Influence of CH3SO3H and AlCl3 in direct and pulse current electrodeposition of trivalent chromium

Comparison of direct and pulse current electrodeposition of the trivalent chromium from urea formic acid as a complexing agent was studied in detail. The influences of CH3SO3H and AlCl3 on the properties of the deposit were also studied. The presence of CH3SO3H exhibits higher current efficiency and better corrosion resistance because of its higher hydrogen overpotential. The pulse current electrodeposition leads to growth of beta-Cr. The corrosion studies were conducted by potentiodynamic polarisation and electrochemical impedance spectroscopy. The morphology of the deposits was characterised by scanning electron microscopy (SEM) and X-ray diffraction.