Fabrication and Properties of Machinable AlN-BN Ceramic Nanocomposites

Abstract:

The AlN/h-BN nanocomposite powders were synthesized through the reaction of AlN powder, boric acid (H3BO3) and urea (CO(NH2)2) in a nitrogen atmosphere, and the machinable AlN/BN ceramic nanocomposite s were fabricated by hot-pressing in N2 atmosphere. The existing and distribution of h-BN phase are revealed by X-ray diffraction (XRD), TEM and SEM. For the existing of weak interface between h-BN and AlN grains, the machinability of AlN/BN composites is improved obviously. For the finer microstructures, the mechanical properties and the machinability of the composites with micrometer sized AlN coated with nano-sized BN are better than the AlN/h-BN composite of mechanical mixing type.