Analysis of chemical valence of the elements of the oxidized surface layer of a thermally sprayed Ni–Cr coating under fretting
1998; Elsevier BV; Volume: 106; Issue: 2-3 Linguagem: Inglês
10.1016/s0257-8972(98)00489-7
ISSN1879-3347
AutoresQingfu He, Shaozhong Guo, Wei Liu,
Tópico(s)Brake Systems and Friction Analysis
ResumoThe XPS technique was used to determine the valence of the elements in the oxidized surface layer of Ni–Cr coated axles under fretting. Oxides of Fe3+ and Cr3+ exist in the surface, and oxides of Fe2+, Fe3+ and Cr3+ are in the subsurface at a depth of 10 nm from the surface. The oxide films of Fe2O3–C2O3 and FeO–C2O3 play an important role in resisting fretting of the axles: avoiding metal-to-metal contact between the wheel hub and the axle; decreasing the friction coefficient; reducing adhesive wear and preventing axles from fretting fatigue fracture. However, fretting causes particles of oxide, and this hard oxide accelerates fretting wear.
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