Synthesis of vapor - Grown carbon fibers using nanocrystalline Fe₉₁Zr₇B₂ alloy as a catalyst

The synthesis of vapor-grown carbon fibers (VGCFs) using the nanocrystalline Fe₉₁Zr₇B₂ alloy as a novel catalyst, and the growth process of these VGCFs, have been investigated. We selected the nanocrystalline Fe₉₁Zr₇B₂ alloy as a novel catalyst for VGCF synthesis. The nanocrystalline Fe₉₁Zr₇B₂ alloy with fine bcc-Fe grains (∼20nm) was prepared by a melt-spinning technique followed by annealing at 873 K for 5 min. VGCFs with a width ranging from 50 to 300nm and a maximum length of about 6μm were successfully prepared, by using a nanocrystalline Fe₉₁Zr₇B₂ alloy annealed at 873 K under a 80%CO-20%H₂ mixture. From HREM observation, it was found that the catalyst particle was made of fine bcc-Fe grains, and the VGCF consisted of graphite platelets with the spacing 0.396 nm, that were stacked in a direction parallel to the base of the catalyst particle and perpendicular to the fiber axis. The growth process of the VGCF using the nanocrystalline Fe₉₁Zr₇B₂ alloy can be described by two major stages, i.e., "the separation of catalyst particles" and "fiber growth."