Tribological properties of TiN/Ag nanocomposite coatings

Morphology, structure, and tribological behavior of magnetron co-sputtered TiN/Ag nanocomposite coatings deposited at 150 C with an Ag content in the range of 7-45 at.% were characterized. The coatings show a columnar structure with embedded Ag crystallites of 3-50 nm in diameter, where the columns are characterized by a layered structure with Ag-poor and Ag-rich layers. These layers originate from sample rotation during deposition, where the layer thickness increases with increasing Ag content. These Ag layers become continuous over a critical Ag content. At room temperature the friction coefficient is determined by the film structure, whereas friction and wear at high temperature depend on segregation of Ag to the surface.