Affiliation:
1. Key Laboratory of Cryogenic Science and Technology Technical Institute of Physics and Chemistry Chinese Academy of Science Beijing China
2. Tianjin Key Laboratory of Functional Crystal Materials Institute of Functional Crystal College of Material Science and Engineering Tianjin University of Technology Tianjin China
3. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing China
Abstract
AbstractHigh thermally conductive β‐Si3N4 is a new type of filler for thermally conductive materials. Tailoring its aspect ratio is crucial to optimize the preparation process and performance of polymer‐based thermal conductive materials. In this work, β‐Si3N4/BN thermally conductive hybrid fillers were prepared by combustion synthesis in a nitrogen atmosphere using low‐cost Si, B2O3 powders as raw materials, and the aspect ratio of β‐Si3N4 crystals were regulated according to the inhibiting growth strategy of second phase BN generated by in situ reaction. With the increase of B2O3, the content of BN increased slightly, while that of β‐Si3N4 decreased slightly. The aspect ratio of β‐Si3N4 decreased from 6.3 ± 1.9 to 1.9 ± 0.6, which might be ascribed to the inhibiting effect of BN sheets on the axial growth of rod‐like β‐Si3N4. Low‐aspect‐ratio β‐Si3N4/BN/epoxy composite exhibited high thermal conductivity of 1.04 W·m‐1·K‐1at the solid content of 50 wt%, which was 372.7% and 30.0% higher than that of neat epoxy and 40 wt% high‐aspect‐ratio β‐Si3N4/epoxy composite, respectively. In addition, β‐Si3N4/BN/epoxy composite also had good mechanical properties.
Funder
National Natural Science Foundation of China