Add time:08/15/2019         Source:sciencedirect.com

Cu-Zn alloy deposition processes from glucoheptonate baths have been studied by analysing the composition of deposits, measuring the current density-potential curves and measuring the absorption spectra of the bath. Alloying interactions during codeposition were discussed on the basis of partial current density-potential curves of each component and absorption spectra of the bath. Baths adjusted to pH 4.5 and 10.0 were studied. From the pH 4.5 bath, only copper was deposited at current densities below 0.5 A dm−2. At current densities above 0.5 A dm−2, however, the zinc content of deposits increased rapidly with increasing current density. The current density-potential curve of the pH 4.5 alloy bath was almost an algebraic sum of those of the individual baths and did not exhibit any alloying interactions. In contrast, the compositions of deposits from the pH 10.0 bath were almost constant over a wide range of current density from 0.5 to 2.0 A dm−2, and zinc was codeposited even at low current densities below 0.2 A dm−2. The partial current density-potential curve of copper exhibited a less noble (negative) shift with an addition of Zn2+. This less noble shift is attributed to the formation of a more stable Cu2+ complex species, on the basis of the change in the absorption spectra. However, the partial current density-potential curve of zinc was essentially unchanged in the presence of Cu2+ except that the limiting current was increased. The difference in the limiting current was ascribed to the difference in the rate of mass transfer due to H2 evolution.

We also recommend Trading Suppliers and Manufacturers of SODIUM GLUCOHEPTONATE (cas 10894-62-9). Pls Click Website Link as below: cas 10894-62-9 suppliers