Letter 30087

Percent hexavalent chrome in our parts? [Connecticut] 

++++

We manufacture parts that are plated with zinc & yellow chromate to Spec QQZ325, Type 2, Class 2. I have been asked to report on the percent of hexavalent chrome in our parts and have been unable to get this information from our plating vendors. Where can I get the total weight per volume of this plating and the percentage fo the plating that is hexavalent chrome?

Timothy Dahlstrom
Manufacturing - Torrington, Connecticut, USA

In an article titled 'Replacing hexavalent chromium' by Paul Wynn published by a few trade magazines on both sides of the Atlantic (do a web search and you'll find it) it is stated that 'electrozinc and yellow CRVI has a film weight of 12 mg/dm2, of which 70% is identified as CrVI'.

Dougie Lightfoot
- Scotland

Dear sir,

I don't know that spec, our company works with VW specs (VW 13750), but typical values for content of CrVI in the yellow passivation layer are 80-220 mg/m^2 (thickness: 250-500 nm). For further information, you can contact IMDS system (www.mdsystem.com). In case you have access to it, search for "Chromate film yellow Zn/ZnFe/ZnNi".

Best regards.

Francisco Ferro
- Lisboa, Portugal

I want to answer or follow-up on this subject publicly (in non-commercial fashion).

 

My company is a supporting advertiser at finishing.com and we want the contact information to reach the inquirer privately.

 

I want to post a new question or inquiry of my own on a different subject.