A Microstructural and Wear Resistance Study of Stainless Steel-Ag Coatings Produced through Magnetron Sputtering

Abstract

This paper presents a study of the tribological properties of stainless steel coatings with varying Ag contents, deposited via magnetron sputtering. The growth of the coatings was done in Ar and Ar + N2 atmospheres in order to change the crystalline phase in the coating. The analysis of the chemical composition was performed using energy-dispersive X-ray spectroscopy (EDS) and the structural analysis was performed via X-ray diffraction (XRD). The adhesive wear resistance and the friction coefficient were evaluated using the ball-on-disk test with a ball of alumina. The coatings’ adhesion was measured with a scratch tester and the mechanical properties were evaluated with a nanoindenter. The morphology of the films and the wear track were characterized via scanning electron microscopy (SEM). By means of XRD, phases corresponding to the body-centred cubic (BCC) structure were found for the coatings deposited in an inert atmosphere and face-centred cubic (FCC) for those deposited in a reactive atmosphere. A more compact morphology was observed in coatings with a higher silver content. The values of the hardness increased with an increase in the silver content and the presence of nitrogen in the coatings. In the wear traces, mainly mechanisms of oxidative and adhesive wear and plastic deformation were found. The coefficient of friction decreased with an increase of silver in the coatings, whereas the wear rate decreased.