Abstract
For the purpose of investigating the brightening mechanism of bright copper cyanide bath, the polarization of cathodic deposit was measured, for which a Haring Cell improved so as to be suitable to cyanide complex was used. The result is as follows:
The polaization of cathodic deposit increases with an increase in copper concentration, with a decrease in free alkali cyanide concentration, with an increase in K+ concentration, and with an increase in temperature. It also increases with an addition in brightener when the current density is low, but decreases with an incrase in current density.
Comparing the above result with the range of brightness in the previous report, it is revealed that the factors that decrease the polarization would make the range of brightness broad.
Next, for the purpose of checking up the cause of improvement of brightening by potassium complex and potassium salt, the conductivity of plating bath was measured. As a result, it is recognized that the conductivity increases with the presence of K+, which, however, does not seem to be one of the leading factors.
