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<p>The manufacturing process of existing TiAl matrix composites relies heavily on expensive Ti powders. Additionally, traditional methods for preparing compound powders are subject to technical limitations, including excessively high reaction temperatures and particle agglomeration. To address these shortcomings and effectively convert low-cost TiO<sub>2</sub> into compound powder, a new method for preparing Al<sub>2</sub>O<sub>3</sub>/TiAl composite powders using a ternary molten salt-assisted thermite reduction of TiO<sub>2</sub> was proposed. And also we studied the regulatory mechanisms of process parameters, the molten salt medium, and the sintering process on the phase composition and microstructure of the powder. Dense <i>γ</i>-TiAl/<i>α</i><sub>2</sub>-Ti<sub>3</sub>Al dual-phase Al<sub>2</sub>O<sub>3</sub>/TiAl composite powders were successfully synthesized under the conditions of an Al/TiO<sub>2</sub> molar ratio of 1.628, a reaction temperature of 1000&#xa0;°C for 2&#xa0;h, and a sintering temperature of 1150&#xa0;°C. Compared to the control group without a molten salt medium, the reaction temperature and densification temperature were reduced by 50–150&#xa0;°C when using a molten salt medium. And the average particle size of the composite powder was significantly reduced by 41.9%. Research results indicate that the reaction temperature and aluminum dosage are the main factors affecting the phase composition of the composite powder. Incorporation of molten salt as the reaction medium not only reduced the reaction temperature but also efficiently suppressed particle aggregation. Additionally, the sintering process facilitates the stable formation of the final dual-phase structure and enhances powder compactness.</p> Graphical abstract <p></p>

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Preparation of dual-phase Al2O3/TiAl composite powder by thermite reduction in molten salt

  • 期刊论文

  • 发表日期：

    2026年3月26日

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  • Junde Zhao,
  • Hongyu Liu,
  • Jiaying Li

摘要

The manufacturing process of existing TiAl matrix composites relies heavily on expensive Ti powders. Additionally, traditional methods for preparing compound powders are subject to technical limitations, including excessively high reaction temperatures and particle agglomeration. To address these shortcomings and effectively convert low-cost TiO2 into compound powder, a new method for preparing Al2O3/TiAl composite powders using a ternary molten salt-assisted thermite reduction of TiO2 was proposed. And also we studied the regulatory mechanisms of process parameters, the molten salt medium, and the sintering process on the phase composition and microstructure of the powder. Dense γ-TiAl/α2-Ti3Al dual-phase Al2O3/TiAl composite powders were successfully synthesized under the conditions of an Al/TiO2 molar ratio of 1.628, a reaction temperature of 1000 °C for 2 h, and a sintering temperature of 1150 °C. Compared to the control group without a molten salt medium, the reaction temperature and densification temperature were reduced by 50–150 °C when using a molten salt medium. And the average particle size of the composite powder was significantly reduced by 41.9%. Research results indicate that the reaction temperature and aluminum dosage are the main factors affecting the phase composition of the composite powder. Incorporation of molten salt as the reaction medium not only reduced the reaction temperature but also efficiently suppressed particle aggregation. Additionally, the sintering process facilitates the stable formation of the final dual-phase structure and enhances powder compactness.

Graphical abstract