Multilayer structure design for preparing ultralow wear amorphous carbon films

This study promotes a thick amorphous carbon film with ultralow wear by multilayer design of a-C:H:Si_n+1/GLC_n under different modulation periods using magnetron sputtering. The results illustrates that the sufficiently thick a-C:H:Si top layer serve as excellent lubrication layer and the GLC provides support, while the multilayer structure alleviates the internal stress, which hindered the generation and extension of longitudinal cracks, avoiding the wear penetration and layer depletion. The friction coefficient of a-C:H:Si₂/GLC film with a top layer thickness of 750 nm was 0.06 and the wear rate was even lowered to 4.96 × 10⁻⁹ mm³/Nm for 10 h friction. The friction and lubrication mechanism is discussed in terms of the microstructure, mechanical properties and friction behaviors.