Structural, Micromechanical and Tribological Characterization of Zn–Ni Coatings: Effect of Sulfate Bath Composition

International audienceZn and Zn-Ni alloy coatings were electrode-posited on mild steel from sulfate-based bath containing Sn as additive. The effect of Ni content on the microstructure, morphology, micro hardness and the tribological behavior of these coatings were studied and discussed. Adding Sn in the sulfate bath had a significant effect on the surface morphology, particularly on the Zn-8 wt% Ni coatings. By increasing the Ni concentration from 8 to 14 wt%, the X-ray patterns showed that the phase structure of Zn-Ni alloy coatings was changed from g-phase Ni 3 Zn 22 to c-phase Ni 5 Zn 21. The plastic deformation and delamination were found to be wear mechanisms for the investigated coatings. While the Zn-14 wt% Ni alloys had the best wear resistance, Zn films had the most severe wear volume loss and the highest friction coefficient