S.R. Rajagopalan

Cyclic voltammetric behavior of certain copper-azole systems using carbon paste electrodes

Abstract Pure carbon paste electrodes and chemically modified carbon paste electrodes were used to evaluate the relative ability of certain azoles in inhibiting the corrosion of copper. Three different types of experiments were performed: (1) cyclic voltammetric studies of the azole-modified carbon paste electrodes in Cu(I)-containing supporting electrolyte; (2) cyclic voltammetric studies of pure carbon paste electrodes in supporting electrolytes containing both Cu(I) and the particular azole; (3) cyclic voltammetric studies using Cu(I)-modified and Cu(II)-modified carbon paste electrodes after dipping the electrodes in azole-containing solutions. The magnitude of the anodic dissolution of copper under these conditions is correlated to the corrosion inhibition efficiency. The corrosion rates measured for copper in sodium chloride in the presence of these azoles as inhibitors support this correlation.

A potential controlled transient technique for corrosion studies

Abstract A two-parameter (potential V0 and time constant τ potential controlled relaxation technique is described in this paper. The method consists in applying an exponentially increasing potential input V0(1-exp(−t/τ)) to the system under activation control and measuring the current-time response. The shape of the current-time transient changes in an interesting manner when τ is varied. A theoretical analysis of the transient has been carried out and it is shown that the method can be applied for the measurement of kinetic parameters of electrochemical reactions. The utility of the method for the measurement of polarisation resistance and double layer capacitance of corrosion systems is demonstrated in this paper. The method is applicable only to systems with slow electron transfer where mass transfer effects can be neglected. This, and the problem of eliminating noise in systems with low corrosion rate, are the two chief limitations of this technique.