The Effect of Tungsten Content on Nanocrystalline Structure of Ni-W Alloy Electrodeposits
The effects of tungsten content on the nanocrystalline structure of Ni-W alloy electrodeposits were investigated. Direct current electrodeposition was conducted with various W mole fractions in a nickel sulfate solution containing citric acid as a complexing agent. Current efficiency was an almost constant value of 52% up to W mole fraction of 0.58. However, it was sharply decreased owing to severe H2 evolution with increasing cathode overvoltage at a W mole fraction higher than 0.74. The X-ray diffraction peak was decreased and broadened with increasing W content, and an amorphous pattern appeared clearly at 49 wt.% W. It was confirmed that Ni-W alloy deposit was transformed from crystalline to amorphous structure between 41 and 49 wt.% W. This result was also verified through a TEM analysis.
Hyung Sun Kim, Yu Bao Li and Soo Wohn Lee
W. S. Hwang and W. S. Cho, "The Effect of Tungsten Content on Nanocrystalline Structure of Ni-W Alloy Electrodeposits", Materials Science Forum, Vols. 510-511, pp. 1062-1065, 2006