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Adopted opinions and previous consultations on applications for authorisation

Adopted opinions and previous consultations on applications for authorisation


This page provides further information on the applications for authorisation or review reports, which have undergone public consultation. The applications for authorisation are in the opinion development phase until the final opinions of the Committees for Risk Assessment and Socio-economic Analysis have been adopted and sent to the European Commission. The European Commission's decision-making process can be followed through the comitology register, where further information is published about the REACH Committee's past and upcoming meetings.

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Substance Details

Chromium trioxide
EC Number
CAS Number
Entry Nr in Annex XIV
Use name
Functional chrome plating of piston rods for automotive and rail applications
Broad information on use applied for (conditions of use and function)
Chromium trioxide is applied in functional chrome plating for the surface treatment of non-alloyed and low-alloyed steel piston rods used in varying sizes in damper systems of passenger (e.g. cars), commercial (e.g. trucks) and rail vehicles (e.g. trains). The piston rod is the load carrying and central component part of the damper unit (shock absorber and/or levelling system) which is part of a vehicle chassis. Unrestricted functionality of a chassis and all its components is mandatory. As a wheel guiding element, piston rods represent an important safety relevant component part of all kinds of vehicles and have to resist high bending forces through the whole vehicle lifetime. The process of functional chrome plating is conducted by immersing piston rods (non-alloyed and low-alloyed steels) in water based chromium trioxide containing baths to electrochemically deposit a metallic chrome layer. Functional chrome plating is a well-known industrialized process involving the recirculation of treatment solutions in a closed loop, high throughput of parts and low process temperatures (to ensure that the base material is not degraded). In case of piston rods, also the pre-treatment step etching (surface activation) includes the use of chromium trioxide. However, the resulting coating on the finished product is entirely free from hexavalent chromium.

The result of the functional chrome plating process is a metallic chrome coating, which provides a range of desired properties to the finished piston rods. This metallic chrome coating provides the article with the following essential functionalities:

  • excellent tribological properties such as high mechanical and wear resistance, hardness and a low coefficient of friction leading to unrestricted functionality over the required vehicle life time
  • excellent corrosion resistance
  • good machinability (related to post-processing grinding & polishing).
The pre-treatment with chromium trioxide can be applied to all kinds of piston rod base materials and adequately prepares the material for the subsequent coating by removing undesired residues from the surface. The etch rate is well-defined and adjustable, so constant quality of the pre-treatment process can be assured. Additionally, the pre-treatment chemistry is fully compatible with the main process. The entire process is specified for automotive applications where this combination of performance characteristics is critical. All requirements apply to piston rods for damper systems in current production as well as for spare parts.

Annual tonnage used: >100 tonnes
Review period requested: 21 years
Use applied for number in application for authorisation
Broad information on use applied for (Use descriptor system)
Sector of end use (SU): 0: Other: Automotive
Environmental release category (ERC): 6b
Process category (PROC): 1, 2, 8b, 13, 28
Product category (PC): 14
Article category related to subsequent service life (AC): no
Technical Function: Plating agent, Etching agent, Corrosion inhibitor
Summary table of RMMs and OCs (non confidential)
Section 9 and 10 of the CSR (original and updated, if available) (non confidential)
Analysis of Alternatives (non confidential report)
Substitution Plan (non confidential summary)
Socio-Economic Analysis (non confidential report)
Joint Analysis of Alternatives and Socio-Economic Analysis (non confidential report)
Explanatory note
Additional information
ZF Friedrichshafen AG
Application type
Commission decided
Other consultations on the same/ similar use
Comments submitted to date
Response to comments by applicant
Responses to RAC and SEAC requests by Applicant(s) (non confidential)
Compiled RAC and SEAC opinions
Minority positions
Adopted commission decision (OJ summary)
Authorisation decision

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