC 62321 documents will gradually take the correspondent clauses of IEC 62321:2008. Currently, IEC 62321-1, -2, -3-1, -3-2, -4, -5, -6, -7-1 are issued (eight parts in total). Unpublished contents in IEC 62321:2008 as a part shall be valid before all parts are issued separately.