Tribological behaviors of in-situ textured DLC films under dry and lubricated conditions.

• Textured DLC films were in-situ deposited by masking substrate with metallic meshes. • Covered region became concave part while exposed region became protruding part. • In-situ surface texturing improved film hardness, elastic modulus and lipophilicity. • DLC-T52% reached the lowest COF and wear rate under dry and lubricated conditions. Surface texturing is emerging as one of the viable means that can be applied to improve the tribological properties of diamond like carbon (DLC) films. In this study, textured DLC films were in-situ fabricated by masking the substrate with metallic meshes during the deposition process. The tribological behaviors of the textured DLC films with micro-dimples densities of 39%, 52% and 58% were studied and compared with that of the un-textured DLC films under dry friction and liquid lubrication conditions. The results showed that the textured DLC films with micro-dimples density of 52% exhibited the lowest average coefficient of friction (COF) and wear rate both under dry friction and liquid lubrication conditions. The improved tribological performance of the textured DLC films with optimum micro-dimples density (52%) under dry friction could be attributed to the friction-induced graphitization of the textured layer and entrapment of wear debris in the micro-dimples. Under liquid lubrication condition, the micro-dimples played the double role of wear debris and lubricating oil reservoirs, then the graphitized textured layer on the worn surface combined with the liquid lubrication film formed a solid-liquid duplex lubricating, thus achieving significantly lower friction and wear. [ABSTRACT FROM AUTHOR]