Use in electrical and electronic equipment

• Author: Clemm, Christan; Löw, Clara; Baron, Yifaat; Moch, Katja; Möller, Martin; Köhler, Andreas R; Gensch, Carl-Otto; Deubzer, Otmar
• Pages: 18-20

RoHS Annex II Dossier, final

Nickel sulphate and nickel sulfamate

18

2. USE IN ELECTRICAL AND ELECTRONIC EQUIPMENT

Description of processes

The EEE specific uses of nickel sulphate and nickel sulfamate are in metal surface treatment in

electrolytic plating as well as electroless technologies. Within these plating processes, the use of

both nickel salts is explained to be an intermediate use resulting in inclusion into or onto a matrix.

The function and applications of the nickel layer is further explained below.

Nickel sulphate and nickel sulfamate are converted into nickel metal during the electrolytic

processes in surface treatment. The Nickel Institute27 describes the plating process as follows:

“Nickel sulfate and nickel sulfamate are soluble nickel salts. During the electrolytic

process in metal surface treatment, these nickel salts are dissolved in the electrolytic

bath into nickel 2+ions and a salt complex (e.g. SO42-). The nickel ions migrate to the

cathode where the nickel ions are deposited as nickel metal on the surface of relevant

parts that have to be plated. Electroless nickel plating is an auto-catalytic reaction.

Similar to electrolytic plating, nickel salts are dissolved and form nickel 2+ions and a salt

complex (e.g. SO42-). Unlike the electrolytic process, it is not necessary to pass an

electric current through the solution to form a deposit of nickel on the substrate.

Electroless nickel plating provides an even deposit regardless of the shape and form of

the workpiece. It is used as alternative process especially for non-conductive surfaces.”

As for the question on possible residues in the layer, the Carl Zeiss Jena GmbH in its stakeholder

contribution28 provided own measurements performed with energy dispersive X-ray spectroscopy,

which is used to test for impurities. The data includes measurements of an electroless plated nickel

layer, showing no residual nickel sulphate in the deposit, and of an electrolytically plated nickel

layer put of nickel sulfamate, also showing no nickel sulfamate in the deposit. The measurements

show that no residues remain after the treatment processes.

During the 2nd stakeholder consultation, Lynred (2019),29 a manufacturer of infrared imaging

detectors, stated that their suppliers communicate on the concentration of nickel sulfamate on the

items that “probably >0.1% on electroformed nickel screens and < 0,1% on the coatings of the

concerned components of cold fingers”. Lynred (2019) concluded that less than 100 g of nickel

sulfamate might be found in final products of a year. Thus, there are uncertainties as to residues in

the final product. However, this estimation will not further be taken into account.

27 Nickel Institute (2018): Contribution submitted on 15.06.2018 during the stakeholder consultation conducted from 20

April 2018 to 15 June 2018 by Oeko-Institut in the course of the study to support the review of the list of restricted

substances and to assess a new exemption request under RoHS 2 (Pack 15);

http://rohs.exemptions.oeko.info/fileadmin/user_upload/RoHS_Pack_15/1st_Consultation_Contributions/Contribution

_Nickel_Institute_Ni_20180608ROHS_Stakeholder_Consultation_FINAL_Comments.pdf, last viewed 18.06.2018

28 Carl Zeiss Jena GmbH (2018): Contribution submitted on 07.06.2018 during the stakeholder consultation conducted

from 20 April 2018 to 15 June 2018 by Oeko-Institut in the course of the study to support the review of the list of

restricted substances and to assess a new exemption request under RoHS 2 (Pack 15);

http://rohs.exemptions.oeko.info/fileadmin/user_upload/RoHS_Pack_15/1st_Consultation_Contributions/RoHS-

Pack15_Statement-CZJ_Ni-Compounds_final_signed_01062018.pdf, last viewed 18.06.2018

29 LYNRED (2019): Contribution submitted on 07.11.2019 during the stakeholder consultation conducted from 26

September 2019 to 07 November 2019 by Oeko-Institut in the course of the study to support the review of the list of

restricted substances and to assess a new exemption request under RoHS 2 (Pack 15);

https://rohs.exemptions.oeko.info/fileadmin/user_upload/RoHS_Pack_15/4th_Consultation/Contributions/contribution

_LYNRED_RoHS15_comments_Ni_20191107.pdf, last viewed 30.01.2020