Tribological behaviour of nano-zirconia reinforced iron-based self-lubricating composites for bearing applications

In this research work nano zirconia (ZrO2) as ceramic reinforcement was added to strengthen Fe-Cu-Sn based composites and MoS2 was added to control their tribological properties. The composites were fabricated by powder metallurgy technique. XRD and SEM analysis revealed the presence of phases (Cu2FeSn, Sn11Cu41, Fe5Sn3, ZrFe2, and FeMo2S4) that influenced the properties of the composites. The microhardness value of 2.12 GPa and nano hardness of similar to 22 GPa was acquired in case of nano-ZrO2 reinforced composites and detailed analysis of worn surfaces was carried out through SEM, EDS, AFM and optical microscopy. Tribological properties examined using the ball-on-disk tribometer revealed lower friction (0.128) and wear rates for the composite containing 0.5 wt% of MoS2 and 2 wt% of ZrO2 making them a potential bearing material.