Effects of graphite contents on the microstructure evolution, mechanical properties and high temperature tribological behavior of Cu–Ni–Al/Gr solid-lubricating composites

High temperature copper matrix self-lubricating composites are essential for industrial applications. This paper fabricated the Cu–Ni–Al/Gr solid-lubricating composites with 2.5–10 wt% graphite. Effects of graphite contents on the tribological behavior at room temperature to 500 ℃ were thoroughly studied. The conclusions present that the addition of graphite significantly improves tribological properties while no further enhancement can be made when graphite reaches 7.5–10 wt%, which shows the friction coefficient of 0.04–0.22 and wear rate of (1.02–10.12)× 10−5 mm3/Nm. The excellent tribological performance at 25–500 ℃ is attributed to the synergistic effects of the self-lubricating property provided by graphite lubricant and the tribo-oxide layer formed during the sliding process.