Development of corrosion-resistant Ni–Mo coatings from low-concentration bath: effect of magnetoconvection

Abstract

The phenomenon of magnetoconvection has been used effectively to improve the corrosion protection efficacy of Ni–Mo coatings from a low-concentration bath. Experimental studies demonstrated that magnetoelectrodeposited (MED) coatings developed under parallel () and perpendicular (?) magnetic field (B) are, respectively, about 4 and 7 times more corrosion resistant than electrodeposited (ED) alloy coatings, developed from the same bath. Properties of MED alloy coatings have been analysed by FESEM-EDS and XRD studies. An attempt has been made to understand changed properties of MED?(Ni–Mo) coatings considering B controlled diffusion of Ni2+ ions, and magnetic field-controlled limiting current density (i <inf>L</inf>) of metal ions in the bath. Ni–Mo coating of high corrosion resistance were developed from a low-concentration bath by proper manipulation of i <inf>L</inf> using induced B. © 2021 Institute of Materials, Minerals and Mining.