Metal-filled boron nitride nanotubes

We present the results on filling multi-walled BN nanotubes with 3d-transition metal nanorods. The nanorods made of either Fe-Ni Invar alloy (Fesimilar to60 at.%; Nisimilar to40 at.%) or pure Co were embedded into nanotubular channels via a two-stage process: first, C nanotubes containing Fe-Ni or Co nanoparticles at the tube-tips were synthesized by plasma-assisted chemical vapor deposition (CVD) on a Fe-Ni Invar or Co substrates, respectively, and, secondly, the material was heated to the melting points of the corresponding metals in a flow of B2O3 and N-2 gases and held for 0.5 h. During this second stage, simultaneous filling of nanotubes with the Fe-Ni or Co melt through capillarity and chemical modification of C tubular shells to form BN nanotubes occurred. The nanotubular shells and the fillings were analyzed by scanning electron microscopy (SEM), high-resolution analytical transmission electron microscopy (HRTEM), electron diffraction, electron energy-loss spectroscopy (EELS) and energy dispersion X-ray spectroscopy (EDX). The synthesized nanostructures are supposed to perform as "nanocables" having conducting metallic cores (Fe-Ni; Co) and insulating nanotubular shields (BN) with high environmental stability.