Determination of the zinc and cadmium contents in low-alloyed tin

The method of anodic linear sweep voltammetry (ALSV) has been used to determine the content of Zn and Cd (up to 4% w/w) in eutectic type binary alloys with Sn. The alloy samples were prepared by casting. The effect of the type and the pH of the electrolyte, as well as of the sweep-rate on the dissolution of Zn and Cd from the alloy during an anodic potentinal-sweep was investigated. It was shown that ALSV is sensitive to low concentrations of both Zn and Cd in the investigated alloys, as well-defined peaks of the dissolution of the two metals were recorded before the massive dissolution of Sn commenced. Well-defined linear dependencies between the quantities of electricity under the dissolution peaks of Zn (Qzn) or Cd (Qcd) and the respective contents of the metals in the alloys were found. Intercepts at the abscissa were found in both investigated systems indicating the formation of solid solutions from which neither Zn nor Cd could be eluted. In both alloys, the smallest amount of the alloying component which could be detected was 0.25% (w/w). The application of the ALSV method has several advantages over other analytical methods: it is non-destructive as the dissolution involves only a very thin layer of the alloy; it requires simple and cheap instrumentation; it is fast and relatively sensitive. These make it suitable for routine analysis

Characterization of electrochemically formed thin layers of binary alloys by linear sweep voltammetry

It has been demonstrated that linear sweep voltammetry can be used as anin situ technique for characterization of electrodeposited thin layers of binary alloys. The anodic dissolution characteristics of linear sweep voltammograms are very sensitive to the type of electrodeposited alloy. If both metals do not passivate in the investigated solution, eutectic type alloys are characterized by two sharp dissolution peaks, indicating no miscibility between components in the solid phase. From the ideal solid solutions, components of the alloy dissolve simultnaeously, while in the case of intermediate phases and intermetallic compounds each phase, or compound, has its own peak of dissolution