High temperature corrosion characterization by the combined use of surface microsurgery and surface analysis

Abstract

AbstractCharacterization of both the chemical and physical nature of interactions at interfaces is crucial to mechanistic understanding of the behaviour of metallic and ceramic materials, including coatings, in aggressive environments at high temperatures. This can be achieved post exposure by the use of defined surface analytical techniques but is reliant upon the deployment of appropriate surface microsurgery procedures, such as metallography, fractography, taper section polishing, selective etching, complete dissolution, etc., for the preparation of surfaces prior to analysis. Recent studies undertaken at the Harwell Laboratory on the combined use of surface microsurgery and surface analysis in the characterization of high temperature corrosion attack are reviewed. These have aimed to improve the precision and the effectiveness of surface microsurgery procedures to ensure the optimum exploitation of the capabilities of surface analytical techniques, especially those in more common usage, such as scanning electron microscopy, electron probe microanalysis, laser Raman spectroscopy, secondary ion mass spectrometry, etc. Although most of the examples presented are of thick (> 1 μm) corrosion scales and of internal attack, several of the surface microsurgery procedures have relevance to the analysis of sub‐micron layers.