Evolution of tribological properties of the composite coatings on AMG3 aluminum alloy during the atmospheric exposure

Abstract

The paper presents the results of an evaluation of the tribological characteristics of samples with composite coatings during 12 months of atmospheric corrosion. Composite coatings were obtained by treating oxide layer formed by plasma electrolytic oxidation (PEO) with fluoropolymers: superdispersed polytetrafluoroethylene (SPTFE) or polyvinylidene fluoride (PVDF), as well as a suspension of SPTFE in PVDF. It was found that the composite coatings formed in suspension with a ratio of PVDF to SPTFE 1:5 demonstrate the best tribological performance among the studied samples and characterizes by initial coefficient of friction 0.006–0.010. It is shown that samples with composite coatings have 1–1.5 orders of magnitude lower wear rate (9.7∙10⁻5–4.4∙10⁻4 mm3/(N·m)), in comparison with the PEO-treated sample (3.9·10⁻3 mm3/(N·m)).

Keywords

• aluminum
• protective coating
• plasma electrolytic oxidation
• composite coating
• tribology