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<p>To improve the melt purity of DD6 single-crystal superalloy and mitigate interfacial reactions with Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub> ceramics during casting, an anti-erosion enhancement strategy that combines sintering parameter optimization with surface coating modification is proposed. By systematically tailoring the sintering temperature and impregnation–coating process, Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub> ceramics with both superior mechanical properties and refined surface quality were fabricated. On this basis, the high-temperature wetting behavior and interfacial reaction mechanisms between ceramics with different surface conditions and DD6 alloy melt were investigated. Results show that sintering at 1260&#xa0;°C yields a dense and homogeneous microstructure with a porosity of 30.5% and a flexural strength of 12.75&#xa0;MPa, ensuring thermal stability and structural integrity. The introduction of a dense Al<sub>2</sub>O<sub>3</sub> surface coating further reduced surface porosity, suppressed melt infiltration, and retarded interfacial reactions. High-temperature melting tests revealed that the erosion layer thickness decreased from 150 to 200&#xa0;µm for the uncoated ceramics to ~ 100&#xa0;µm for the coated one. Wetting measurements showed that the contact angle between the melt and the ceramic surface increased from 126.15° to 129.77° after coating treatment, indicating weakened wettability. Interfacial characterization confirmed the formation of HfO<sub>2</sub> as a reaction product, evidencing a reactive wetting mechanism. Overall, the synergistic optimization of sintering parameters and surface densification significantly enhances the high-temperature corrosion resistance and service stability of Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub> ceramics, offering robust engineering support for their application in clean melting of advanced superalloys.</p>

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Synergistic sintering and surface coating design for high-temperature wettability and interfacial reaction control of Al2O3–SiO2 ceramics in DD6 superalloy melting

  • 期刊论文

  • 发表日期：

    2026年3月14日

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  • Qian Dang,
  • Shan-Shan Wang,
  • Yun-Fei Zhang,
  • Chi Zhang,
  • Wan Zhang,
  • Guo-Huai Liu,
  • Zhao-Dong Wang

摘要

To improve the melt purity of DD6 single-crystal superalloy and mitigate interfacial reactions with Al2O3–SiO2 ceramics during casting, an anti-erosion enhancement strategy that combines sintering parameter optimization with surface coating modification is proposed. By systematically tailoring the sintering temperature and impregnation–coating process, Al2O3–SiO2 ceramics with both superior mechanical properties and refined surface quality were fabricated. On this basis, the high-temperature wetting behavior and interfacial reaction mechanisms between ceramics with different surface conditions and DD6 alloy melt were investigated. Results show that sintering at 1260 °C yields a dense and homogeneous microstructure with a porosity of 30.5% and a flexural strength of 12.75 MPa, ensuring thermal stability and structural integrity. The introduction of a dense Al2O3 surface coating further reduced surface porosity, suppressed melt infiltration, and retarded interfacial reactions. High-temperature melting tests revealed that the erosion layer thickness decreased from 150 to 200 µm for the uncoated ceramics to ~ 100 µm for the coated one. Wetting measurements showed that the contact angle between the melt and the ceramic surface increased from 126.15° to 129.77° after coating treatment, indicating weakened wettability. Interfacial characterization confirmed the formation of HfO2 as a reaction product, evidencing a reactive wetting mechanism. Overall, the synergistic optimization of sintering parameters and surface densification significantly enhances the high-temperature corrosion resistance and service stability of Al2O3–SiO2 ceramics, offering robust engineering support for their application in clean melting of advanced superalloys.