Oxidation of high-temperature aerospace materials

Abstract

High-temperature processes and applications require their associated components to reach elevated temperatures that produce consequences on material properties. High-temperature oxidation is one such consequence and results from chemical reactions with the surrounding environment. Depending on severity, material performance can be degraded by surface recession or internal embrittlement, placing limits on use temperatures and times. Coatings, cooling schemes, or gas modifications are often employed to counteract these effects and provide a safer operational envelope. The purpose of this chapter is to provide a general description of the physical process, with specific examples chosen to highlight the prominent classes of high-temperature materials. It is hoped it will serve as a brief introduction and overview. For more detailed treatment of fundamentals and a broader list of topics, the reader is referred to classic texts (Kofstad 1988; Lai 1990; Birks, Meier et al. 2006; Young 2008). More detailed reviews can also be found in the latest edition of Shreir’s Corrosion, 2009. Here, dedicated chapters are found for defects and diffusion in oxide scales, stress effects, sulfidation, steam, and molten salt corrosion, steels, alumina and chromia scale forming alloys, coatings, intermetallics, and ceramics (Cottis et al. 2009).