The Anodic Dissolution of Binary Alloys

Abstract

A method for calculating the anodic polarization curves of binary alloys from those of their components is presented. Heterogeneous alloys can be treated as simple galvanic couples, but homogeneous alloys are subject to a modification of Tammann's concept of surface enrichment. Potentiostatic anodic polarization curves are used to compare the calculated and experimental curves. Data are presented for the tin‐zinc, cadmium‐zinc, iron‐chromium, titanium‐chromium, and iron‐titanium systems.

Effect of carbon on corrosion behaviour of Fe3Al intermetallics in 0.5 N sulphuric acid

“…They have reported the i pass value of Fe is higher than that of Al, which is contrary to the present study. Nevertheless, the present value of i pass is well in agreement with that reported by Steigerwald and Greene for Fe (99.94%) [16].…”

Electrodeposition and Characterization of Alloys and Composite Materials

“…This is not the case in reality, since the diffusion coefficients at room temperature may be considerably larger than the extrapolated ones (in the case of Cu, monovacancies cannot account for this mechanism, but divacancies, with D ¼ 1.3 Â 10 À12 cm 2 s À1 , may make the mechanism operative) [40]. There is a significant inconsistency in the results reported earlier from investigations of the mechanism of alloy dissolution, particularly for results obtained with bulk alloy samples [39][40][41][42][43][44][45][46][47][48]. For example, for one and the same system (Cu-Ni) it was found both that components dissolve simultaneously [44] and that Ni dissolves preferentially [43].…”

“…Using this method it was possible to determine the thickness of the coating and that of the intermediate layer between the coating and substrate, as well as to obtain data about the phase composition of the coating. Since then, electrochemical techniques have been extensively used for investigating processes of alloy dissolution [39][40][41][42][43][44][45][46][47][48]. In all of these cases bulk alloys were investigated, and the discrepancies between the obtained results were significant.…”

Leachability of Lead from Selected Copper-Base Alloys

“…It is known metallurgically that the bulk of the lead in these brasses is not dissolved in the copper as in a homogeneous alloy but rather distributed in grain boundaries to form a heterogeneous alloy. 1 A heterogeneous alloy can be considered a galvanic couple in which electrical connection is made by direct contact. A look at the galvanic series of metals shows that lead is more active than the other constituents of most brasses and, thus, could be selectively leached in corrosive environments.…”