Reduced friction on γ-Mo2N coatings deposited by high power impulse magnetron sputtering on microstructured surfaces

Wear-resistant molybdenum nitride (γ-Mo2N) layers are deposited on topographically modified surfaces. Mechanical embossing using diamond decorated stamps is employed to produce steel surfaces containing pit structures with typical lateral dimensions of about 10 µm. Subsequent vacuum deposition of Mo2N by high power impulse magnetron sputtering (HiPIMS) allows the coating of the surfaces while preserving the surface topography. The so produced surfaces exhibit a substantial reduction of the typically high coefficient of friction (COF). This is revealed in tribological tests in comparison to coatings on non-modified surfaces. Spatially resolved investigations of the obtained abrasion pattern after tribology measurements under high loads and increased temperature allows the description of the decisive tribological processes.