Boron Nitride with Packets of Nanotubes for Microcomposite Ceramics

The possibility of creating microcomposite technical ceramics based on boron pyronitride (BPN) with nanotubes and packets of nanotubes providing a high microplasticity is considered. It is shown that the irradiation by nanosecond proton-ion beams with a high powder density promotes the growth of wurtzite-like BPN based on self-organizing mesoscopic (SOM) particles, SOM-blocks, and nanocrystalline particles. The sizes of SOM-particles and SOM-blocks of the initial and irradiated BPN are determined. The self-organization of nanotubes outside the zone of irradiation has a spiral cyclic nature and is caused by shear deformations of the layers composed of SOM-blocks. Tubes inclined to the surface with symmetry axes of the fifth order and packets of nanotubes of a disk shape are observed. The obtained micrographs are compared with model forms of manifestation of spiral cyclic structures.