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过程工程学报 ›› 2025, Vol. 25 ›› Issue (10): 1064-1074.DOI: 10.12034/j.issn.1009-606X.225050

• 研究论文 • 上一篇    下一篇

熔盐热解法制备α相氮化硅粉体

杨帆， 韩召*， 刘鹏飞， 李杰   

  1. 安徽工业大学冶金工程学院，安徽 马鞍山 243000
  • 收稿日期:2025-02-18 修回日期:2025-04-03 出版日期:2025-10-28 发布日期:2025-10-28
  • 通讯作者: 韩召 hanzhao3208@163.com
  • 基金资助:
    国家自然科学基金项目

Preparation of α phase silicon nitride powder by molten salt pyrolysis

Fan YANG,  Zhao HAN*,  Pengfei LIU,  Jie LI   

  1. School of Metallurgical Engineering, Anhui University of Technology, Ma'anshan, Anhui 243000, China
  • Received:2025-02-18 Revised:2025-04-03 Online:2025-10-28 Published:2025-10-28

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摘要： 随着氮化硅(Si3N4)陶瓷在航空航天、电子器件和高温结构材料等应用领域的不断扩展，对高质量Si3N4粉体的需求日益增加。然而，传统硅亚胺热解法普遍存在结晶温度较高与晶须易形成的问题，严重影响Si3N4粉体质量与应用性能。本研究的创新点在于引入熔盐环境，通过降低硅亚胺[Si(NH)2]的结晶与相变温度，实现了对Si3N4粉体粒径的控制，并避免了不规则晶须的生成。研究以Si(NH)2为原料、氯化钠(NaCl)为熔盐介质，采用熔盐热解法制备了形貌规则的α-Si3N4粉体，并探究了热解温度和硅盐比对粉体物相组成、粒径分布及微观形貌的影响。结果表明，NaCl熔盐可显著降低Si(NH)2结晶与相变温度，在1400℃保温2 h的条件下，Si(NH)2可完全转化为结晶度高、形貌规则的Si3N4粉体，其中α-Si3N4含量达75.52wt%，平均粒径为905.40 nm。此外，随NaCl熔盐含量增加，粉体中α-Si3N4含量呈先降低后增加的变化趋势，但粉体粒径逐渐减小。该方法有效抑制Si(NH)2热解过程中晶须的形成，降低α-Si3N4粉体的结晶温度。机理分析显示，在熔盐提供的液相环境中，Si(NH)2通过溶解-析出机制促进α-Si3N4颗粒生长。此方法为制备高质量、形貌规则的Si3N4粉体提供了新思路，具有广泛的应用潜力。

关键词: 氮化硅, 熔盐, 粉体, 硅亚胺

Abstract: With the continuous expansion of silicon nitride (Si3N4) ceramics in application fields such as aerospace, electronic devices, and high-temperature structural materials, the demand for high-quality Si3N4 powder has been increasingly growing. However, the traditional pyrolysis of silicon imine [Si(NH)2] usually faces the problems of high crystallization temperature and whisker formation, which affects the quality and application performance of the final Si3N4 powder. The innovation of this study is to use molten salt environment to reduce the crystallization and phase transition temperature of Si(NH)2, control particle size and inhibit the formation of irregular whiskers. In this study, α-Si3N4 powder with regular morphology is prepared by molten salt pyrolysis method, using Si(NH)2 as raw material and sodium chloride (NaCl) as reactive medium. Meanwhile, the effects of pyrolysis temperature and the ratio of silicon to salt on the phase composition, particle size distribution, and microstructure of the prepared powder are investigated. The results indicate that NaCl molten salt can significantly lower the crystallization and phase transition temperatures of Si(NH)2. Under the condition of holding at 1400℃ for 2 h, Si(NH)2 is completely converted into Si3N4 powder with high crystallinity and regular morphology. The content of α-Si3N4 is 75.52wt%, and the average particle size is 905.40 nm. In addition, with the increase of NaCl content, the α-Si3N4 content in the powder first decreases and then increases, whereas the powder particle size gradually reduces. This method effectively inhibits the formation of whiskers during the pyrolysis of Si(NH)2 and lowers the crystallization temperature of α-Si3N4 powder. Mechanistic analysis reveals that in the liquid-phase environment provided by the molten salt, Si(NH)2 promotes the growth of α-Si3N4 particles through a dissolution-precipitation mechanism. Overall, This method provides a new strategy for preparing high-quality Si3N4 powder with regular morphology and exhibits broad application potential.

Key words: silicon nitride, molten salt, powder, silicon imine