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Substitution of Toxic Chromium 6 in Conversion Coating Technologies

Objective



This project aims to develop technology for the surface treatment of a range of metals and alloys in order to eliminate the use of hexavalent chromium compounds. These chemicals are widely used throughout Europe and elsewhere to deposit conversion coatings on many metals and articles. However, their application has serious risks, since they are carcinogenic, and are a fire hazard. Disposal of spent solutions is also costly, since reduction to the trivalent state, which is non-toxic, is generally required In general terms, the technical programme will proceed along four main lines, i.e.
(a) Development of immersion baths based upon permanganate.
(b) Anodising in the presence of manganous ions.
(c) Deposition of chromium trioxide films from trivalent chromium baths.
(d) Extension to zinc coated steel and other active metals.
Processes based on routes (a) - (c) have been described in previous studies, with particular success being achieved on oxide covered metals such as aluminium, and will be subjected to more complete development and assessment. Similar techniques will be applied in (d) to obtain a suitable method for use on zinc coated steel. Various metals, in sheet form, and small commercially produced articles will be used as test pieces throughout.
After treatment the results will be assessed by several methods including rapid electrochemical tests of corrosion resistance, salt spray tests, and paint adhesion. The involvement of many SMEs will ensure that the choice of work pieces, and their subsequent appraisal after coating, are relevant to the needs of industrial users.
In the later stages of the project, on line coating of articles in the work place environment will be demonstrated. Pilot trials of the more complex innovative routes will also be carried out. The participation of a large number of SMEs in the project will ensure that the final evaluation, and the subsequent exploitation are carried out in a realistic manner.

Funding Scheme

CRS - Cooperative research contracts

Coordinator

Acorn Hardas Limited
Address
Clover Street
NG17 7LJ Kirby-in-ashfield
United Kingdom

Participants (15)

AB FERRORPRODUKTER
Sweden
Address
Import Gatan 19-21
402 72 Goeteborg
ARCHITECTURAL POWEDER COATINGS LTD.
United Kingdom
Address
Cambridge Road Blaydon Industrial Park
NE21 5AB Blaydon-on-tyne
ASHTON AND MOORE LTD.
United Kingdom
Address
3,Legge Lane 3
B1 3LF Birmingham
Coil Coatings Technologies B.V.
Netherlands
Address
27,Markweg Zuid
4794 SN Heijningen
EA TECHNOLOGY LTD.
United Kingdom
Address
Capenhurst
Chester
FUNDACION INASMET - ASOCIACION DE INVESTIGATION METALURGICA DEL PAIS VASCO
Spain
Address
12,Mikeletegi Pasealekua 2
20009 San Sebastian
Galvanotecnia y Devivados S.A.
Spain
Address
41,Amillaga
20570 Bergara
Inter Euro Technology Limited Tradingas the Faraday Centre
Ireland
Address
Dun Eoghain
41 Chapelstown
Mavom B.V.
Netherlands
Address
6,Handelsweg
2404 CD Alphen Aan Den Rijn
Ossian Ltd.
Ireland
Address
Ballyvourney
108 Macroon
Procoat Tecologias SL
Spain
Address
36-44,Camino De La Riera
08191 Rubi
Puretech Ltd.
United Kingdom
Address
Huddersfield Road
WF13 3JW Ravensthorpe
Surface Technology PLC
United Kingdom
Address
Long Causeway
LS9 0NY Leeds
TWICKENHAM PLATING GROUP PLC
United Kingdom
Address
Brent Way
TW8 8HU Brentford - Middlesex
The Institute of Metal Finishing
United Kingdom
Address
48,Holloway Head
B1 1NQ Birmingham