A gold coated carbon nanotubes composite was used as a contact material in Micro-Electrical-Mechanical-System (MEMS) switches. The switching contact was tested under typical conditions of MEMS relay applications: load voltage of 4 V, contact force of 1 mN, and load current varied between 20-200 mA. This paper focuses on the wear process over switching lifetime, and the dependence of the wear area on the current is discussed. It was shown that the contact was going to fail when the wear area approached the whole contact area, at which point the contact resistance increased sharply to three times the nominal resistance.

Multi-Walled CNT (MWCNT) are synthesized on a silicon wafer and sputter coated with a gold film. The planar surfaces are mounted on the tip of a piezo-electric actuator and mated with a gold coated hemispherical surface to form an electrical contact. These switching contacts are tested under conditions typical of MEMS relay applications; 4V, with a static contact force of 1mN, at a low current between 20-50mA. The failure of the switch is identified by the evolution of contact resistance which is monitored throughout the switching cycles. The results show that the contact resistance can be stable for up to 120 million switching cycles, which are 106 orders of higher than state-of-the-art pure gold contact. Bouncing behavior was also observed in each switching cycle. The failing mechanism was also studied in relation to the contact surface changes. It was observed that the contact surfaces undergo a transfer process over the switching life time, ultimately leading to switching failure the number of bounces is also related to the fine transfer failure mechanism.