Analysis of Alternatives (AoA) to Nickel containing chemicals used in decorative plating. Jens Tørsløv

Transcription

1 Analysis of Alternatives (AoA) to Nickel containing chemicals used in decorative plating Jens Tørsløv

2 Contents AoA methodology, approach developed during 3 studies AoA to nickel containing chemicals used in decorative plating Conclusions - learning

3 AoA Scope of assessment Sector level approach, i.e. a generic assessment Life cycle perspective: raw materials, plating process use and product R&D included based on available knowledge e.g. patents Only alternatives proved at an industrial scale are regarded as available techniques Economic assessment is only initial.

4 AoA Scope of assessment Identification of alternatives: Focus on technical - functional requirements (as required by the end-users). For plating this include at least: Corrosion resistance Wear resistance Hardness Decorative apperance, design

5 AoA methodology Technical suitability Technical requirements, e.g. hardness and durability Apperance and design requirements Risk reduction Risk assessment based on existing GES for the sector and DNEL/PNEC and OEL / EQS values Indication by RCR (without refinement) Ecomomic suitability (indicative) raw material prices, energy consume, production capacity

6 Case: AoA Nickel containing chemicals used in decorative plating

7 AoA Nickel containing chemicals used in decorative plating Aim has been to provide plating industry with a support document on alternatives to nickel in decorative plating Objectives: To identify potential alternatives to nickel used in decorative plating To analyse the suitability of the identified alternatives, including: Technically suitable Risk reduction Address general economic issues

8 Project organisation Initiator, Nickel Institute Working group: Lorenzo dalla Torre, Industria Galvanica Dalla Torre Ermanno & Figli S.p.A. Dr Paul Lansdell C Eng FIOM3 FIMF B.Sc., Operations Director Hart Materials Ltd Berthold Sessler, CETS, President Dave Elliott, Surface Engineering Association, Chief Executive Officer Denis Théry, UITS France, Délégué Général Henk de Man, Brandsma Metaalveredeling B.V. Herbert Breidenbach, ZVO Head of Environment Department Prof. Dr. Andreas Moebius, Enthone R&D Fellow, Enthone GmbH Consultant team: DHI supported by Mr. Jean-Jacques Duprat

9 Plating based on nickel containing chemicals Nickel prior to chromium plating Nickel prior to other metal finish (e.g. gold, silver, palladium). Plating using nickel alloys Tin-nickel 65/35 Nickel-iron alloy nickel-zinc Palladium-nickel 80/20

10 Plating types Nickel as sole coating Electroless nickel for plating on plastic (POP) Main features of electroplated nickel: Excellent adhesion and corrosion protection Levelling effect and support of brightness of the finishing layer wear resistance barrier to copper diffusion from substrate

11 Alternatives, selected examples White bronze (e.g. copper/zinc/tin 55/30/15) w. subcoat of bright acid copper Zinc + chromium (III) passivation + topcoat Copper + palladium or palladium alloys

12 Alternatives, technical evaluation selected examples Appearance Corrosion Hardness Uses Bright acid copper White bronze Whiter than nickel Passes sweat test but fails external accelerated tests Good hardness but due to low thickness, the wear resistance is low compared to nickel Indoor door handles, locks, fashion goods, trinkets, souvenirs Not suitable on tubes and pipes. Also POP Zinc + chromium (III) passivation + topcoat White blue. Like stainless but without shiny metallic aspect Outstanding corrosion protection Low hardness but outstanding wear resistance with self-healing effect Supermarket trolleys, window frame mechanisms, fasteners, hinges, small parts by bulk plating Copper + palladium or palladium alloys White colour slightly darker than white bronze Low corrosion resistance because of very thin layer but good in combination with further top precious metal layers Good hardness but low wear resistance because of very thin layer Jewellery, luxury items, watches, eye wear, medals

13 Process Substance RCR, long-term inhalation RCR, water environment Comments relevant to SVHC status Risk assessment - Alternative coating processes Bright acid copper White bronze Alkaline cyanidefree copper (prelayer) Copper hydroxide Cu(OH) 2 20 g/l 1-hydroxyethylidene- 1,1,-diphosphonic acid HEDP 180 g/l Copper sulphate CuSO 4, 5 H 2O 220 g/l sulphuric acid Copper cyanide CuCN 11 g/l Potassium stannate K 2Sn g/l Zinc cyanide Zn(CN) g/l Potassium cyanide KCN 45 g/l n.a Cyanides are highly acute

14 Process Substance RCR, long-term inhalation RCR, water environment Comments relevant to SVHC status Zinc chloride ZnCl 2 65 g/l Zinc + chromium (III) passivation + topcoat Potassium chloride KCl 220 g/l Boric acid H 3 BO 3 25 g/l Classified as Repr. 1B (CLP, Annex VI) Chromium (III) chloride CrCl 3 50 g/l Chromium (III) passivation Sodium nitrate NaNO g/l na na Cobalt nitrate Co(NO 3 ) 3 3 g/l Classified as Carc 1B and Repr 1B (CLP, Annex VI)

15 Plating type Uses Hazards and risk 1 Plating unit costs and other cost issues Bright acid copper, white bronze Zinc + chromium (III) passivation + topcoat Copper + palladium or palladium alloys Not suitable on tubes and pipes Supermarket trolleys, window frame mechanisms, fasteners, hinges, small parts by bulk plating Jewellery, luxury items, watches, eye wear, medals High RCR (environ) due to copper Can involve use of cobalt nitrate (Carc 1B and Repr 1B) and boric acid (Repr 1B) High RCR (environ) due to copper Copper + white bronze overall plating costs EUR 10/m 2 The global plating costs of zinc + chromium (III) passivation + a suitable topcoat are estimated to be EUR 3/m 2 Costs of palladium are very high and only feasible on luxury goods

16 Conclusions The present assessment is generic and more specific AoA need be based on specific requriements for individual types of plated articles However: White bronze seems the suitable for some purposes and is already used for plating of jewellery, buttons, eye wear, watches, etc. But involves use of cyanide containing baths Cost is 2.5 times the price of nickel plating Does not fulfil corrosion requirement (e.g. cars) and wear resistance needed for sanitary fittings

17 Conclusions Zinc plating on steel with trivalent chromium, a cobalt-free passivation layer plus additional topcoat Good corrosion resistance But corrodes over time and does not preserve its brightness It seems very difficult to replace nickel plating as subcoat for chromium (VI) plating e.g. on furniture. Copper as subcoat does not apply to steel pipes and tubes. No alternative has been identified for industrial scale plating of such items.

18 Recommendations Include independent expertise in the consultant team Good experience from working group consisting of experts from representative industry stakeholders from different European countries Information gathering from individual experts within industry is more efficient that questionnaires sent to industry broadly Validation of the final report by a broader group including the end users End users have a key role: very often those who request specific properties

19 Thank you Jens Tørsløv