Structural characterization of iron oxide grown on 18% Ni-Co-Mo-Ti ferrous base alloy aged under superheated steam atmosphere

• Published in: International journal of advanced manufacturing technology Vol. 119; no. 3-4; pp. 1757 - 1768
• Main Authors: de Souza Martins Cardoso, Andréia, da Igreja, Hugo Ribeiro, Garcia, Pedro Soucasaux Pires, Chales, Rodrigo, Pardal, Juan Manuel, Tavares, Sérgio Souto Maior, da Silva, Maria Margareth, Paesano, Andrea, Pichon, Luc
• Format: Journal Article
• Language: English
• Published: London Springer London 01-03-2022; Springer Nature B.V; Springer Verlag
• Subjects: Aerospace engineering; Aging; CAE) and Design; Computer-Aided Engineering (CAD; Corrosion; Emission analysis; Engineering; Engineering Sciences; Enrichment; Ferrous alloys; Glow discharges; Heat treatment; Hematite; High temperature; Hydrogen embrittlement; Industrial and Production Engineering; Iron oxides; Isotopic enrichment; Maraging steels; Mechanical Engineering; Mechanical properties; Media Management; Microscopy; Military applications; Molybdenum; Nickel; Nuclear engineering; Optical emission spectroscopy; Optical microscopy; Original Article; Oxide coatings; Photoelectrons; Physics; Rocket engines; Spectrum analysis; Structural analysis; Titanium; X ray photoelectron spectroscopy; 18% Ni-Co-Mo-Ti ferrous base alloys; Maraging steel; Hydrogen embrittlement; Characterization oxide layers; 18% Ni-Co-Mo-Ti Ferrous base alloys
• DOI: 10.1007/s00170-021-08263-0
• EISSN: 1433-3015
• ISSN: 0268-3768

18% Ni-Co-Mo-Ti ferrous base alloys are special materials, widely used in the industry of isotopic enrichment after specific annealing and aging thermal treatment. The desirable high mechanical properties can then be attained by adequate aging heat treatment, answering the structural materials specifications required by defense applications in aerospace and nuclear engineering. For instance, the isotopic enrichment, in rocket engine envelope application, when associated with high temperature and chemical residues like acidic solutions, can induce corrosion and hydrogen embrittlement in martensitic microstructure. In order to limit these corrosion and hydrogen embrittlement phenomena, adherent and protective layers of iron oxides can be grown on the material’s surface by performing aging treatment in an adequate atmosphere. Due to its application in strategic areas, the characterization of these oxide layers in maraging steels is of importance as well as the understanding of their growth kinetics. For this purpose, several techniques, such as optical microscopy (OM), scanning electron microscopy (SEM), glow discharge optical emission spectroscopy (GDOES), microabrasive wear testing, hardness, grazing incidence X-ray diffraction (GIXRD), and X-ray photoelectron spectroscopy (XPS), have been performed for chemical and structural characterization of the oxide films formed after vapor exposed thermal aging at 510℃. The oxide layer consists of two sub-layers composed by magnetite (
Fe
3
O
4
) and an external layer of hematite (
Fe
2
O
3
). A thick interface between the oxide layer and the bulk is enriched in Ti and Mo, whereas the analyses of deep bulk material show an enriched area with Ni and Co.