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| Abstract No.: |
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Scheduled at:
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Wednesday, September 28, 2011, Saal C2.2 9:25 AM
Characterization & Testing 3
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| Title: |
Microtomographic analysis of splat formation and layer build-up of a thermally sprayed coating
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| Authors: |
Jens Nellesen* / RIF e.V. - Institut für Forschung und Transfer, Germany
Wolfgang Tillmann / Institute of Materials Engineering, Germany
Mohamed Abdulgader/ Institute of Materials Engineering, Germany
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| Abstract: |
Thermal spraying is a materials processing technique, which is based on the combination of thermal and kinetic energy. The used feedstock is melted in a hot flame and the melt is atomized and/or accelerated by means of atomization or process gases. The formed particles are rapidly solidified and consolidate to form splats as they hit a pre-treated substrate. The splats pile one-on-top-of-other forming lamellas and creating the final coating.
In the work presented a combination of cored wire (WC as filling powder) and massive wire (copper) were simultaneously sprayed using twin wire arc spraying process. 3D micro tomography was used in order to gain knowledge about splat formation and layer build-up. Due to the high attenuation coefficient of tungsten in comparison with copper and carbon tungsten-rich particles and splats can easily be spotted in the tomogram of the coating layer. It turns out that besides irregular formed flat splats also ball-shaped particles exist in the coating layer which suggests that the spherical particles impacted on the substrate in an unmolten state. By 3D data processing the tungsten-rich particles were visualized to analyze their spatial distribution as well as their geometric parameters were quantified. This work aims at contributing to the understanding of spraying process.
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