Microstructure and wear properties of cold-sprayed NiCr-Tribaloy (T800) coating on Nimonic 80A

Tribaloys, renowned for their effectiveness in high-temperature anti-wear applications, derive their exceptional wear resistance from hard intermetallic Laves phases, such as Co3Mo2Si and CoMoSi, within a eutectic Co-solid solution. In this study, Tribaloy 800 (T800) particles were blended with NiCr particles, and the combined feedstocks were deposited using the cold spray (CS) technique over Nimonic 80A substrate. The aim was to enhance wear resistance at high temperatures (700 °C). Microstructural analyses were conducted on both the feedstock particles and the deposited material to discern the evolving phases, microstructures, morphologies, and to investigate localized bonding at the interface. Subsequently, dry sliding wear tests were performed on both the substrate and the deposited material at both ambient and elevated temperatures (700 °C) using an alumina ball as counter material. The specific wear rate obtained for the NiCr-T800 coating specimen and the substrate at room temperature was found to be 63 × 10−5 mm3/Nm and 12 × 10−5 mm3/Nm, whereas at 700 °C, it was found to be 10 × 10−5 mm3/Nm and 5 × 10−5 mm3/Nm, respectively. The coating comprising NiCr-T800 demonstrated significantly enhanced wear resistance at both temperatures. This improvement was attributed to several factors: the deformation of NiCr splats, the development of compressive residual strains due to high velocity impact of particles, the uniform dispersion of T800 particles, the evolution of hard Co3Mo2Si Laves phases, and the development of NiO, Cr2O3 and NiCr2O4 Glaze oxide layer at 700 °C. This Glaze layer acted as a barrier, impeding direct contact between the CS coating and the alumina ball. •Dense and adherent deposit of NiCr-T800 coating (2.1 mm thickness) was obtained.•The evolution of Co3Mo2Si Laves phase was obtained from the T800 particles.•The CoF of the deposit was multiple times lower than the substrate at RT and 700 °C.•The wear mechanism observed at RT are adhesive, delamination and oxidative wear which changed to oxidative wear at 700 °C.