Investigation of the Role of Calcium Borate in the Growth of Hexagonal Boron Nitride Particles



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Submitted Jun 2, 2022
Published Jun 30, 2022
10.24018/ejeng.2022.7.3.2834

Abstract viewed = 363 times

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Hexagonal boron nitride (h-BN) powder is a promising thermally conductive filler in resins and controlling its particle size is important. To obtain h-BN powder with a large particle size as well as high purity and crystallinity, high-temperature heat treatment over 1800 oC in N2 gas atmosphere is effective. Carbothermal reduction nitridation (CRN) involves carbothermic reduction of boric oxide in N2 gas atmosphere. In CRN using a CaO promoter, h-BN particles with large sizes can be produced through a simple heat-treatment process. During CRN, CaO forms calcium borate (CaO-B2O3), which prevents the vaporization of B2O3 and promotes h-BN particle growth at high temperatures. Up to now, the effect of CaO-B2O3 on the growth of h-BN particles during CRN is unclear. In this study, the role of CaO-B2O3 in the growth of h-BN particles during CRN was clarified via experimentation using various approaches. The results led to the ideal reaction process of CRN using a CaO promoter to produce large-particle-size h-BN powder.

Keywords: Boron nitride Heat-treatment Particle growth

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