[en] A facile method was proposed to use Ni/Al₂O₃ as a catalyst to produce metallic nickel filled carbon nanotubes. Multi-walled carbon nanotubes filled with long continuous nickel nanowire length were synthesized through chemical vapor deposition at low temperature (600 deg. C). Furthermore, the multi-walled carbon nanotubes were well-graphitized nanotubes. The analysis of scanning electron microscopy, transmission electron microscopy, selected area electron diffraction and X-ray diffraction revealed that the metallic nickel nanowires encapsulated inside carbon nanotubes existed as a single crystalline with fcc structure