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

摘要

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.