Conversion of Nickel Coated Carbon Nanotubes to Diamond under High Pressure and High Temperature

Abstract

Nickel coated carbon nanotubes have been converted to diamonds with high conversion ratio at 8 GPa and 1600°C. Nickel coated on the surface of each and every carbon nanotube might act as catalyst and play the key role for high conversion ratio of carbon nanotubes to diamond. Pure carbon nanotubes can only be converted to high oriented graphite under same high pressure and high temperature condition.

Spark plasma sintering assisted diamond formation from carbon nanotubes at very low pressure

“…The relatively low pressure of 80 MPa applied in the present SPS-assisted diamond generation is rather interesting when compared with other processes employed to convert CNTs to diamond, such as laser irradiation [17], shock wave synthesis [18], chemical vapour deposition by nanotube coating [19], high-pressure and/or high-temperature (HPHT) treatment [20,21], and hydrogen plasma post-treatment [14]. Generally, pressures greater than several GPa and high temperatures are needed.…”

Methods for preparation of carbon nanotubes

“…Ordered structures from NT prepared by the pyrolytic method are best suited for template synthesis, i.e. application of metals, for example, Ni or Co on their surface, 142,230,231 for deposition of oxides, 63 carbides 232 ± 235 or gallium nitride, 236 for the preparation of catalysts, sorbents, membranes for electrochemical cells, 152 field emitters and artificial muscles (actuators).…”

Novel nanoscale architectures: coated nanotubes and other nanowires

“…While this article focuses on nano-architecture, there are a number of other uses for nanocomposites, as presented within the references. Amongst the more exciting research is that into the Ni coating of CNTs which subsequently acts as a catalyst in the conversion of the nanotube to diamond at 8 GPa and 1600 • C (Han et al . 1998), whereas uncoated CNTs were converted to highly ordered graphite under similar conditions.…”