Nickel was electroplated by using a jet flow device. For the normal Watts bath (containing 240g/
l of nickel sulfate, 45g/
l of nickel chloride, and 30g/
l of boric acid at pH=4), the maximum available current density (i
m) was found to be 90Amp/dm
2 at 45°C or 180Amp/dm
2 at 60°C when the electrolyte was supplied at a jet flow rate of 200cm/sec. (average value in nozzle).
At higher current densities, deposition of nickel was perfectly restrained.
The deposition rate attained to its maximum value (not limiting current value) at E
p (about -1.5V vs SCE), followed by a marked decrease at less noble potentials.
The effects of pH, flow rate, and nickel concentration on i
m were discussed with respect to codeposition rate of hydrogen and the resultant increase of pH in the diffusion layer around the cathode.
No remarkable difference in i
m was observed between the Watts bath and sulfamate bath, both of which were of the same concentration of nickel.
抄録全体を表示