Roughness influence on macro- and micro-tribology of multi-layered hard coatings on carbon fibre polymer composite

Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi-layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP). Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal sliding testing against alumina, the friction coefficients are lower for the smooth coatings, but their wear rate is higher due to low-cycle fatigue caused abrasion.