https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 05 Jun 2026 22:07:07 GMT 2026-06-05T22:07:07Z http://hdl.handle.net/10985/8661 Cr2C3–NiCr VPS thermal spray coatings as candidate for chromium replacement STAIA, M.H.; SUAREZ, M.; CHICOT, Didier; LESAGE, J.; IOST, Alain The present investigation has been carried out with the aim of determining the tribological behavior of a VPS chromium carbide coating both in the as-deposited and heat-treated conditions. A commercial powder of Cr2C3–25% NiCr was sprayed employing a VPS system (Medicoat AG, Switzerland) onto plain low carbon steel coupons. The samples were subsequently annealed for 2 h at 600 °C, 800 °C and 900 °C in Ar. The microstructural characterization was carried out by using SEM and XRD before and after the heat treatment of the samples. SEM observations were employed for determining the degradation mechanisms that took place during the wear tests. When the coated systems rubbed against alumina under a 5 N normal load in air, a progressive change in the mechanism, from a mixed adhesive and abrasive, to a predominant abrasive was observed, as the heat treatment temperature increased. The wear constants were found to be of the order of approximately 10− 6 mm3/N.m, which indicates a wear resistance of nearly 4 times higher in comparison with the wear results reported in the literature for similar coating systems obtained by employing HVOF deposition. However, the heat treatment carried out at 900 °C brought about only 20% increase in the sliding wear resistance of the coated system. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/8661 2013-01-01T00:00:00Z STAIA, M.H. SUAREZ, M. CHICOT, Didier LESAGE, J. IOST, Alain The present investigation has been carried out with the aim of determining the tribological behavior of a VPS chromium carbide coating both in the as-deposited and heat-treated conditions. A commercial powder of Cr2C3–25% NiCr was sprayed employing a VPS system (Medicoat AG, Switzerland) onto plain low carbon steel coupons. The samples were subsequently annealed for 2 h at 600 °C, 800 °C and 900 °C in Ar. The microstructural characterization was carried out by using SEM and XRD before and after the heat treatment of the samples. SEM observations were employed for determining the degradation mechanisms that took place during the wear tests. When the coated systems rubbed against alumina under a 5 N normal load in air, a progressive change in the mechanism, from a mixed adhesive and abrasive, to a predominant abrasive was observed, as the heat treatment temperature increased. The wear constants were found to be of the order of approximately 10− 6 mm3/N.m, which indicates a wear resistance of nearly 4 times higher in comparison with the wear results reported in the literature for similar coating systems obtained by employing HVOF deposition. However, the heat treatment carried out at 900 °C brought about only 20% increase in the sliding wear resistance of the coated system. http://hdl.handle.net/10985/9666 Fatigue behavior of a structural steel coated with a WC–10Co–4Cr/Colmonoy 88 deposit by HVOF thermal spraying LA BARBERA-SOSA, J.G.; SANTANA, Y.Y.; VILLALOBOS-GUTIERREZ, C.; CHICOT, Didier; LESAGE, J.; DECOOPMAN, Xavier; IOST, Alain; STAIA, M.H.; PUCHI-CABRERA, Eli-Saul The fatigue behavior of a SAE 4340 steel, coated with a 50% WC–10Co–4Cr/50% Colmonoy 88 deposit, by high velocity oxygen fuel (HVOF) thermal spray, has been investigated. The change in the maximum alternating stress with the number of cycles to fracture has been described by means of the relationship advanced by Stromeyer. A fractographic analysis has been carried out on some representative fracture surfaces, by means of scanning electron microscopy (SEM) techniques. The mechanical properties of the coating were characterized by means of nanoindentation tests. The results indicate that the coating is highly heterogeneous. Its deposition gives rise to a decrease in the fatigue strength of the substrate of ∼ 30%, in comparison with the uncoated substrate. The decrease in fatigue strength is due to the presence of stress concentrators at the substrate–coating interface, as well as the intrinsic characteristics of the coating. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/9666 2013-01-01T00:00:00Z LA BARBERA-SOSA, J.G. SANTANA, Y.Y. VILLALOBOS-GUTIERREZ, C. CHICOT, Didier LESAGE, J. DECOOPMAN, Xavier IOST, Alain STAIA, M.H. PUCHI-CABRERA, Eli-Saul The fatigue behavior of a SAE 4340 steel, coated with a 50% WC–10Co–4Cr/50% Colmonoy 88 deposit, by high velocity oxygen fuel (HVOF) thermal spray, has been investigated. The change in the maximum alternating stress with the number of cycles to fracture has been described by means of the relationship advanced by Stromeyer. A fractographic analysis has been carried out on some representative fracture surfaces, by means of scanning electron microscopy (SEM) techniques. The mechanical properties of the coating were characterized by means of nanoindentation tests. The results indicate that the coating is highly heterogeneous. Its deposition gives rise to a decrease in the fatigue strength of the substrate of ∼ 30%, in comparison with the uncoated substrate. The decrease in fatigue strength is due to the presence of stress concentrators at the substrate–coating interface, as well as the intrinsic characteristics of the coating.