MÖssbauer Effect and Iron Corrosion Kinetics

Abstract

THE formation and maintenance of a protective film on the surfaces of mild steel equipment used to generate steam are important for safe and economical operation. Knowledge of the kinetics of the film's growth may lead to an understanding of the mechanisms of the process, and various properties have been measured: weight increase, detachment by chemical action and chemical analysis of the film, the movement of radioactive and other markers¹, and measurements of the rate of effusion through the walls of the vessel of hydrogen produced in the reaction². Most of these methods involve assumptions about the nature and composition of the materials encountered, or else require a series of measurements on a number of different samples of identical nature. The use of the Mossbauer effect in iron-57, though well known³, has so far been little used for corrosion studies. This method has several advantages: for example, different iron oxides and other likely corrosion products can usually be identified⁴ from a few milligrams.