Friction and wear behavior of copper matrix composite for spacecraft rendezvous and docking under different conditions

• The friction and wear behavior of a P/M friction material were investigated.
• Tribological tests were performed at various ambient temperatures and pressures.
• The friction surfaces and subsurfaces were characterized by SEM and EDS.
• The wear mechanisms under different operation conditions were revealed.

The tribological properties of a copper matrix composite (Cu-MMC) for use in spacecraft rendezvous and docking operations were investigated using a special ground system that was capable of testing at various temperatures and pressures. The temperature range was between −100 °C and +100 °C, and pressures ranged from ambient to as low as 1×10−4 Pa. The results indicate that the friction and wear behavior were identified as a function of the operation conditions. During braking operations, Cu-MMC showed the steady-state friction characteristics in air at 25 °C and in vacuum at −100 °C. In vacuum at 25 °C and 100 °C, the mean friction coefficients (μmean) exhibited significant fluctuations and the wear rates increased remarkably. While in the process of clutching operations, the tribological performances showed little sensitivity to friction cycles in air at 25 °C, in vacuum at 25 °C and 100 °C. But the friction became unstable in vacuum at −100 °C. Examinations, analyses and profiles of the friction surfaces and subsurfaces corroborated the correlation between environments and tribological behavior and wear mechanism.