PHASE-STRUCTURE ANALYSIS OF BRASS BY ANODIC LINEAR-SWEEP VOLTAMMETRY

Anodic linear-sweep voltammetry (ALSV) was applied to electrodeposited alloy layers and to metallurgically obtained Cu-Zn alloys of different composition and structure. Metallurgically obtained samples covered the range of composition in which alpha, (alpha + beta), beta and (beta + gamma) intermediate phases were detected by X-ray. The ALSV of samples containing less than 30 wt % Zn exhibited a single peak at -0.08 to -0.1 V/SCE before massive dissolution, starting at about -0.05 V/SCE. The presence of the gamma-phase gave another peak at a significantly more negative potential (-0.25 to -0.35 V/SCE). The ALSV of electrodeposited alloys were significantly more complex than the former, depending on the deposition potentials, with peaks attributable to pure Zn, to the epsilon-phase, to the eta-phase as well as to the alpha-phase, present in most cases and dissolving at potentials similar to that of pure Cu. ALSV was shown to be a reliable and practical method for a fast determination of both the composition and the phase structure of electrodeposited brass.