Precursor synthesis and high-temperature refinement of hexagonal boron nitride particles

C₃H₆N₆·2H₃BO₃ was synthesized by coprecipitation method using melamine and boric acid as raw materials, and used as precursor to prepare h-BN particles by sintering in ammonia gas atmosphere. The precursor and product were respectively characterized by IR, XRD, TG and SEM analyses. The results indicated that h-BN with high purity and good crystalline can be obtained via calcining the precursor at 1200℃ for 4 h. After high-temperature refinement, the resultant h-BN particles exhibit high crystallinity and compactness, with a particle size of larger than 20 μm and a purity of 98.5%.