Dry sliding tribological behaviors of nanocrystalline Cu-Zn surface layer after annealing in air

Powder compacting process was employed to fabricate nanocrystalline Cu-Zn alloy layer on the surface of coarse-grained copper matrix. The tribological behaviors of nanocrystalline surface layer after annealing in air were investigated. Sliding wear tests were performed on a pin-on-disk test machine under dry conditions. The morphologies and element chemical states of the worn surfaces were examined with scanning electron microscopy (SEM) and X-ray photoelectron spectrometer (XPS), respectively. It was found that 300 degreesC annealed nanocrystalline Surface layer presented Optimum mechanical and tribological properties. The 300 degreesC annealed nanocrystalline surface layer showed remarkably high load-bearing capacity. A tribo-surface film almost covering entire worn surface was observed at applied load range from 60 to 160 N. This tribo-surface film was found to comprise elements from both the sliding counterparts. XPS analysis revealed the enrichment of nanocrystalline ZnO in the tribo-surface film, which can contribute to reduce friction coefficient and form a more steady and long life tribo-surface film. (C) 2003 Elsevier B.V. All rights reserved.