STP171: Structure of Oxides Formed on High-Temperature Alloys at 1500 F

    Radavich, John F.
    Research Associate, Purdue University, West Lafayette, Ind.

    Pages: 21    Published: Jan 1955


    Abstract

    The high-temperature resistance of iron-nickel-chromium alloys is determined for the most part by the structural, chemical, and physical nature of the oxides formed on the surface; the physical properties of the metal are influenced by, among other things, the phases precipitated in the metal, the number of cracks formed in the metal, type of oxides formed, and the healing influence of the oxide films on crack formation. The base metal and the surface state determine largely the rates of oxide formation and the diffusion of metal and oxygen through the initial oxide layer. Additions of cobalt, molybdenum, and tungsten to iron-nickel-chromium alloys produce alloys that have superior high-temperature properties. Although the process of high-temperature oxidation has been studied by various investigators, relatively little is known about the oxides formed, the mechanism of oxide formation, or the healing effects of various types of oxide layers. Because data on the type of oxides formed on high-temperature alloys are very meager, work was undertaken to study the oxide structures formed on various high-temperature alloys by means of electron microscopy, electron diffraction, and X-ray diffraction.


    Paper ID: STP46829S

    Committee/Subcommittee: E01.01

    DOI: 10.1520/STP46829S


    CrossRef ASTM International is a member of CrossRef.