The effect of molybdenum (Mo) concentrations on the mechanical and magnetic properties of electrodeposited Co rich ternary CoMoW thin films from citrate electrolytic bath

Abstract

Cobalt–Molybdenum-Tungsten (CoMoW) alloy thin films were prepared through an induced electroplating route from a citrate bath on the surface of the copper electrode at the controlled value of pH 8. The CoMoW thin films have been prepared by varying the Mo concentrations like 0.1, 0.2, 0.3 and 0.4 M at a deposition time of 30 minutes over a plating current potential of 40 mA / cm2. The electrodeposited CoMoW coatings have been investigated with the help of Field Emission Scanning Electron Microscopy (FESEM), powder crystal X-ray diffraction (XRD), Electrochemical studies (impedance and polarization) and Vibrating Sample Magnetometer (VSM) to reveal its respective microstructure-based information, mechanical and soft magnetic nature of the synthesized CoMoW thin layers. The CoMoW thin films of an HCP crystal structure have been attained. The induced electroplated condition such as Mo concentration has a significant impact on the crystal structure system, surface morphology, and soft magnetic performances. The crystalline size of the CoMoW thin layers has varied from 22.66 nm to 42.87 nm. The synthesized CoMoW thin layers were smooth, without cracks and had uniform morphology. All the electroplated CoMoW films have the highest Co content along with low Mo content (Co content gradually decreased while increasing the Mo content in the deposits) and thickness varied from 10 to 20 μm. Through the electrochemical investigation studies, it is concluded that the corrosion rate of CoMoW thin films was slightly increased by increasing the Mo content and the corrosion resistance varied from 80.2 KΩ to 92.7 KΩ. The CoMoW thin alloy films with higher Co content exhibited a lower coercivity value of 3.69 Oe and the saturation magnetization of 49.049 emu /cm2.