Tribological investigation of zirconium nitride/silver nanocomposite structures

Nanocomposite films of zirconium nitride/silver were deposited by unbalanced magnetron sputtering on stainless steel SS316 substrates. The structure of the films was characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The films were found to form a dense and homogeneous microstructure whereby nanocrystals of Me are distributed evenly throughout the ZrN matrix. The elemental composition was determined by X-ray photoelectron spectroscopy (XPS). The mechanical properties of these films were analyzed using an atomic force microscope (AFM) in conjunction with Hysitron Triboscope. The hardness and elastic modulus were found to depend on elemental composition and deposition parameters. Microwear measurements were carried out using positive constant normal loads and the wear tracks were imaged and processed using the ProScan Image Processing software. Reported are values for the friction coefficients, residual depth of indentations, wear volumes, and surface roughness. Finally, the coatings were worn against ball-bearing steel using a ball-on-disk tribotester. A low wear coefficient of 2.1 × 10− 7 mm3/s was obtained for a load of 5 N.