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 CH 3 SO 3 H and AlCl 3 on the properties of the deposit were also studied. The presence of CH 3 SO 3 H exhibits higher current efficiency and better corrosion resistance because of its higher hydrogen overpotential. The pulse current electrodeposition leads to growth of β-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.