A feasibility study of preparing carbon nanotubes by using a metal dusting process

Iron and nickel, model alloys of Ni-Cu and Fe-Cr, and commercial heat resisting alloys were exposed at 650-680oC to flowing CO-H2-H2O gases which were supersaturated with respect to carbon. All ferritic materials, including chromia and alumina formers, developed a coke deposit of carbon nanotubes, the growth of which was catalysed by nanoparticles of Fe3C. Austenitic materials formed graphite filaments and clusters in association with nanoparticles of austenite. Graphite cluster formation was suppressed by alloying copper with nickel. The sensitivity of coking kinetics to alloy copper content was consistent with a mechanism involving graphite nucleation within the subsurface metal. Chromia forming alloys resisted dusting until damage to the scale could no longer be repaired by Cr2O3 regrowth, and carbon gained access to chromium – depleted metal.

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A feasibility study of scaling-up the electrolytic production of carbon nanotubes in molten salts

Electrochimica Acta ◽

10.1016/s0013-4686(02)00595-9 ◽

2002 ◽

Vol 48 (1) ◽

pp. 91-102 ◽

Cited By ~ 33

Author(s):

Aleksandar T Dimitrov ◽

George Z Chen ◽

Ian A Kinloch ◽

Derek J Fray

Keyword(s):

Carbon Nanotubes ◽

Feasibility Study ◽

Molten Salts ◽

Scaling Up ◽

Electrolytic Production

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Structural phenomena in the growth of carbon nanotubes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149581 ◽

1993 ◽

Vol 51 ◽

pp. 750-751

Author(s):

Jun Jiao

Keyword(s):

Carbon Nanotubes ◽

Growth Mechanism ◽

Carbonaceous Material ◽

Cluster Growth ◽

Structural Elements ◽

Rich Variety ◽

Different Shapes ◽

Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

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