Abstract The synthesis of 15R-SiAlON in FexSiy-Si3N4-Al2O3 composites was carried out at 1800 °C in flowing nitrogen. The role of the vapour phases from ferrosilicon nitride (FexSiy-Si3N4) and Al2O3 was studied by phase evolution, microstructure, and thermodynamic analyses. The results show that the formation of 15R-SiAlON is highly related to SiO(g), Si(g), Al2O(g) and Al(g) from FexSiy-Si3N4-Al2O3 composites. At 1800 °C in flowing nitrogen, SiO(g) and Si(g) are generated from ferrosilicon nitride. Al2O(g) and Al(g) are released from Al2O3, and their pressures depend on that of oxygen. The increase of ferrosilicon nitride promotes the generation of vapour phases. The diffusion of Al2O(g) and Al(g) into Si3N4, and of SiO(g) and Si(g) into Al2O3 particles enable the growth of 15R-SiAlON flakes based on both the Si3N4 and Al2O3 substrates by solid-gas reaction. In the presence of the Fe-Si liquid, 15R-SiAlON whiskers with Fe-Si sphere on the top are generated by the liquid-solid-gas mechanism. The reactions between Al2O(g)/Al(g) and SiO(g)/Si(g) in nitrogen generate large amounts of 15R-SiAlON whiskers by the gas-gas mechanism.

中文翻译：

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1800 °C 时气相在 FexSiy-Si3N4-Al2O3 复合材料中 15R-SiAlON 形成机制中的作用

摘要 FexSiy-Si3N4-Al2O3 复合材料中 15R-SiAlON 的合成是在 1800 °C 下在流动氮气中进行的。通过相演化、微观结构和热力学分析研究了氮化硅铁 (FexSiy-Si3N4) 和 Al2O3 气相的作用。结果表明，15R-SiAlON 的形成与 FexSiy-Si3N4-Al2O3 复合材料中的 SiO(g)、Si(g)、Al2O(g) 和 Al(g) 高度相关。在 1800 °C 的流动氮气中，SiO(g) 和 Si(g) 由氮化硅铁生成。Al2O(g) 和 Al(g) 从 Al2O3 中释放出来，它们的压力取决于氧气的压力。氮化硅铁的增加促进了气相的产生。Al2O(g)和Al(g)扩散到Si3N4中，以及将 SiO(g) 和 Si(g) 转化为 Al2O3 颗粒能够通过固气反应基于 Si3N4 和 Al2O3 基材生长 15R-SiAlON 薄片。在 Fe-Si 液体的存在下，15R-SiAlON 晶须在顶部带有 Fe-Si 球体，通过液-固-气机制产生。Al2O(g)/Al(g) 和 SiO(g)/Si(g) 在氮气中的反应通过气-气机制产生大量 15R-SiAlON 晶须。