Evolution of Maximum Contact Stresses in Amorphous Carbon Coated Silicon During Sliding Wear Against Si3N4 Ball

The evolution of the maximum contact stresses in amorphous carbon coated silicon during sliding wear against a Si3N4 ball was investigated. Amorphous carbon coating was prepared on a silicon substrate by the electron cyclotron resonance (ECR) plasma sputtering method. Surface morphologies of the coating and counterpart were measured by an atomic force microscope (AFM). The friction and wear behavior of the coating was studied by a ball-on-disk tribometer. The cross-sections of the wear tracks at different wear stages were observed with a scanning electron microscope (SEM). Maximum contact stresses with different coating thicknesses were calculated by the three-dimensional semi-analytical method (SAM). The results demonstrated that when taking surface asperities into consideration, maximum shear stress at the bonding interface and adjacent substrate showed a dramatic increase during wear and should be responsible for the initiation and propagation of the cracks observed at the final stage of sliding.