Microstructure and tribological characterizations of Ni-based self-lubricating coating

In this study, HFIS304 coating comprising NiCr (80/20) matrix (60 wt%) combined with Cr2O3 (20 wt%), Ag (10 wt%) and eutectic BaF2/CaF2 (10 wt%) as solid self-lubricants additives has been successfully prepared by cold isostatic pressing and high-frequency induction sintering (HFIS) on a Ni-based superalloy rod. The microstructure of HFIS304 was fine and dense, the size of Cr2O3, BaF2/CaF2 particles was below 1 μm, and that of Ag particles about 1 μm. The tribological properties of HFIS304 composites against Inconel X-750 were examined. The wear resistance and friction coefficient of the HFIS304 were superior to that of the PS304 in the temperature range from room temperature to 600 °C. The improvement in wear resistance of the HFIS304 was discussed in the terms of its microstructural characteristics. Additionally, the model of high temperature self-lubricating particles was proposed.