Intrinsic self-lubricity of layered Ti3AlC2 under certain vacuum environment

In this study, we report that a layered Ti3AlC2 ceramic exhibited three distinct tribological behaviors at different vacuum degrees. It is firstly found that the layered Ti3AlC2 exhibited intrinsic self-lubricity under vacuum degree from 2.0×104 to 5 Pa with the coefficient of friction (CoF) as low as 0.2 and nearly no wear. Under lower 0.1 Pa and air atmosphere, however, it showed lubrication failure. Under lower 0.1 Pa, The CoF abruptly rose after transitory low friction in initial duration and deteriorated wear occurred in the Ti3AlC2. The CoF sluggishly ascended to stable value from 0.2 to 0.7 in air. The lubricating mechanism of Ti3AlC2 ceramic was proposed.