Modelling of Electrochemical Noise Due to the Activation-Controlled Dissolution of Metals

Abstract

This paper considers the noise expected to be generated by the activation-controlled anodic dissolution of a pure metal An atomistic model of this process suggests that dissolution will occur in bursts, as ledges are ‘unlocked’ by the dissolution of a ledge atom, and then the exposed kink atoms dissolve rapidly. Examination of the statistics of this model suggests that the resultant electrochemical noise will have the characteristics of shot noise, but with the magnitude of the charge carrier being a function of the length of ledge that is dissolving. For this model the current noise power is proportional to the average number of atoms in each ledge and the total current flowing. For typical ledge lengths the charge in each pulse is such that the noise level will be low relative to values that are normally measured for real corroding systems, and this source of noise should be regarded as a lower bound for the possible noise characteristics.