Tribological Properties of Tin-Zinc Hybrid Coating on Bronze in Lubricated Condition

Abstract

Tribological properties of tin (Sn)-zinc (Zn) hybrid coating on bronze were evaluated in lubricated condition mating with a chromium alloy steel (Japanese Industrial Standards, JIS SUJ2) flat surface. A shot peening technique using Sn and Zn fine powders as the impact media was applied to the coating process. The resulted coating film thickness was approximately 1-2 µm. Tribological properties of mono-layered coating showed that the friction coefficient and the wear loss were considerably smaller than those of the bronze and that the transfer layer morphology was different depending on the coating material. Further decrease of the friction coefficient was found on the hybrid Sn-Zn coating surface and Zn transfer layer accompanying with oxygen reduced. Therefore, it is concluded that hybrid Sn-Zn coating is effective means to improve the tribological properties of bronze surface.

Keywords

• tin
• zinc
• hybrid coating
• friction coefficient
• shot peening
• transfer layer