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<p>This work investigates the growing behavior of reaction layers on TiO<sub>2</sub>-doped Al<sub>2</sub>O<sub>3</sub> ceramics in molten CMAS at 1250&#xa0;°C. Initial reactions rapidly form Ca<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> and CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub> phases. A thin-dense CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub> reaction layer (DRL) forms within 15&#xa0;min, evolving into a double-layered structure (outer CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>/ inner MgAl<sub>2</sub>O<sub>4</sub>) after 4&#xa0;h. The reaction layer thickening follows the parabolic law, with a rate that decreases significantly after 4&#xa0;h as the DRL plays a positive role in inhibiting the diffusion of Si<sup>4+</sup>, Al<sup>3+</sup>, and less effect on the, Mg<sup>2+</sup> and Ca<sup>2+</sup>. Crucially, the study elucidates the mechanism by which TiO<sub>2</sub> modulates the growing kinetics: TiO<sub>2</sub> enhances the chemical driving force for Ca<sup>2+</sup> infiltration through the DRL. This accelerated diffusion leads to the precipitation of a CaTiO<sub>3</sub> zone beneath the DRL, which alters the local compositional gradients and sustains the reaction layer growth. Kinetic models describing the layer thickness over time were established, and the underlying corrosion mechanisms were analyzed.</p>

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Influence of TiO2 addition on the growing behavior of dense reaction layer in Al2O3 ceramics during CMAS corrosion at 1250 °C

  • 期刊论文

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  • 发表日期：

    2026年6月15日

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  • Shuang Huang,
  • Zhiyun Yu,
  • Ronghui Mao,
  • Du Huang,
  • Xuanchen Wei,
  • Tianquan Liang

摘要

This work investigates the growing behavior of reaction layers on TiO2-doped Al2O3 ceramics in molten CMAS at 1250 °C. Initial reactions rapidly form Ca2MgSi2O7 and CaAl2Si2O8 phases. A thin-dense CaAl2Si2O8 reaction layer (DRL) forms within 15 min, evolving into a double-layered structure (outer CaAl2Si2O8/ inner MgAl2O4) after 4 h. The reaction layer thickening follows the parabolic law, with a rate that decreases significantly after 4 h as the DRL plays a positive role in inhibiting the diffusion of Si4+, Al3+, and less effect on the, Mg2+ and Ca2+. Crucially, the study elucidates the mechanism by which TiO2 modulates the growing kinetics: TiO2 enhances the chemical driving force for Ca2+ infiltration through the DRL. This accelerated diffusion leads to the precipitation of a CaTiO3 zone beneath the DRL, which alters the local compositional gradients and sustains the reaction layer growth. Kinetic models describing the layer thickness over time were established, and the underlying corrosion mechanisms were analyzed.