Friction reduction and wear behavior of ZnO/SnS-reinforced Fe3Al composites synthesized via spark plasma sintering

Abstract

In this study, Fe 3 Al-based self-lubricating composites reinforced with ZnO and SnS were synthesized via Spark Plasma Sintering (SPS) and investigated for their tribological performance under dry sliding conditions. The composites were tested against Si 3 N 4 ceramic counterparts at a constant sliding speed of 0.18 m/s under varying normal loads (4–13 N). The incorporation of 10 wt% ZnO and 10 wt% SnS led to a reduction in both hardness (from 280 ± 13.33 HV1 to 237 ± 9.78 HV1) and density (to 6.11 ± 0.022 g/cm 3 ). Despite this, the modified composite Fe 3 Al/ZnO + SnS (FAZS) exhibited significantly lower and more stable coefficients of friction across most loading conditions, attributed to the formation of lubricating tribo-films by the additives. However, FAZS showed higher wear rates than pure Fe 3 Al (FA), particularly under elevated loads, likely due to diminished matrix hardness. Microstructural and surface analyses confirmed the presence of multilayered tribological structures in FAZS, including oxide-rich LYs and mechanically mixed zones that enhance frictional stability. These findings indicate that while ZnO and SnS reinforcement compromises wear resistance under high stress, it improves friction behavior, making the FAZS composite suitable for moderate-load applications where reduced friction and adaptive wear response are prioritized.