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.

Programme(s)

• FP4-ENV 2C - Specific programme of research and technological development in the field of environment and climate, 1994-1998

Topic(s)

• 0202 - Technologies and methods for assessing risks to and protecting and rehabilitating the environment

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