シアン化銅メッキ液添加剤の陰極分極に及ぼす影響について
光沢平滑シアン化銅メッキに関する研究 (第2報)
1967 年 18 巻 4 号 p. 146-155
詳細
1967 年 18 巻 4 号 p. 146-155
In the previous paper, the author reported the relationship between additives and their brightening effects on copper cyanide plating baths. The results showed that the additives yielding bright copper deposits included the compounds containing sulfur such as thiosulfate, thiocyanide, xanthogenate, etc. and the inorganic compounds containing Pb, Te, etc.
In this paper, for the purpose of investigating the brightening mechanism of these additives, the effects of the above additives, bath compositions, and operating conditions on the cathode polarization were determined.
The results were summarized as follows:
1) The cathode polarization of copper deposition decreased with the increase of metallic copper concentration, decrease of tree cyanide concentration, elevation of bath temperature, and with agitation. However, little effects were given by employing PR (Periodic Reverse) current on the cathode polarization. Then, there would be very little cathode polarization in reverse current.
2) In the baths containing lead compound, the cathode polarization increased at low current density. Then, the deposition potential of copper would be elevated owing to the deposition of lead. On the other hand, in the baths containing a large amount of tellurium, the cathode polarization slightly decreased. Hence, the effects of these additives on brightness would be due to the deposition of these elements together with copper.
3) In the baths containing the above sulfur compounds, the cathode polarization remarkably decreased and more and more decreased with air agitation and employing of PR current at high operating temperature. Hence, the beneficial brightening effects of sulfur compounds would be due to the grain refining of crystals by the deposition of a small amount of sulfur together with copper.
4) The addition of organic compounds had little effects on the cathode polarization. However, the addition of a large amount of nonion surface active agents exerted a slight decrease in cathode polarization and somewhat improved the brightness of copper deposits.
