Number

437-EN

Section

General Section

Use

Abstract

Chromium trioxide was placed on the REACH Authorisation List in 2013 and its use has needed a specific authorisation in the EU since 2017. Instead of applying for an authorisation to further use the toxic substance in the electroplating of metal sanitary appliances it was decided to implement a trivalent chromium process and to eliminate chromium trioxide completely. In parallel, the nickel sublayer will be substituted by a white bronze.

Substituted substances

Alternative Substances

Reliability of information

Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication

Reason substitution

CMR
other toxic effects
ecotoxicity
physical hazards

Hazard Assessment

a) Human health:
Two substances of very high concern (Chromium trioxide and Nickel sulphate) are substituted with substances of lower toxicity. The established white bronze process is free of cyanide. A third substance of very high concern (Boric acid, Repr. 1B, H360FD) remains in the process, which is under regulatory evalution but has not been placed on the authorisation or restriction list at the time point when the case study was described. It is assumed that the overall risks for human health are reduced in comparison to the conventional procedure by avoiding the use of chromium trioxide and nickel sulphate.

b) Environment:
e.g. waste reduced/increased Nickel leaching from finished products is completely barred as Nickel is substituted. This is an important aspect as nickel leaching from sanitary armatures is considered to be a serious problem.

Description of Substitution

a) Motivation why to apply the alternative:
The authorisation applicable to the company expires in 2024. The high costs of reviewing the authorisation have provided the impetus to take the initiative. There are several alternative chromium III processes, but not with the required properties. In particular, it is not possible to do without nickel in all of these processes. Therefore, the chromium III process was optimised in close cooperation with a supplier.
Leaching of nickel from finished products is completely eliminated as nickel is replaced. This is an important aspect as nickel leaching from sanitary fittings is considered a serious problem.

b) Description of procedure or technology (including pre-/post-processing):
Chrome coating of brass is an electrochemical process. Parts are cleaned and degreased in several baths. A white bronze coat is deposited as substitute for the Nickel sub-coating. Chromium is electrolytically deposited on the sub-coat. Coated parts are passivated electrochemically and finally rinsed. The overall process is fully automated.

c) Way of application:
e.g. spraying, dipping, open/closed system etc. Parts are manually attached to racks. Racks are moved by a suspension crane into the galvanising plant where they are automatically transported along the bath line and dipped sequentially into the respective baths.

d) Risk management measures (technical, organizational and personal):
Access to the galvanising plant and to the baths is restricted to maintenance purposes only for specialised staff. Exhaust systems are installed at the upper edges of the baths. During maintenance and control personal protection equipment (protective coverall) is worn.

Advantage or Disadvantage of alternative

Aspect	Advantage/disadvantage to conventional process
Technical requirements	Corrosion resistance: as defined by EN 248 met by 90% Chemical resistance: OK Wear resistance: OK Adhesion between coating and substrate: OK Hardness: OK Sunlight resistance / UV resistance: met by 90% Temperature resistance: OK Coating thickness: OK Nickel leaching: OK (no Nickel in product) Geometry: no restriction Process temperature: no restriction
Implementation	Main obstacles: Larger required space (in implementation phase both processes are run in parallel) Missing essential knowledge for process conversion Missing customer / OEM specifications Competitive disadvantage as long as Cr(VI) process are still authorised
Operational expenses	Labour costs: + 5% (bath maintenance) Throughput: + 10% Process quality: identical Process costs: + 20% (chemicals) Material costs: + 20% (analytical instruments) Energy costs: + 5% Investments: 250,000 – 300,000 € (additional baths)
Other	The DVGW (German Association of the Gas and Water Industry) certificate of conformity has been available since 03/2022. The galvanized products comply with the limit value requirements from the Drinking Water Directive (TrinkwV 2001).

Supporting information:
Costs for ESH, OSH and waste disposal are potentially lower, but as the protection level will be upheld there is no change.

General economic aspects:
Service life of products is comparable to Cr(VI) coated products. Availability of materials is comparable to the Cr(VI)/Ni based process. The main advantage results from the combined transition from Cr(VI)/Ni to Cr(III)/CuSn and thus removal of Nickel from the end product. Bath temperature is lower for white bronze coating (30°C instead of 60°C) than for Nickel, and current is lower (~1 A instead of 4–6 A). Process speed improves remarkably as the manual activity of parts plugging can be dispensed with, which is necessary in the Cr(VI)/Ni-based process, in order to prevent nickel contaminations.

Case/substitution evaluation

The case story shows the substitution of two carcinogenic and sensitizing substances, chromium trioxide (Carc. 1A, H350; Skin Sens. 1, H317) and nickel sulphate (Carc. 1A, H350i; Skin Sens. 1, H317; Resp. Sens. 1, H334), in decorative chrome plating with a functional character. Instead of hexavalent chromium, trivalent chromium is used in the plating process; the final nickel layer is replaced by white brass.

Boric acid (Repr. 1B, H360FD) remains as SVHC in the presented alternative process. It is also used in the conventional plating process. The risks for man and environment are still under regulatory evaluation and remain unclear at the time of compiling the case story. Should information and evidence regarding this alternative or a safer and more sustainable alternative be present, please contact SUBSPORTplus.

In Germany, there are limit values for various metals, such as chromium, nickel and copper, according to the Drinking Water Ordinance. The limit values (e.g. for copper of 2 mg/l) can be complied with by the alternative.

Release of nickel compounds into the drinking water is known to occur from conventional plated products (see further information), if the products are not plugged before coating. However, plugging is time and cost intensive (personal communication). Substitution of the nickel sublayer is an alternative to increase drinking water safety and avoids the use of nickel sulphate in the first place.

For occupational safety and health: Substitution of two carcinogenic substances at the workplace is regarded as added value. If available, occupational exposure limits for the alternative substances used must be complied with as well. Adequate protection measures need to be taken into account at the workplace after a proper risk assessment.

State of implementation

Pilot study

Enterprise using the alternative

Heinrich Schulte GmbH & Co. KG Grünlandweg 11 58640 Iserlohn Tel.: 02371 - 90 90 0 Fax: 02371 - 90 90 99 https://www.heinrichschulte.com">https://www.heinrichschulte.com">https://www.heinrichschulte.com

Availability of Alternative

pilot study The nickel leaching test according to DIN EN 16058 (26-week test) was passed.

Type of information supplier

Producer / distributor

Contact

La Tecnogalvano S.R.L. Via Salvo D'Acquisto, 9/b 28076 Berzonno di Pogno (NO) Italy  https://latecnogalvano.it/en/galvanic-processes.html#innovativi

Further information

The factsheet describing the case study is available as a pdf download: to factsheet 437-EN

Publication source: author, company, institute, year

company

Date, reviewed

June 25, 2023