By Josh Perry, Editor
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Boron-nitride has suddenly become a popular material for thermal engineers to study, as researchers at the Deakin University Institute for Frontier Materials (Victoria, Australia) announced the creation of the first bulk boron nitride with high thermal conductivity.

Researchers at Deakin University have developed a new method for producing bulk boron-nitride. (Wikimedia Commons)

This announcement follows on the heels of similar research into the material, including UCLA researchers announcing a new thermal benchmark for boron-nitride crystals, researchers from UT-Dallas and other schools creating boron-nitride with high thermal conductivity, and researchers from the University of Houston announcing the first bulk crystals of boron-nitride.

According to the article from Deakin, the goal of the new material is to replace silicon and help advance the production of smaller, faster, and more powerful electronics by removing the issue of overheating. Hexagonal boron-nitride also has the added benefit of being an electrical insulator.

One concern that was noted by Deakin researchers is that boron-nitride has uneven thermal conductivity different directions, which could create hotspots in boron-nitride films.

To create the bulk boron-nitride, Deakin researchers worked with scientists from China and the U.S. to produce pellets of the material from boron-nitride nanosheets through spark plasma sintering (SPS).

The research was recently published in Advanced Functional Materials. The abstract stated:

“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.”