REACH - Applications for authorisation AFA042-01 - Multiple Cr(VI)

Overview

Public consultation on alternatives

Reference: AFA042-01 

Applicant: Brenntag UK Ltd

Application type: Review Report 

Substance name: 

• Sodium dichromate (SD)
  • EC Number: 234-190-3
  • CAS Number: 10588-01-9

• Potassium dichromate (PD)
  • EC Number: 231-906-6  
  • CAS Number: 7778-50-9  

Proposed use: Passivation of (non-Al) metallic coatings using sodium dichromate or potassium dichromate in aerospace and defence industry and its supply chains

Broad information on use applied for (conditions of use and function): 

This use covers passivation of non-aluminium metallic coatings using sodium dichromate and/or potassium dichromate in the aerospace and defence industry and its supply chains where any of the following key functions are required: corrosion resistance (and active corrosion inhibition), chemical resistance, adhesion to subsequent layer, layer thickness, temperature resistance, electrical resistivity, and pre-treatment compatibility.

When the passivation process is applied to a metallic coating it produces a superficial layer containing a compound of the substrate metal and elements from the processing solution. In this process, Cr(VI) containing solution is applied on the non-aluminium coating forming a passive protective layer on the surface of the non-aluminium metallic coating. The level of protection is proportional to the thickness of the passivation layer.

The applicant has identified a shortlist of potentially suitable alternatives. Due to the complexity of design challenges, performance requirements, safety requirements and regulatory controls that must be tested for each listed alternative, and the need for industrial implementation in the whole supply chain, the applicant is seeking a review period of 12 years. 

This applied for use involves the continued use of sodium dichromate or potassium dichromate across approximately 30 sites in Great Britain.

List of descriptors: 

• Sector of end use (SU): 0: Other: Aerospace and defence industry and its supply chains 
• Environmental release category (ERC): 5  
• Process category (PROC): 0, 5, 8b, 9, 10, 13, 15, 21, 24, 28 
• Product category (PC): 14 
• Article category related to subsequent service life (AC): N/A 
• Technical Function: Other: Corrosion resistance (and active corrosion inhibition), chemical resistance, adhesion to subsequent layer, layer thickness, temperature resistance, electrical resistivity, and pre-treatment compatibility  

Annual tonnage used:

• Up to 10 tonnes per year for sodium dichromate
• Up to 5 tonnes per year for potassium dichromate

Review period requested: 12 years 

How to submit comments

Provide some basic information on possible alternative(s) in the online survey below but more detailed information should be provided in document(s) prepared using the commenting templates in the related section below. A “public version” should always be completed and will be published after the consultation has closed. If you want to include confidential information in your submission, please additionally complete a “confidential version” and submit both versions as attachments.

The consultation lasts for 8 weeks (unless otherwise specified) and closes at 23:59 London time (BST).