The Role of Microstructural Studies in Optimizing the Oxidation Resistance of High-Temperature Materials

摘要

The oxidation resistance of high temperature materials is, with few exceptions, determined by the nature of the reaction product formed by reaction between the material and the surrounding environment. Useful oxidation resistance requires that the reaction product grows slowly, remains adherent to the substrate material, and limits penetration of oxygen into the substrate. Traditionally, oxidation studies have emphasized characterization of the reaction products by optical metallography (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) to ascertain the techniques (alloying, coating, etc.) which result in the formation of the most protective reaction products. In recent studies, characterization by OM, SEM, and XRD has been supplemented by a variety oftechniques including transmission electron microscopy (TEM), surface analytical techniques, and laser raman spectroscopy. In this paper several examples are presented to show how this combination of techniques has lead to better understanding of the oxidation mechanisms of high-temperature materials and provided a basis for optimizing oxidation resistance.