Atomic Emission Spectroelectrochemistry: Real-Time Rate Measurements of Dissolution, Corrosion, and Passivation

Abstract

Atomic emission spectroelectrochemistry (AESEC) is a relatively novel technique that gives real-time elemental dissolution rates for a material/electrolyte combination, either reacting spontaneously or with electrochemical polarization. This methodology gives direct insight into questions such as how specific elements of an alloy interact with one another, or how specific additives in a surface treatment solution will affect different alloying elements or different phases. This paper discusses AESEC instrumentation and presents the basic quantitative relationships between the electrochemical and spectroscopic measurements. A wide range of applications are used to illustrate these relationships including the surface pretreatment of aluminum alloys (etching and deoxidation) and the passivation of Fe-Cr and Ni-Cr alloys. The focus is on the use of in-line inductively coupled plasma atomic emission spectroscopy (ICP-AES), although a brief discussion of similar techniques using in-line inductively coupled mass spectroscopy (ICP-MS) is included.