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| Abstract No.: |
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Scheduled at:
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Thursday, June 08, 2017, Hall 28 11:00 AM
Tribological Coatings
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| Title: |
A study on the tribological behavior of arc sprayed vanadium doped stellite coatings
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| Authors: |
Leif Gereon Hagen* / University of Dortmund, Germany
Wolfgang Tillmann / TU Dortmund University, Institute of Materials Engineering, Germany
Daniel Duda/ TU Dortmund University, Institute of Materials Engineering, Germany
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| Abstract: |
Due to good performance in abrasive and sliding wear and enhanced oxidation behaviour, coatings based on Co-Cr-W alloys are widely used in industrial applications, where the material is exposed to high temperature. Within the scope of this study, a Co-based alloy similar to commercial Stellite 6®, which additionally contains V (20 wt.%), was deposited by Twin Wire Arc Spraying (TWAS) process. Multi-criteria optimization using statistical design of experiments (DoE) have been carried out in order to produce adequate coatings. The produced coatings have been analyzed with respect to their tribological behaviour at elevated temperatures. Dry sliding experiments were performed in the temperature range between 25 °C and 750 °C. Oxide phases were identified in-situ in the investigated temperature range by x-ray diffraction (XRD) using synchrotron radiation. The V-doped Stellite coating possesses a reduced coefficient of friction (COF) of about 0.37 at elevated temperatures (above 650°C), which was significant lower when compared to conventional Stellite 6® coating that serves as reference. In contrast, both produced coatings feature a similar COF under room temperature. X-ray diffraction reveals the formation of Magnéli phases above 650 °C. The formation of vanadium oxides in sliding contact under elevated temperature exhibits the ability of self-lubricating behaviour, thus leading to enhanced tribological properties.
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