ヒスチジン添加ピロリン酸浴からのCu-Zn合金電析物の構造と形態

抄録

Dense and continuous Cu-Zn alloy deposits were obtained from pyrophosphate baths containing histidine. Although neither Cu and Cu-Zn alloy deposits from baths without histidine nor Cu deposits from bath containing histidine showed a smooth surface morphology at 0.5A/dm² or above, Cu-Zn alloy deposits from baths containing histidine had a smooth surface at even higher current densities. This was because the partial current densities of Cu deposition were extremely low in the alloy baths containing histidine and did not attain the diffusion limited current at above 1.0A/dm². Smoother alloy deposits were obtained from baths containing Zn²⁺ ion concentrations of 0.05M or higher. Preferred orientation to the (110) facet was observed in the deposits obtained from baths with Zn²⁺ ion concentrations of 0.05M or higher at current densities of 1.0A/dm² or above. Both the smooth surface and the (110) preferred orientation of the deposits from the baths with high Zn²⁺ ion concentrations are attributed to high overpotentials. Both the Cu and Zn in the alloy deposits from the baths containing histidine were entirely in the metallic state, and formed an α solid solution and/or a β intermediate phase.