Vertical filler alignment of boron nitride/epoxy composite for thermal conductivity enhancement via external magnetic field

• Published in: International journal of thermal sciences Vol. 100; pp. 29 - 36
• Main Authors: Kim, Kiho, Kim, Jooheon
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 01.02.2016
• Subjects: Ceramic-polymer composite; Magnetic field; Thermal conductivity; Vertical alignment; Thermal conductivity; Vertical alignment; Ceramic-polymer composite; Magnetic field
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2015.09.013

Anisotropic boron nitride (BN) was vertically aligned along the direction of heat transport using a magnetic field. Iron oxide nanoparticles deposited onto the BN surface act as a magnetically responsive material allowing particle alignment. The amount of iron oxide deposited, and therefore the magnetic response, is easily controlled by modulating the precursors. The polarization of paramagnetic iron oxide in the magnetic field leads to the formation of vertical particle arrangements. The thermal conductivity of the synthesized vertically aligned composite increased from 1.765 W m−1 K−1 to 3.445 W m−1 K−1 with 30 vol% filler loading that is a 1.96-fold increase compared with a randomly oriented composite. The filler content affected both particle dispersion and arrangements, with homogeneously dispersed fillers aggregating due to induced dipole interactions into column-like structures with favorable thermal transport properties. •Iron oxide nanoparticles are formed on the boron nitride surface using functional groups.•Iron oxide content is controlled by amount of precursor.•Iron oxide coated BN particles are vertically aligned by external magnetic field.•Vertically aligned particles lead to enhancement of thermal conductivity.