Advanced composite coating by electrodeposition technique

Abstract

This work aims to prepare Ni–RuAl composite coatings from Watts’ solution containing suspension of the single phase powder of the intermetallic compound RuAl. The chemical composition, phase structure and surface morphology of pure Ni and Ni–RuAl composite coatings are investigated using energy dispersive analyser system (EDX), X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The microhardness and oxidation resistance of Ni–RuAl composite coatings in comparison with pure Ni are evaluated. The corrosion behaviour for both of Ni and Ni–RuAl deposits is evaluated by polarisation curves in 3·5% NaCl solution. The results reveal that the content of RuAl in the Ni matrix is a function of applied current density and concentration of RuAl powder in the plating bath. Moreover, the presence of RuAl improves the oxidation and corrosion resistance of Ni coatings. The microhardness of composite coatings increases with the increasing content of the RuAl particles in the deposit.

Keywords:

• RUAL SINGLE PHASE
• NI ELECTRODEPOSITION
• COMPOSITE COATINGS
• OXIDATION RESISTANCE