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<p>This study presents a systematic examination of particle size effects on the oxidation mechanisms of silicon carbide (SiC) powders. Using a combination of X-ray diffraction, Fourier Transform Infrared spectroscopy, and Raman spectroscopy techniques, we characterized distinct oxidation pathways for different particle sizes. The experimental results demonstrate significant differences in oxidation behavior between micron-scale (M-SiC) and submicron-scale (SM-SiC) particles. M-SiC showed initial oxidation commencing at 900&#xa0;°C, with crystalline cristobalite SiO<sub>2</sub> formation occurring at 1185&#xa0;°C. In comparison, SM-SiC exhibited substantially higher reactivity, with oxidation initiation observed at a much lower temperature of 600&#xa0;°C and amorphous SiO<sub>2</sub> generation at 1100&#xa0;°C. Transmission electron microscopy investigations revealed striking contrasts in oxide layer development. After exposure to 1200&#xa0;°C, M-SiC formed a relatively thin (~ 20&#xa0;nm) oxide layer, while SM-SiC developed a significantly thicker oxide layer exceeding 100&#xa0;nm under identical conditions. Isoconversional kinetic analysis revealed three distinct oxidation stages for both powder types. Compared to M-SiC, SM-SiC exhibited significantly lower apparent activation energies in the corresponding stages. Mechanistic analysis uncovered fundamental distinctions: M-SiC oxidation followed a random nucleation and growth model throughout all stages, while SM-SiC progressed from nucleation-controlled kinetics (Stage 1) to three-dimensional diffusion-dominated mechanisms in subsequent stages. These results offer valuable insights into the particle-size-dependent oxidation mechanisms of SiC powders.</p>

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New insight into non-isothermal kinetics of oxidation of SiC powders: the effect of particle size

  • 期刊论文

  • 发表日期：

    2025年8月8日

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  • Wentao Liu,
  • Hanting Zhang,
  • Boning Zhang,
  • Suping Huang,
  • Qi Xiao

摘要

This study presents a systematic examination of particle size effects on the oxidation mechanisms of silicon carbide (SiC) powders. Using a combination of X-ray diffraction, Fourier Transform Infrared spectroscopy, and Raman spectroscopy techniques, we characterized distinct oxidation pathways for different particle sizes. The experimental results demonstrate significant differences in oxidation behavior between micron-scale (M-SiC) and submicron-scale (SM-SiC) particles. M-SiC showed initial oxidation commencing at 900 °C, with crystalline cristobalite SiO2 formation occurring at 1185 °C. In comparison, SM-SiC exhibited substantially higher reactivity, with oxidation initiation observed at a much lower temperature of 600 °C and amorphous SiO2 generation at 1100 °C. Transmission electron microscopy investigations revealed striking contrasts in oxide layer development. After exposure to 1200 °C, M-SiC formed a relatively thin (~ 20 nm) oxide layer, while SM-SiC developed a significantly thicker oxide layer exceeding 100 nm under identical conditions. Isoconversional kinetic analysis revealed three distinct oxidation stages for both powder types. Compared to M-SiC, SM-SiC exhibited significantly lower apparent activation energies in the corresponding stages. Mechanistic analysis uncovered fundamental distinctions: M-SiC oxidation followed a random nucleation and growth model throughout all stages, while SM-SiC progressed from nucleation-controlled kinetics (Stage 1) to three-dimensional diffusion-dominated mechanisms in subsequent stages. These results offer valuable insights into the particle-size-dependent oxidation mechanisms of SiC powders.