Development and tribological characterisation of nanostructured Zn-Ni and Zn-Co coatings: a comparative study |
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| Authors: | F Nasri M Zouari M Dammak F Vacandio M Eyraud |
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| Affiliation: | 1. Laboratory of Electromechanical Systems (LASEM), National Engineering School of Sfax, University of Sfax, Sfax, Tunisia;2. Laboratory of Divided Materials, Interface, Reactivity, Electrochemistry (MADIREL), Aix-Marseille University, Marseille, France |
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| Abstract: | Zn-Ni and Zn-Co alloy coatings were electrodeposited on mild steel from sulphate-based baths. The morphology, microstructure, microhardness and tribological behaviours of the coatings have been studied and discussed. While the Zn-5wt-% Co layers presented a nanocrystalline simple nodular structure (45?±?5?nm), the Zn-14wt-% Ni showed a particular structure called cauliflower morphology (30?±?7?nm). The X-ray diffraction analysis showed that each of the electrodeposits was formed from zinc solid solution with a uniform zinc-cobalt intermetallic phase γ2 (CoZn13) for Zn-5wt-% Co alloy. However, a single γ-phase (intermetallic compound Ni5Zn21) was presented for the Zn-14wt-% Ni alloys. The Zn-14wt-% Ni films were found to be harder and rougher than the Zn-5wt-% Co layers. Plastic deformation and oxide layers production were the main wear mechanisms for the investigated coatings. The Zn-14wt-% Ni coatings were found to have the best wear resistance due to their microhardness and particular structure. |
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| Keywords: | Intermetallic Zn alloy coatings nanocrystalline microstructure friction and wear behaviours |
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