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1546 |
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Wednesday, June 04, 2008, Auditorium 2 1:40 PM Cold Spraying 3 Everything around this young thermal spraying technique, possible applications and latest developments for equipment of high pressure and low pressure cold spraying, models and simulations for a deeper process knowledge |
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Cavitation resistance of cold sprayed and thermally sprayed copper coatings |
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Frank Gärtner* / Helmut Schmidt University of the Federal Armed Forces, Germany Tobias Schmidt / Helmut Schmidt University, Institute of Materials Engineering, Germany Thomas Klassen/ Helmut Schmidt University, Institute of Materials Engineering, Germany Heinrich Kreye/ Helmut Schmidt University, Institute of Materials Engineering, Germany |
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Under recently developed process conditions, cold spraying can supply coating qualities that show comparable mechanical strength to highly deformed bulk material. In contrast, properties of thermally sprayed coatings can be restricted by entrapped oxides. In cavitation testing, the materials response on cyclic loading conditions is very sensitive to internal defects, resulting in higher mass losses. Moreover, microstructural investigations of cavitated surfaces can be used to identify mechanisms of failure. For the example of copper as coating material, the present contribution compares the cavitation resistance of cold sprayed and thermally sprayed coatings. A deeper view into the type of defects obtained, their stability and their influence on coating performance is supplied by subsequent annealing procedures and respective failure analyses. Furthermore, the investigation of failure modes after different heat treatments yields valuable information concerning bonding and possi-ble process improvements. The obtained results are compared with mechanical properties of de-formed and similarly heat treated bulk materials. Such procedure could supply an estimate of the on fatigue resistance of respective coatings. |