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5293 |
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Friday, June 09, 2017, Hall 12 11:00 AM Power Generation - Steam |
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The high temperature wear and oxidation behavior of CrC-based HVOF coatings |
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Sarka Houdkova* / VZU Plzen s.r.o., Czech Republic Zdenek Cesanek / University of West Bohemia, Czech Republic Frantisek Lukac/ Institute of Plasma Physics, Czech Republic Eva Smazalova/ University of West Bohemia, Czech Republic |
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The 3 commercially available CrC-based powders with different kind of matrix (Cr3C2-25%NiCr; Cr3C2-25%CoNiCrAlY and Cr3C2-50%NoCrMoNb) were deposited by HVOF JP-5000 spraying gun, evaluated and compared. The sliding wear resistance, measured at room and elevated (T=600°C) temperature according to ASTM G-133, and oxidation resistance in air (T=600°C) and hot steam environment (p=24 MPa; T=600°C) were evaluated with respect to their potential application in steam power industry. The surface oxidation and microstructure changes were evaluated by SEM and XRD. The NiCr matrix proved to provide high oxidation and sliding wear resistance of the coating regardless volume content. On the contrary, the Cr3C2-25%CoNiCrAlY coating was subjected to massive oxidation of carbide particles. The low cohesive strength and high porosity of Cr3C2-25%CoNiCrAlY was identified responsible for its poor oxidation resistance in hot steam environment. The sliding wear resistance was found comparable at room temperature, regardless the matrix composition and content, while at elevated temperatures, the higher volume content of matrix led to higher wear of coating material. |