Embedding of hybrid MWCNT-Al2O3 particles in Ni matrix: structural, tribological and corrosion studies

N. Chronopoulou, E. Siranidi, A.M. Routsi, H. Zhao, J. Bai, A. Karantonis, E.A. Pavlatou

Surface and Coatings Technology (2018), 350, 672-685

Composite nickel coatings, were produced under direct (DC) and pulse current (PC) from a Watt's type bath, containing 0.5 g/L hybrid MWCNTs-Al2O3 , in presence and absence of additive Sodium Dodecyl Sulfate-SDS. Surface morphology, crystallographic orientation, wear resistance and corrosion resistance were studied. Micro-Raman measurements revealed that MWCNTs-Al2O3 is distributed at the whole depth of the cross-section profile analysis. The application of pulse current, favored a random crystallographic orientation of Ni crystallites with reduced grain sizes in comparison with pure Ni. The evaluation of the tribological data demonstrated that the composite coatings produced under pulse conditions in presence of additive, exhibited lower coefficient of friction, higher resistance to dry sliding accompanied by the presence of increased amounts of nickel oxide in wear tracks compared to pure Ni coatings. The behavior of pure and composite coatings in corrosive environment was evaluated by electrochemical impedance spectroscopy. It was found that composite coatings attained their corrosion resistance characteristics for 60 h in 0.6 M NaCl solution. Differences between pure nickel and composite coatings were attributed mainly to morphological differences rather than differences on corrosion performance.

doi: 10.1016/j.surfcoat.2018.07.034

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