Detonation nanodiamond (DND), also known as ultradispersed diamond (UDD), is

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, b ...

that originates from a

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

. When an oxygen-deficient explosive mixture of TNT/ RDX is detonated in a closed chamber, diamond particles with a diameter of c. 5 nm are formed at the front of the detonation wave in the span of several microseconds.

Properties

The diamond yield after detonation crucially depends on the synthesis condition and especially on the heat capacity of the cooling medium in the detonation chamber (water, air, CO₂, etc.). The higher the cooling capacity, the larger the diamond yield, which can reach 90%. After the synthesis, diamond is extracted from the soot using high-temperature high-pressure (

autoclave An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilizati ...

) boiling in acid for a long period (ca. 1–2 days). The boiling removes most of the metal contamination, originating from the chamber materials, and non-diamond carbon. Various measurements, including

X-ray diffraction X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

and

high-resolution transmission electron microscopy High-resolution transmission electron microscopy is an imaging mode of specialized transmission electron microscopes that allows for direct imaging of the atomic structure of samples. It is a powerful tool to study properties of materials on the a ...

, revealed that the size of the diamond grains in the soot is distributed around 5 nm. The grains are unstable with respect to aggregation and spontaneously form micrometre-sized clusters (see figure above). The adhesion is strong and contacts between a few nano-grains can hold a micrometre-sized cluster attached to a substrate. Nanosized diamond has extremely large relative surface area. As a result, its surface spontaneously attaches water and hydrocarbon molecules from the ambient atmosphere. However, clean nanodiamond surface can be obtained with appropriate handling. The detonation nanodiamond grains mostly have

diamond cubic The diamond cubic crystal structure is a repeating pattern of 8 atoms that certain materials may adopt as they solidify. While the first known example was diamond, other elements in group 14 also adopt this structure, including α-tin, the se ...

lattice and are structurally imperfect. The major defects are multiple twins, as suggested by high-resolution transmission electron microscopy. Despite the carbon source for the diamond synthesis—TNT/RDX explosive mixture—being rich in nitrogen, concentration of paramagnetic nitrogen inside diamond grains is below one part per million (ppm). Paramagnetic nitrogen (neutral nitrogen atoms substituting for carbon in the diamond lattice) is the major form of nitrogen in diamond, and thus the nitrogen content in DND is probably very low.

Alternative synthesis methods

Diamond nanocrystals can also be synthesized from a suspension of graphite in organic liquid at atmospheric pressure and room temperature using ultrasonic cavitation. The yield is approximately 10%. The cost of nanodiamonds produced by this method are estimated to be competitive with the

HPHT Lab-grown diamond (LGD; also called laboratory-grown, laboratory-created, man-made, artisan-created, artificial, synthetic, or cultured diamond) is diamond that is produced in a controlled technological process (in contrast to naturally formed ...

process. An alternative synthesis technique is irradiation of graphite by high-energy laser pulses. The structure and particle size of the obtained diamond is rather similar to that obtained in explosion. In particular, many particles exhibit multiple twinning. A research group from

Case Western Reserve University Case Western Reserve University (CWRU) is a private research university in Cleveland, Ohio. Case Western Reserve was established in 1967, when Western Reserve University, founded in 1826 and named for its location in the Connecticut Western Reser ...

produced nanodiamonds 2–5 nm in size at near-ambient conditions by a microplasma process. The nanodiamonds are formed directly from a gas and require no surface to grow on.

Applications

Commercial products based on nanodiamonds are available for the following applications: #

Lapping Lapping is a machining process in which two surfaces are rubbed together with an abrasive between them, by hand movement or using a machine. Lapping often follows other subtractive processes with more aggressive material removal as a first ste ...

and

polishing Polishing is the process of creating a smooth and shiny surface by rubbing it or by applying a chemical treatment, leaving a clean surface with a significant specular reflection (still limited by the index of refraction of the material accordin ...

(e.g. Sufipol); # Additives to engine oils (e.g. ADDO); #

Dry lubricants Dry lubricants or solid lubricants are materials that, despite being in the solid phase, are able to reduce friction between two surfaces sliding against each other without the need for a liquid oil medium. The two main dry lubricants are graphit ...

for

metal industry Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale ...

(Drawing of W-, Mo-, V-, Rh-wires); # Reinforcing fillers for

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adapta ...

and

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

, to modify the mechanical and thermal properties; # Thermal fillers for

and

, to create thermally conductive but electrically insulating materials for electronics) ; # Additives to

electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be ...

electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...

(e.g. DiamoSilb, DiamoChrom, Carbodeon uDiamond)

Use in medicine

Nanomaterials can shuttle chemotherapy drugs to cells without producing the negative effects of today's delivery agents. Clusters of the nanodiamonds surround the drugs ensuring that they remain separated from healthy cells, preventing unnecessary damage; upon reaching the intended targets, the drugs are released into the cancer cells. The leftover diamonds, hundreds of thousands of which could fit into the eye of a needle, do not induce inflammation in cells once they have done their job.

Ig Nobel 2012 Peace Prize

In 2012 the SKN Company was awarded the Ig Nobel Peace Prize for converting old Russian ammunition into nanodiamonds.The 2012 Ig Nobel Prize Winners
improbable.com

References

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External links

* http://pubs.acs.org/cgi-bin/sample.cgi/jpcbfk/asap/pdf/jp066387v.pdf * http://www.udayton.edu/News/Article/?contentId=2234 * http://research.ncl.ac.uk/nanoscale/research/nanodiamond.html Nanodiamond research at

Newcastle University Newcastle University (legally the University of Newcastle upon Tyne) is a UK public research university based in Newcastle upon Tyne, North East England. It has overseas campuses in Singapore and Malaysia. The university is a red brick unive ...

* http://www.ioffe.rssi.ru/nanodiamond/ Ioffe Physico-Technical Institute of the Russian Academy * http://www.cnn.com/2007/TECH/science/10/19/nanodiamonds.drugs/index.html * http://www.carbodeon.com * http://www.plasmachem.de/overview-powders.html#diamond Synthetic diamond Carbon nanoparticles Russian inventions Soviet inventions Diamond industry in the Soviet Union