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1275 |
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Wednesday, June 04, 2008, Room 08 11:40 AM Diagnostics and Sensors 1 Modern process diagnostics offer a lot of possibilities for gaining data for both quality control and process knowledge. The recorded data is the base for process models and enhances the process knowledge |
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Study on the detection of melting temperatures and sources of errors using two-color pyrometry for in-flight measurements of plasma sprayed particles |
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Georg Mauer* / Forschungszentrum Jülich GmbH, Germany Robert Vaßen / Forschungszentrum Jülich GmbH, IEF-1, Germany Detlev Stöver/ Forschungszentrum Jülich GmbH, IEF-1, Germany |
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The microstructures of plasma sprayed coatings are considerably dependent on the characteristics of the powder feedstock particles. Particularly the melting status of the particles is critical. Thus, the accurate determination of the particle temperature is of importance. In-flight particle temperature measurements during atmospheric plasma spraying (APS) of Tungsten, Molybdenum, and Yttria stabilized Zirconia by two-color pyrometry are analyzed statistically. The particle temperature distributions allow assessing the melting status of the particles. Particularly the melting temperature and the particle fractions being still molten or already solidifying can be identified. Furthermore, the relevant systematic and material dependant sources for measurement errors using two-color pyrometry are investigated. Their influence is estimated and corrected best possible. As far as there is reliable data available on the emissivity of the powder material there is good agreement between the corrected measured melting temperatures and reference data. |