This study concerns mechanism and kinetics of isothermal oxidation of four Fe-Cr-Al-Ti ferritic alloys in the range 700 °C to 900 °C for up to 50 hours in air. These four alloys with nominal compositions of 83.0Fe-13.5Cr-2.0Al-0.5Ti (alloy A), 79.0Fe-17.5Cr-2.0Al-0.5Ti (alloy B), 75.0Fe-21.5Cr-2.0Al-0.5Ti (alloy C), and 71.0Fe-25.5Cr-2.0Al-0.5Ti (alloy D) each with 1.0 wt pct nano-Y2O3 dispersion were synthesized by mechanical alloying and sintering at 1000 °C by hot isostatic pressing, high pressure sintering, hydrostatic extrusion and pulse plasma sintering techniques. A detailed characterization of the phase aggregate, microstructure and micro-composition of the oxide scale was carried out by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy, respectively. Oxidation kinetics appear to follow a parabolic rate with an activation energy of 135 to 234 kJ/mol, which depend on alloy composition (i.e., Cr content). Oxidation mostly occurred by counter-ionic diffusion of oxygen from air to the interior and cations (Cr+3 or Fe+3) from the bulk toward the surface. Alloy D sintered by hot isostatic pressing offered the highest resistance to oxidation. [ABSTRACT FROM AUTHOR]
Copyright of Metallurgical & Materials Transactions. Part A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
