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Synthesis of near‐spherical α‐Si 3 N 4 powder via carbon‐assisted crystallization of amorphous Si 3 N 4 powder

Year: 2025
Type: article
Abstract: This study presents a scalable method for fabricating near‐spherical silicon nitride (Si 3 N 4 ) particles with a high α phase content. Amorphous Si 3 N 4 powder was synthesized using the diimide synthesis method, mixed with graphite powder as a carbon source, and calcined at 1550°C to produce α‐Si 3 N 4 powder. The effects of varying carbon contents on the phase composition and microstructure of the resulting products were investigated. In the presence of carbon, the Si 3 N 4 particles exhibit a near‐spherical morphology, with a reduction in the fraction of whisker‐like structures. The products show a complex, nonuniform structure with a broad particle size distribution and varying structural characteristics when excessive powder is added. Graphite powder not only provides nucleation sites but also plays a critical role in the phase transition from amorphous Si 3 N 4 to the α phase. The nucleation and growth of α‐Si 3 N 4 are facilitated by the presence of SiO(g), which is reduced through interactions with C(s) or CO(g). It indicates that carbon accelerates the Si 3 N 4 phase transition through the vapor‐solid mechanism, which is the key to inhibiting the whisker growth and controlling the particle size of α‐Si 3 N 4 powder.
DOI: 10.1111/ijac.70014
Language: English
Open Access status: bronze
OpenAlex ID: W4411836811
FWCI: 0.32
Cites: 40
Cited by: 1
Related to: 10