Identification of intermetallic compounds in thin layers of electrodeposited Cu–Cd alloys using electrochemical techniques

Abstract

An attempt was made to analyse the phase structure of thin layers of electrodeposited Cu–Cd alloys using anodic linear sweep voltammetry combined with a potentiostatic pulse technique (ALSV–PPT). The results were compared with data obtained using conventional techniques for phase structure analysis. It was found that application of the conventional X-ray technique (Guinier analysis) is limited, because the grain size of the alloy constituents is too small for compounds to be revealed by X-ray peaks. Electrodeposited alloys could be successfully analysed using that method only after subsequent thermal treatment. Diffraction patterns from transmission electron micrographs of very thin foils (of the order of 20–50 nm) of electrodeposited 75Cd–25Cu (at.-%) alloy revealed the presence of CuCd3 intermetallic compound having a grain size of ~20 nm. By comparing all the results, the distribution of the various intermetallic compounds present at various stages in the electrodeposition of thin (up to 10 μm) layers of Cu–Cd alloys could be established. Combined ALSV–PPT was found to be more sensitive than either of the other methods employed. MST/1206.