Mechanical behavior of YSZ coatings co-deposited with Al and Ag on AISI 316L via RF sputtering

Abstract

This article presents nanohardness, coefficient of friction (COF), and wear of Yttria-stabilized zirconia coatings (YSZ) deposited on 316L steel substrates and co-deposited with Al and Ag. YSZ coatings were deposited via RF sputtering reactive phase technique. It is widely known that the RF sputtering technique produces stoichiometric coatings with high homogeneity and density. The average thickness of the coatings was 200 nm, and the X-ray diffraction study (XRD) showed the formation of alumina alpha (α-Al2O3) and metallic silver in the YSZ coatings deposited with Al and Ag, respectively. The mechanical properties were evaluated by means of nanoindentation, and the wear resistance was studied with pin-on-disk technique. The addition of Ag to the YSZ coatings led to decreased hardness, while the YSZ coatings deposited with Al presented an increased hardness. Finally, YSZ coatings deposited with aluminum and silver had the lowest friction coefficient, while Ag-YSZ coatings had a COF very similar to that obtained in YSZ coatings. The wear resistance test showed that YSZ coatings deposited with Al had lower volume loss compared to YSZ coatings deposited with Ag. The wear mechanism in the deposited coatings is analyzed.