Electrodeposition And Properties Of Ni-W, Co-Ni-W Alloys

The Ni-W and Co-Ni-W amorphous alloys have been prepared on the Cu substrates by electrodeposition method using citric acid-citrate as their complexing agent. The structure of the different alloys was examined using X-ray diffraction (XRD). The surface morphology was analyzed by SEM. The deposition rate and current efficiency have been investigated as a function of the pH, current density and plating bath temperature. The results show that the samples are amorphous at pH lower than 9 and the samples have a nanocrystalline structure at pH 9. The deposition rate and current efficiency reaches maximum when pH is 8. EDS was used to study W content of the different alloys. The results show that with the increase of the pH, the W content decrease and the highest W content is 37at. %.The microhardness of alloys prepared with different pH values, different current densities, and different plating bath temperatures have been studied. And the magnetic peoperties of the alloys with different pH values have been measured. Correlations between the structure and the properties have been discussed. The results show that the microhardness of the Co-Ni-W samples reaches the maximum of 10.5 GPa when pH is 9 and the coercivity reaches the minimum of 23 Oe when pH is 6.