A. Survila et al., CURRENT OSCILLATIONS OBSERVED DURING CODEPOSITION OF COPPER AND TIN FROM SULFATE-SOLUTIONS CONTAINING LAPROL 2402C, Electrochimica acta, 43(8), 1998, pp. 909-917
Current oscillations have been found during codeposition of copper and
tin from sulfate solutions containing the surface-active substance (S
AS) Laprol 2402C in the region of negative slope in the voltammogram.
These phenomena are interpreted in terms of the transition from one st
able state to another. The effective rate constant for the latter stat
e was suggested to be significantly lower due to the inhibiting adsorp
tion of SAS. The necessity of two conditions for oscillations to occur
was confirmed, ie the existence of a negative faradaic impedance (Z(F
) < 0) and the fulfillment of the inequality R-s > \Z(F)\ (R-s is the
external resistance including the ohmic cell resistance). The interpla
y between the oscillation phenomena and the phase constitution of the
alloys deposited is discussed. (C) 1997 Elsevier Science Ltd. All righ
ts reserved.