Synergistic mechanism of the fretting wear resistance of Fe2O3/Ag nanostructured coatings prepared by sliding friction and magnetron sputtering

Abstract

The synergistic effect of the hard/soft phases of a material is potentially valuable and significant for improving wear resistance. Given this, a method for preparing Fe2O3/Ag nanostructured coatings, in which reciprocating sliding friction is used to prepare nano-Fe2O3 coatings and magnetron sputtering is used to prepare nano-Ag coatings, is proposed. The fretting wear test using a SiC ball as the friction pair shows that a large amount of oxide accumulates on the friction pair surface of the substrate, while that of the coating is smooth, and the coating greatly improves the wear resistance of the sample. In particular, the Fe2O3/Ag coating has better fretting wear resistance, and the wear rate is as low as 7.03 × 10−6 μm3N−1μm−1. The excellent tribological properties of Fe2O3/Ag nanostructured coatings at room temperature are derived from the Ag–Fe2O3 nanocomposite layer with a Ag composition gradient, which is formed by Ag nanoparticles gradually penetrating into the Fe2O3 layer under the normal load produced during fretting wear. Furthermore, the Ag/Fe2O3 semi-coherent interface, which is induced between Ag and Fe2O3 nanoparticles under fretting wear, endows the composite layer with excellent thermal and mechanical stability. This design idea of using a fretting wear load to prepare composite coatings with the synergistic effect of hard and soft phases to strengthen the wear performance of a workpiece also provides a reference for the preparation of other hard/soft heterogeneous coatings.