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Hybrid Co-Cr/W-WC and Ni-W-Cr-B/W-WC coating systems

Luc Vernhes, Marwan Azzi, Étienne Bousser and Jolanta-Ewa Sapieha

Paper (2015)

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The mechanical, tribological, and corrosion properties of two hybrid coating systems were assessed: 1) a tungsten–tungsten carbide (W-WC) top layer and a laser cladded cobalt– chromium (Co-Cr) interlayer (Stellite 6 superalloy) applied to a 316 stainless steel substrate; and 2) the same W-WC top layer and an HVOF spray-and-fused Ni-W-Cr-B interlayer (Colmonoy 88 superalloy) applied to an Inconel 718 substrate. X-ray diffraction, energy dispersive spectroscopy, and scanning electron microscopy were used to analyze the microstructure of the coating layers. Microindentation was used to measure surface hardness and the hardness profile of the coating systems. Rockwell indentation was used to assess coating adhesion according to CEN/TS 1071-8. Surface load-carrying capacity was also assessed by measuring micro- and macrohardness at high loads. Tribological properties were assessed with a linear reciprocating ball-on-flat sliding wear test, and corrosion resistance was measured by potentiodynamic polarization and electrochemical impedance spectroscopy. W-WC layers showed class I adhesion to both the SS 316 and Inconel 718 substrates, with and without an interlayer. Hardness profile measurements on cross section showed hardness of 13.6 GPa and 7.0 GPa for W-WC and Co-Cr, respectively, with average hardness of 9.7 GPa for Ni-W-Cr-B. Furthermore, hardness measurements at different high loads revealed that the addition of an interlayer increases surface hardness by up to 200% compared to the same coating system provided without an interlayer, quantifying the additional loadcarrying capacity provided by the supplementary interlayer. The tribological measurements show that, except for the Inconel 718 / Ni-W-Cr-B / W-WC system, the hardest interlayer or substrate leads to the highest wear rates. In addition, the W-WC layer showed excellent corrosion protection, with no pitting observed after potentiodynamic polarization testing.

Uncontrolled Keywords

316 stainless steel; cobalt chromium-tungsten-tungsten carbide; energy dispersive spectroscopy; high-velocity oxyfuel spraying; microindentation hardness; nickel-tungsten-chromium-boron-tungsten-tungsten carbide; scanning electron microscopy; X-ray diffraction

Department: Department of Engineering Physics
PolyPublie URL: https://publications.polymtl.ca/35599/
Conference Title: International Thermal Spray Conference and Exposition (ITSC 2015)
Conference Location: Long Beach, CA, United states
Conference Date(s): 2015-05-11 - 2015-05-14
Publisher: ASM International
DOI: 10.31399/asm.cp.itsc2015p1031
Official URL: https://doi.org/10.31399/asm.cp.itsc2015p1031
Date Deposited: 18 Apr 2023 15:07
Last Modified: 05 Apr 2024 11:28
Cite in APA 7: Vernhes, L., Azzi, M., Bousser, É., & Sapieha, J.-E. (2015, May). Hybrid Co-Cr/W-WC and Ni-W-Cr-B/W-WC coating systems [Paper]. International Thermal Spray Conference and Exposition (ITSC 2015), Long Beach, CA, United states. https://doi.org/10.31399/asm.cp.itsc2015p1031



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