Research project NM/A/06 (Research action NM)
CONTEXT
The successful development and production of protective coatings on steel need an accurate, fast and sensitive technique for the determination of the thickness and the chemical composition of these coatings. One of the few potentially suitable techniques is glow discharge optical emission spectrometry (GD-OES). Setting up an appropriate GD-OES method implies an extensive study of sputter behaviour, analytical parameters and reference materials.
THE PROJECT
The main objective of the project is the development of a method for the determination of thickness and chemical composition of zinc-based metallic coatings on steel, using RF GD-OES, i.e. GD-OES with a radio-frequency source. The follow-up of the project is done by representatives of two important Belgian steel producers and by an international authority in the field of GD-OES. The project focuses on two types of zinc-based coatings of high industrial importance.
The main tasks in the project are:
- selecting reference materials;
- determining sputter rates of reference materials;
- optimising analytical parameters;
- calibration;
- applying and optimising the method;
- detailed description of the method;
- evaluating (round robin) and finalising the method.
By combining efforts, Vito and Certech create a powerful network:
- two state-of-the-art RF GD-OES instruments;
- all complementary characterisation techniques required for the project;
- experience with the application of RF GD-OES to industrial problems;
- experience with a wide range of techniques for the characterisation of coatings;
- activities in different standardisation projects for the characterisation of coatings.
The project aims to:
- provide a detailed description of a method for the determination of the thickness and the chemical composition of Zn-based metallic coatings on steel, using RF GD-OES;
- study the discharge phenomenon as a function of the surface composition and the coating thickness;
- single out the critical operating parameters;
- optimise the operating parameters;
- apply the optimum operating conditions to the analysis of industrial metallic coatings;
- assess the quality and practical use of the method by organising interlaboratory comparisons;
- contribute to a fast and reliable method for quality control of metallic coatings and surface treatments.
EXPECTED PRODUCTS AND RESULTS
In addition to an RF GD-OES method for the determination of the thickness and the chemical composition of zinc-based coatings on steel, as a valuable (faster and environment friendlier) alternative for ICP-MS, the project offers a deeper understanding of the critical parameters in these measurements. In particular and opposed to what is generally accepted, it was found that the so-called relative sputter rates (RSR) vary with the source type (DC versus RF) - is of limited use and might even become a major source of errors.
The success of the project might stimulate a new standardisation initiative for the development of a GD-OES method for the analysis of very thin (inorganic and organic) surface treatments on substrates of high industrial relevance, such as steel and aluminium.
SCIENTIFIC COLLABORATIONS
Frequent exchange of GD-OES experiences and comparison of results with OCAS (Belgium), EMPA (Switzerland), SIMR (Sweden) and Alcan (UK).
USERS COMMITTEE
The users committee consists of production and characterisation specialists of the steel industry and of an internationally renowned scientist in the field of GD-OES:
- H. Dillen and C. Xhoffer (OCAS)
- M. Dubois (Cockerill-Sambre)
- R. Payling (University of New South Wales, Australia)
PROMOTERS
Stefan KUYPERS
Vlaamse Instelling voor Technologisch Onderzoek
Boeretang 200
B-2400 MOL
Tel: +32 14 33.57.51
Fax: +32 14 32.11.86
E-mail: stefan.kuypers@vito.be
Yann BOURGEOIS
Centre de ressources technologiques en chimie
Zone Industrielle C
B-7180 SENEFFE
Tel: +32 64 52.02.11
Fax: +32 64 52.02.10
E-mail: yann.bourgeois@certech.be
Glow discharge optical emission spectrometry for the analysis of metallic coatings on steel, "GAMeS" : final report
Brussels : Federal Science Policy, 2005 (SP1469)
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