Synthesis and growth mechanism of single crystal β‐Si 3 N 4 particles with a quasi‐spherical morphology

Single‐crystal β‐Si 3 N 4 particles with a quasi‐spherical morphology were synthesized via an efficient carbothermal reduction‐nitridation (CRN) strategy. The β‐Si 3 N 4 particles synthesized under an N 2 pressure of 0.3 MPa, at 1450°C and with 10 mol% unique CaF 2 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‐Si 3 N 4 products. Selected‐area electron‐diffraction pattern and high‐resolution image indicated single crystalline structure of the typical β‐Si 3 N 4 particles without an obvious amorphous oxidation layer on the surface. The growth mechanism of the quasi‐spherical β‐Si 3 N 4 particles was proposed based on the transmission electron microscopy and energy dispersive X‐ray spectroscopy characterization, which was helpful for controllable synthesis of β‐Si 3 N 4 particles by CRN method. Owing to the quasi‐spherical morphology, good dispersity, high purity, and single‐crystal structure, the submicro‐sized β‐Si 3 N 4 particles were promising fillers for preparing resin‐based composites with high thermal conductivity.