Improvement of crystallization of borazine-derived boron nitride using small amounts of Fe or Ni nanoparticles

Homogenously dispersed Fe and Ni nanoparticles (NPs) are introduced into boron nitride (BN) by pyrolysis of cured borazine containing soluble ferrocene or nickelocene. The crystallization of the borazine-derived BN is significantly improved by using no more than 1 wt% NPs. X-ray diffraction (XRD) suggests that the improved BN obtained at 1200 °C exhibits a higher degree of crystallization close to that obtained at 1600 °C without additives. Transmission electron microscopy (TEM) indicates the formation of Fe or Ni NP-core multilayer BN spheres embedded in amorphous BN, and a corresponding core-shell model is suggested. The Ni NPs exhibit a higher crystallization than Fe NPs, possibly due to the higher solubility of boron in Ni NPs at elevated temperatures. In addition, we discuss the mechanisms by which Fe and Ni NPs improve the crystallization of BN from borazine.