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

摘要

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 degrees C and +100 degrees'C, and pressures ranged from ambient to as low as 1 x 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 degrees C and in vacuum at -100 degrees C. In vacuum at 25 degrees C and 100 degrees C, the mean friction coefficients (mu(mean)) 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 degrees C, in vacuum at 25 degrees C and 100 degrees C. But the friction became unstable in vacuum at -100 degrees C. Examinations, analyses and profiles of the friction surfaces and subsurfaces corroborated the correlation between environments and tribological behavior and wear mechanism. (C) 2014 Elsevier B.V. All rights reserved.