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<p>Highly porous nickel-based superalloys are appearing as promising materials for high-temperature applications such as gas turbine sealing systems and membrane-assisted steam methane reforming. Recently (Bętkowska et al. Sci Rep 15:598, 2025), we reported the fabrication and mechanical performance of highly porous Hastelloy-X (H–X) with spherical open porosity of up to 70 vol.%. Here, the high-temperature oxidation behavior of this material is investigated for the first time. Porous H–X alloys produced using a space holder technique were exposed to air at 1000&#xa0;°C for up to 100&#xa0;h. Oxidation kinetics were evaluated by thermogravimetric measurements, while the morphology and composition of the oxide scales were analyzed using SEM/EDS and XRD. The oxide scale was found to consist primarily of NiO, Cr<sub>2</sub>O<sub>3</sub> (with incorporated Mn ions) and (Ni,Fe)Cr<sub>2</sub>O<sub>4</sub> spinel. All porous samples showed mixed linear–parabolic oxidation kinetics, with mass gain increasing with increasing porosity. In contrast, the counterpart produced without space holder particles showed a mass loss after 100&#xa0;h under identical conditions. This behavior is attributed to the highly developed internal surface area of the porous structures, which promotes the formation of a protective oxide scale. The role of discontinuously precipitated M<sub>23</sub>C<sub>6</sub>/M<sub>6</sub>C carbides in the oxidation behavior of the porous alloy is also discussed. These results provide new insights into the oxidation mechanisms of highly porous nickel-based superalloys and highlight their potential as high-temperature oxidation-resistant materials.</p>

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Highly Porous Hastelloy-X Nickel Superalloy Produced by a Space Holder Approach: Oxidation Behavior at 1000 °C

  • 期刊论文

  • 发表日期：

    2026年5月11日

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  • Adelajda Polkowska,
  • Ewa Rząd,
  • Marcin Podsiadło,
  • Aleksandra Bętkowska,
  • Wojciech Polkowski

摘要

Highly porous nickel-based superalloys are appearing as promising materials for high-temperature applications such as gas turbine sealing systems and membrane-assisted steam methane reforming. Recently (Bętkowska et al. Sci Rep 15:598, 2025), we reported the fabrication and mechanical performance of highly porous Hastelloy-X (H–X) with spherical open porosity of up to 70 vol.%. Here, the high-temperature oxidation behavior of this material is investigated for the first time. Porous H–X alloys produced using a space holder technique were exposed to air at 1000 °C for up to 100 h. Oxidation kinetics were evaluated by thermogravimetric measurements, while the morphology and composition of the oxide scales were analyzed using SEM/EDS and XRD. The oxide scale was found to consist primarily of NiO, Cr2O3 (with incorporated Mn ions) and (Ni,Fe)Cr2O4 spinel. All porous samples showed mixed linear–parabolic oxidation kinetics, with mass gain increasing with increasing porosity. In contrast, the counterpart produced without space holder particles showed a mass loss after 100 h under identical conditions. This behavior is attributed to the highly developed internal surface area of the porous structures, which promotes the formation of a protective oxide scale. The role of discontinuously precipitated M23C6/M6C carbides in the oxidation behavior of the porous alloy is also discussed. These results provide new insights into the oxidation mechanisms of highly porous nickel-based superalloys and highlight their potential as high-temperature oxidation-resistant materials.