Bulk Hexagonal Boron Nitride with a Quasi‐Isotropic Thermal Conductivity. (11th May 2018)

• Record Type: Journal Article
• Authors: Mateti, Srikanth; Yang, Keqin; Liu, Xuan; Huang, Shaoming; Wang, Jiangting; Li, Lu Hua; Hodgson, Peter; Zhou, Menhan; He, Jian; Chen, Ying
• Is Part Of: Advanced functional materials. Volume 28:Number 28(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-05-11
• Subjects: hexagonal boron nitride -- nanosheets -- quasi‐isotropic structure -- spark plasma sintering -- thermal conductivity; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201707556
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Hexagonal boron nitride (BN) is electrically insulating and has a high in‐plane thermal conductivity. However, it has a very low cross‐plane thermal conductivity which limits its application for efficient heat dissipation. Here, large BN pellets with a quasi‐isotropic thermal conductivity are produced from BN nanosheets using a spark plasma sintering (SPS) technique. The BN pellets have the same thermal conductivity from both perpendicular and parallel directions to the pellet surface. The high quasi‐isotropic thermal conductivity of the bulk BN is attributed to a quasi‐isotropic structure formed during the SPS process in which the charged BN nanosheets form large sheets in all directions under two opposite forces of SPS compression and electric field. The pellet sintered at 2300 °C has a very high cross‐section thermal conductivity of 280 W m −1 K −1 (parallel to the SPS pressing direction) and exhibits superior heat dissipation performance due to more efficient heat transfer in the vertical direction. Abstract : Quasi‐isotropic and highly thermally conductive boron nitride (BN) pellets are produced using spark plasma sintering of BN nanosheets. The BN nanosheet pellet prepared at 2300 °C under 50 MPa has the highest cross‐section thermal conductivity of 280 W m −1 K −1, and excellent heat dissipation performance, making it a promising heat spreader and heat sink for a wide range of applications.