Formation of discrete periodic nanolayered coatings through tailoring of nanointerfaces—Toward zero macroscale wear

Notwithstanding the success of nanolayered coatings in the reduction of wear at nano-/microscales, the improvement of the wear resistance at the macroscale remains an issue. Moreover, the effects of nanointerfaces in nanolayered coatings on their macrotribological properties are not understood well. This paper reports on the engineering of nanointerfaces in diamond-like C/Cr nanolayered coatings to tailor their characteristics including the degree of intermixing, defects, and Cr growth mode. The result was the fabrication of a coating with subnanometer-thick periodic albeit discrete Cr interlayers. This was achieved using our patented deposition technique. This coating contained less interfacial defects compared to classic nanolayered coatings with continuous nanolayers and presented record-breaking wear rates at the macroscale. Finite Element analysis was performed and micropatterning strategy was used to reduce the wear rate further. Last, we report on discovery of a dimensionless parameter that can be used to predict the wear resistance of carbon-based nanolayered coatings.