ELECTRODEPOSITION OF NICKEL-VANADIUM PENTOXIDE COMPOSITE AND ITS CORROSION BEHAVIOR

Dispersion-strengthened nickel was produced by an electro-codeposition technique using a nickel fluoborate electrolyte containing vanadium pentoxide (V2O5) particles in suspension. The effects of particle size, particle concentration in the bath, current density, pH and temperature on volume percent (vol.%) incorporation of V2O5 particles in the composite were investigated. Corrosion behaviour of the composite in 5% sodium chloride (NaCl) solution was also examined and compared with that of mild steel and nickel deposits. It was found that the vol.% incorporation of V2O5 particles in the composite increased with increasing V2O5 content in the bath and with increasing current density. An optimum V2O5 incorporation (12.6 vol.%) was possible by operating the bath at 6.0 amp dm(-2), at pH 3.0 and at 50 degrees C. The results of corrosion studies reveal that the composite confers on steel an improved protection against corrosion in NaCl medium. Whereas the corrosion resistance of the composites is inferior to that of nickel deposits in NaCl solution of pH 3.0, about the same protection is offered in NaCl solution of pH 6.5.