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2999 |
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Tuesday, September 27, 2011, Saal C2.2 2:00 PM Characterization & Testing 1 |
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Understanding of spray coating adhesion through the formation of a single lamella |
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Simon Goutier* / University of Limoges, France Michel Vardelle / SPCTS, University of Limoges, France Pierre Fauchais/ SPCTS, University of Limoges, France |
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Plasma spraying allows melting micrometer particles, which flatten in about one microsecond onto the substrate to build a coating by layering solidified splats. The coating adhesion is essential and depends mainly on the behaviour of first splats in contact with substrate. However in standard spray conditions about 108 particles/s impact onto the substrate, making difficult the understanding of the role of particle parameters onto the sprayed coating quality. In order to have a better insight, it is necessary to study the formation of a single splat. The experimental set-up developed comprises a fast (50 ns) two colour pyrometer and an imaging system, i.e., two fast CCD cameras triggered by the velocity signal. On the one hand, this work is focused on the particle flattening onto different types of substrates. The studied parameters are the particle impact velocity, temperature, and diameter of the particle prior to its impact and on the other the substrate characteristics (temperature, oxide layer composition, thickness, roughness, adsorbates and condensates lying at its surface&) On the second hand, coatings have been made in the splats spray conditions for measuring their corresponding adhesion and hardness. |