La production des plasmas thermiques

Université de Limoges, faculté des sciences, CNRS URA 320, LMCTS, équipe Plasma, laser, matériaux, 123, avenue Albert Thomas, 87060 Limoges cedex, France
International Journal of Thermal Sciences - INT J THERM SCI 01/1996; 35(416):543-560. DOI: 10.1016/S0035-3159(99)80081-6

ABSTRACT Cet article fait suite à une journée d'études organisée par la section Convection de la Société Française des Thermiciens (SFT) sur le thème Transferts convectifs par les jets (Paris, 15 mars 1995).

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    ABSTRACT: Thermal spray processing is used to confer specific in-service properties to components via the production of a coating between 50 μm (minimum value) to a few millimeters thick. Thermal spray represents a global market of about 4.8 Billion Euros (i.e., ∼ US$5 billion) in 2004; 30% of which is European based. 50% of this activity is devoted to plasma spray processing with about 90% dedicated to direct current (DC) plasma torches. Several developments of new torch architectures, among which three-cathode torches, have evolved recently. However, most of the recent progress has been applied to conventional DC torches. The advances were related to two prime factors: (i) the development of industrial sensors permitting to diagnose the processes during spray operation (especially in-flight particle characteristics in terms of their surface temperature and velocity) and additionally the monitoring of the substrate and coating temperatures with the objective of controlling the operating parameters via a close-loop controller; (ii) the adaptation of plasma spray systems to manufacture nano-structured coatings via the development of suspension plasma spray and solution plasma spray. As well, there has been an enhanced understanding of the mechanisms controlling the coating formation and of the effects of the arc root fluctuations; thereby permitting a more robust process. This paper develops the above points by presenting focused examples.
    Surface and Coatings Technology 10/2006; · 2.20 Impact Factor
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    ABSTRACT: In this study a new numerical approach of the fluid dynamic, the lattice Boltzmann method (LBM), is used to solved the stream in a atmospheric Argon-nitrogen plasma jet. The axial symmetry and the variation of density, viscosity and conductivity with the temperature are taken into account. The reliability of the results are evaluated from the shareware GENMIX and Jets & Poudres. Comment: 6 pages
    CIFEM 2010; 02/2010
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    ABSTRACT: Thermal spraying is a versatile technique to manufacture coatings which offers a large choice of processes (i.e., plasma spraying, flame spraying, electric arc spraying, etc.) and materials (i.e., metallic, ceramic, polymer and composite materials). To obtain functional coatings exhibiting selected in-service properties, combinations of processing parameters have to be planned. These combinations differ by their cost and by their influence on the coating properties and characteristics. In order to control the manufacturing process, one of the challenges nowadays is to recognize parameter interdependencies, correlations and individual effects on coating properties and characteristics and influences on the in-service properties. This is why a robust methodology is needed to study theses interrelated effects. A statistical method, responding to the previous constrains, was implemented to correlate the atmospheric plasma spray processing parameters to the coating properties. This methodology is based on artificial neural networks which is a technique based on database training to predict property-parameter evolutions. This introductory work points out the implementation protocol, the database construction, the optimization process and an example of predicted results related to the deposition yield (i.e., deposited thickness per pass).
    Computational Materials Science 03/2004; · 1.88 Impact Factor