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<p>This study presents a comprehensive examination of the microstructural features and high-temperature oxidation behavior of a CoNiCrAlY bond coat applied via Laser Powder Bed Fusion (LPBF) onto a Haynes 230 matrix. Upon isothermal exposure at 1050&#xa0;°C, the coating formed a continuous and adherent <i>α</i>-Al<sub>2</sub>O<sub>3</sub> scale, which increased in thickness from 1.11&#xa0;µm after 1&#xa0;h to 3.41&#xa0;µm following 200&#xa0;h of oxidation. This thermally grown oxide (TGO) morphology exhibited a marked improvement compared to the multilayered oxide scale—primarily composed of Cr<sub>2</sub>O<sub>3</sub> and spinel phases—that developed on the uncoated Haynes 230 substrate and was prone to spallation as its thickness expanded from 1.16 to 5.24&#xa0;µm. Microstructural and phase characterization indicated that a uniform distribution of the <i>β</i>-(Ni, Co)Al phase within the coating promoted the selective formation of the protective alumina layer. Additionally, the incorporation of Y<sub>2</sub>O<sub>3</sub> enhanced the adhesion of the oxide scale, effectively mitigating both inward oxygen diffusion and spallation at the oxide-coating interface. The growth kinetics of the TGO for both the coated and uncoated materials adhered to a parabolic rate law. Notably, the parabolic rate constant for the coating (<i>K</i><sub>p</sub> = 0.858) was significantly lower than that of the substrate (<i>K</i><sub>p</sub> = 1.419), underscoring its superior oxidation resistance. These results demonstrate that the LPBFed CoNiCrAlY coating markedly enhances the longevity of nickel-based superalloys under severe thermal conditions by facilitating the formation of a stable Al<sub>2</sub>O<sub>3</sub> scale and favorably influencing elemental interdiffusion. This work provides critical insights for the development of protective coatings for high-performance components and advances the application of additive manufacturing techniques in this domain.</p>

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The oxidation corrosion behavior of CoNiCrAlY bond coated on Haynes 230 matrix fabricated by laser powder bed fusion

  • 期刊论文

  • 发表日期：

    2026年4月9日

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  • Ziwei Cheng,
  • Lie Liu,
  • Cunliang Pan,
  • Nan Xiang,
  • Chenyang Jiang,
  • Hao Luo

摘要

This study presents a comprehensive examination of the microstructural features and high-temperature oxidation behavior of a CoNiCrAlY bond coat applied via Laser Powder Bed Fusion (LPBF) onto a Haynes 230 matrix. Upon isothermal exposure at 1050 °C, the coating formed a continuous and adherent α-Al2O3 scale, which increased in thickness from 1.11 µm after 1 h to 3.41 µm following 200 h of oxidation. This thermally grown oxide (TGO) morphology exhibited a marked improvement compared to the multilayered oxide scale—primarily composed of Cr2O3 and spinel phases—that developed on the uncoated Haynes 230 substrate and was prone to spallation as its thickness expanded from 1.16 to 5.24 µm. Microstructural and phase characterization indicated that a uniform distribution of the β-(Ni, Co)Al phase within the coating promoted the selective formation of the protective alumina layer. Additionally, the incorporation of Y2O3 enhanced the adhesion of the oxide scale, effectively mitigating both inward oxygen diffusion and spallation at the oxide-coating interface. The growth kinetics of the TGO for both the coated and uncoated materials adhered to a parabolic rate law. Notably, the parabolic rate constant for the coating (Kp = 0.858) was significantly lower than that of the substrate (Kp = 1.419), underscoring its superior oxidation resistance. These results demonstrate that the LPBFed CoNiCrAlY coating markedly enhances the longevity of nickel-based superalloys under severe thermal conditions by facilitating the formation of a stable Al2O3 scale and favorably influencing elemental interdiffusion. This work provides critical insights for the development of protective coatings for high-performance components and advances the application of additive manufacturing techniques in this domain.