Synthesis and growth mechanism of single crystal β-Si3N4 particles with a quasi-spherical morphology

• Main Authors: Sun, Si-Yuan, Ge, Yi-Yao, Wang, Qi, Tian, Zhao-Bo, Zhang, Jie, Cui, Wei, Liu, Guang-Hua, Chen, Ke-Xin
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Materials; Additives; Particles
• Online Access: https://hdl.handle.net/10356/137693
• Institution: Nanyang Technological University

Single‐crystal β‐Si3N4 particles with a quasi‐spherical morphology were synthesized via an efficient carbothermal reduction‐nitridation (CRN) strategy. The β‐Si3N4 particles synthesized under an N2 pressure of 0.3 MPa, at 1450°C and with 10 mol% unique CaF2 additives showed good dispersity and an average size of about 650 nm. X‐ray photoelectron spectroscopy analysis revealed that there was no SiC or Si–C–N compounds in the β‐Si3N4 products. Selected‐area electron‐diffraction pattern and high‐resolution image indicated single crystalline structure of the typical β‐Si3N4 particles without an obvious amorphous oxidation layer on the surface. The growth mechanism of the quasi‐spherical β‐Si3N4 particles was proposed based on the transmission electron microscopy and energy dispersive X‐ray spectroscopy characterization, which was helpful for controllable synthesis of β‐Si3N4 particles by CRN method. Owing to the quasi‐spherical morphology, good dispersity, high purity, and single‐crystal structure, the submicro‐sized β‐Si3N4 particles were promising fillers for preparing resin‐based composites with high thermal conductivity.