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2716 |
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Tuesday, September 27, 2011, Saal B2.1 2:25 PM Cold Spraying 1 |
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Influence of powder particle oxidation on poperties of cold sprayed tantalum |
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Laure-Line Descurninges* / MINES ParisTech / Materials Research Center / C2P-Competence Center for spray Processing, CNRS UMR 7633, France Michel Jeandin/ MINES ParisTech / C2P-Competence Center for spray Processing, France Anass Nifa/ ENSAM / PIMM, France Laurent Berthe/ ENSAM / PIMM, France Michel Boustie/ Institut P/ENSMA, France Kazuhiro Ogawa/ FRI / Tohoku University, Japan Thierry Laguionie/ CEA, France Luc Bianchi/ CEA, France |
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The adhesion mechanisms involved in the cold spray coatings are not still well elucidated. The quality of the deposit does depend mainly on particles and dynamic characteristics (which result from nozzle type, nozzle-substrate distance, etc.). The present work is based on the study of particle-substrate and particle-particle interfaces in the tantalum-copper coating-substrate system. The content focuses on the influence of the oxygen content in the starting powder on interface features, consequently on coating properties. Tantalum powders with different oxygen levels were studied using SEM (Scanning Electron Microscopy) and nano-indentation testing. Their oxide layers were also characterized (type of oxide, thickness of the layers) by combining EPMA (Electron Probe Microanalysis) and XRD (X-Ray Diffraction). Laser shock spallation of cold-sprayed Ta coatings onto Cu targets was developed as a reliable and flexible process to result in Ta-Cu interfaces. The study of this interface was carried out to go into interface phenomena involved in cold spray and related properties. The role of powder oxidation on interface soundness was exhibited. Adhesion was shown to be all the lower as powder oxygen content was higher, using LASAT® ( Laser Shock Adhesion Test ) in addition to direct observation of interfaces. Results were exploited to discuss properties of the corresponding Ta coatings onto Cu, i.e. which were cold sprayed using powders with different oxygen contents. |