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About J. Maharaja

Electroplating and Metal Finishing Technology Division, CECRI - Central Electrochemical Research Institute, Karaikudi – 630006, Tamilnadu, India

Choline chloride-Ethylene glycol mixture as electrolyte for nano crystalline Nickel electrodeposits

Fig. 1a: Comparison of conductivity of Ni(II) chloride dissolved in Ethaline complex

Nickel plating was carried out in stable Nickel ion based deep eutectic solvent (DES). The DES electrolyte stability and possible structure were explained by using Fourier Transform Infrared spectroscopy (FTIR) and Temperature Modulated Differential Scanning Calorimetry (TMDSC) techniques. The conductivity and electrochemical studies for choline based eutectic solvents were analyzed by conductivity cell and electrochemical impedance spectroscopy respectively. Higher current efficiency, thickness and hardness of Nickel were obtained by Pulse current electrodeposition when compared with Direct current electrodeposition. Crystallographic orientation and structural morphology were studied by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) respectively. Coated Nickel plate’s corrosion resistance and porosity properties were checked using potentiodynamic polarization and electrochemical impedance spectroscopy.


Effect of magnetic field on current efficiency and crystal orientation of NiCo alloy using pulse electrodeposition technique

Fig. 1: Electrodeposition process setup

The electrodeposition of NiCo alloy has been investigated in presence of various magnetic fields. The influence of superimposed magnetic field (0-0.5T) parallel to the electrode surface on current efficiency, surface morphology, preferred crystal orientation and electrochemical activity of Ni-Co alloy were studied. The maximum current efficiency was obtained by direct current at 100mA/cm2 with 0.4T. The optimized current density (100mA/cm2) was pulsed at four different frequencies (10, 25, 50 and 100Hz) with the same magnetic field (0.4T). However, the superimposition of magnetic field significantly favors the preferred crystal orientation of (220) phase. Pulsed current deposits exhibit single orientation of (220) at lower magnetic field (0.4T) whereas direct current deposition require higher magnetic field (0.5T). Tafel plot shows that electro-catalytic activity and corrosion resistance property has improved when the deposit is having a preferred orientation of (220).