Insulating 'nanocables': Invar Fe-Ni alloy nanorods inside BN nanotubes

Here we present the results on synthesis, structural and chemical analysis of insulating boron nitride (BN) nanotubes (NTs) which have been filled wit h conducting Invar Fe-Ni alloy (similar to 60 at.% Fe; similar to 40 at.% N i) nanorods. The result was accomplished by a two-step process: (i) carbon (C) NTs containing Invar alloy nanoparticles placed at the tube tips were s ynthesized by plasma-assisted chemical vapor deposition (CVD) on an Invar F e-Ni alloy substrate; and (ii) the material was heated to the melting point of the alloy (1723 K) in a flow of B2O3 and N-2 gases and held for 30 min. During this second stage, simultaneous filling of NTs with the Fe-Ni melt through capillarity and chemical modification of C tubular shells to form B N tubules occurred. (C) 2001 Published by Elsevier Science B.V.