ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Comparative study of oxidation behavior of Fe–35Ni–22Cr and Fe–17Ni–18Cr alloys in dry air

Lamiaa Z. Mohamed, Sanaa S. Abd ElMoamen, and Fathy S. Ahmed

Mining, Petroleum, and Metallurgical Engineering Dept., Faculty of Engineering, CairUniversity, Giza, Egypt

E-mail: lamiaa.zaky@cu.edu.eg

Received: 16 May 2025  Accepted: 24 July 2025

Abstract:

Oxidation remains a critical degradation issue in marine, aircraft, land-based gas turbines, and industrial systems, primarily due to the combined effects of high operating temperatures and diverse fuel types. This study examines how Fe–35Ni–22Cr (F35N22C) and Fe–17Ni–18Cr (F17N18C) alloys oxidize at high temperatures when exposed to dry air for 50 h at 700 °C, 800 °C, and 900 °C. Oxidation kinetics were evaluated through weight change measurements, revealing parabolic behavior. The calculated activation energies were 300 kJ/mol for F35N22C and 277.9 kJ/mol for F17N18C. Corresponding parabolic rate constants at 700 °C, 800 °C, and 900 °C were 2.0 × 10⁻ ⁹, 2.0 × 10⁻ ⁹, and 1.0 × 10⁻ ⁶ g²/cm⁴·h for F35N22C, and 3.0 × 10⁻ ⁹, 1.0 × 10⁻ ⁹, and 4.0 × 10⁻ ⁷ g²/cm⁴·h for F17N18C. Phase identification and microstructural characterization were conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX). The formation of oxide scales rich in Fe₂O₃, Fe₃O₄, Cr₂O₃, NiCr₂O₄ spinel, and austenite contributed to the alloys’ oxidation resistance. SEM, spot-EDX, line scans, and elemental mapping of surface and cross-sections revealed the structural evolution of the oxide layers under different temperatures and durations. These findings enhance the understanding of protective scale formation and support the development of Fe-based alloys for high-temperature applications.

Keywords: High-temperature oxidation; Iron-nickel–chromium alloys; Activation energy; Oxide layers; Microstructure

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04274-3

Chemical Papers 79 (11) 7595–7615 (2025)