Comparative study of protective nickel–tungsten deposit behavior obtained by continuous and pulsed currents from citrate–ammonia media

A comparative study of protective Ni–W deposit behavior obtained by continuous (cc) and pulsed (pc) currents from citrate–ammonia media on copper surface was presented. Effects of electroplating process on microstructures, in terms of crystallization, proportion and grain size were investigated using SEM/EDS and XRD. The results show that Ni–W morphology obtained by (cc) and (pc) was quite different; it changed from rigorous and irregular to smooth and granulate. Corrosion mechanisms and stability in 10 h of immersion into 3% NaCl of various treated-coatings were discussed in the consideration of electrical conductivity, microhardness, porosity and inhibition efficiency.

► Ni–W coatings obtained with continuous current were smooth and irregular crystals.
► Ni–W pulsed electrodeposited films were homogeneous and in granulated amorphous form.
► Ni–W deposits improve electrical, mechanical and electrochemical properties of Cu.
► Ni–W films obtained by pulsed current showed better long-term stability into 3% NaCl.