Aggregated diamond nanorod

Aggregated diamond nanorods, or ADNRs, are a nanocrystalline form of diamond, also known as nanodiamond or hyperdiamond.

Popigai nanodiamonds
Natural nanodiamond aggregates from the Popigai crater, Siberia, Russia.[1]
Natural nanodiamond TEM
Internal structure of the Popigai nanodiamonds.[1]
Synthetic nanodiamond TEM
Internal structure of synthetic nanodiamonds.[1]

Discovery

Nanodiamond or hyperdiamond was convincingly demonstrated to be produced by compression of graphite in 2003 and in the same work found to be much harder than bulk diamond.[2] Later it was also produced by compression of fullerene and confirmed to be the hardest and least compressible known material, with an isothermal bulk modulus of 491 gigapascals (GPa), while a conventional diamond has a modulus of 442–446 GPa; these results were inferred from X-ray diffraction data, which also indicated that ADNRs are 0.3% denser than regular diamond.[3] The same group later described ADNRs as "having a hardness and Young's modulus comparable to that of natural diamond, but with 'superior wear resistance'".[4]

Hardness

A <111> surface (normal to the largest diagonal of a cube) of pure diamond has a hardness value of 167±6 GPa when scratched with a nanodiamond tip, while the nanodiamond sample itself has a value of 310 GPa when tested with a nanodiamond tip.[5] However, the test only works properly with a tip made of harder material than the sample being tested. This means that the true value for nanodiamond is likely somewhat lower than 310 GPa.

Synthesis

ADNRs (hyper diamonds / nano diamonds) are produced by compressing fullerite powder—a solid form of allotropic carbon fullerene—by any of two somewhat similar methods. One uses a diamond anvil cell and applied pressure ~37 GPa without heating the cell.[6] In another method, fullerite is compressed to lower pressures (2–20 GPa) and then heated to a temperature in the range of 300 to 2,500 K (27 to 2,227 °C).[7][8][9][10] Extreme hardness of what now appears likely to have been nanodiamonds was reported by researchers in the 1990s.[5][6] The material is a series of interconnected diamond nanorods, with diameters of between 5 and 20 nanometres and lengths of around 1 micrometre each.

Nanodiamond aggregates ca. 1 mm in size also form in nature, from graphite upon meteoritic impact, such as that of the Popigai crater in Siberia, Russia.[11]

See also

References

  1. ^ a b c Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D.; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P.; Pokhilenko, Nikolai P. (2015). "Natural occurrence of pure nano-polycrystalline diamond from impact crater". Scientific Reports. 5: 14702. Bibcode:2015NatSR...514702O. doi:10.1038/srep14702. PMC 4589680. PMID 26424384.
  2. ^ Irifune, Tetsuo; Kurio, Ayako; Sakamoto, Shizue; Inoue, Toru; Sumiya, Hitoshi (2003). "Materials: Ultrahard polycrystalline diamond from graphite". Nature. 421 (6923): 599–600. Bibcode:2003Natur.421..599I. doi:10.1038/421599b. PMID 12571587.
  3. ^ Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Crichton, Wilson; Langenhorst, Falko; Richter, Asta (2005). "Aggregated diamond nanorods, the densest and least compressible form of carbon". Applied Physics Letters. 87 (8): 083106. Bibcode:2005ApPhL..87h3106D. doi:10.1063/1.2034101.
  4. ^ Dubrovinskaia, Natalia; Dub, Sergey; Dubrovinsky, Leonid (2006). "Superior Wear Resistance of Aggregated Diamond Nanorods". Nano Letters. 6 (4): 824. Bibcode:2006NanoL...6..824D. doi:10.1021/nl0602084. PMID 16608291.
  5. ^ a b Blank, V (1998). "Ultrahard and superhard phases of fullerite C60: Comparison with diamond on hardness and wear" (PDF). Diamond and Related Materials. 7 (2–5): 427. Bibcode:1998DRM.....7..427B. doi:10.1016/S0925-9635(97)00232-X. Archived from the original (PDF) on 2011-07-21.
  6. ^ a b Blank, V; Popov, M; Buga, S; Davydov, V; Denisov, V; Ivlev, A; Marvin, B; Agafonov, V; et al. (1994). "Is C60 fullerite harder than diamond?". Physics Letters A. 188 (3): 281. Bibcode:1994PhLA..188..281B. doi:10.1016/0375-9601(94)90451-0.
  7. ^ Kozlov, M (1995). "Superhard form of carbon obtained from C60 at moderate pressure". Synthetic Metals. 70: 1411. doi:10.1016/0379-6779(94)02900-J.
  8. ^ Blank, V (1995). "Ultrahard and superhard carbon phases produced from C60 by heating at high pressure: structural and Raman studies". Physics Letters A. 205 (2–3): 208. Bibcode:1995PhLA..205..208B. doi:10.1016/0375-9601(95)00564-J.
  9. ^ Szwarc, H; Davydov, V; Plotianskaya, S; Kashevarova, L; Agafonov, V; Ceolin, R (1996). "Chemical modifications of C under the influence of pressure and temperature: from cubic C to diamond". Synthetic Metals. 77: 265. doi:10.1016/0379-6779(96)80100-7.
  10. ^ Blank, V (1996). "Phase transformations in solid C60 at high-pressure-high-temperature treatment and the structure of 3D polymerized fullerites". Physics Letters A. 220: 149. Bibcode:1996PhLA..220..149B. doi:10.1016/0375-9601(96)00483-5.
  11. ^ Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D.; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P.; Pokhilenko, Nikolai P. (2015). "Natural occurrence of pure nano-polycrystalline diamond from impact crater". Scientific Reports. 5: 14702. Bibcode:2015NatSR...514702O. doi:10.1038/srep14702. PMC 4589680. PMID 26424384.

External links

Buckminsterfullerene

Buckminsterfullerene is a type of fullerene with the formula C60. It has a cage-like fused-ring structure (truncated icosahedron) that resembles a soccer ball (football), made of twenty hexagons and twelve pentagons, with a carbon atom at each vertex of each polygon and a bond along each polygon edge.

Index of physics articles (A)

The index of physics articles is split into multiple pages due to its size.

To navigate by individual letter use the table of contents below.

Lonsdaleite

Lonsdaleite (named in honour of Kathleen Lonsdale), also called hexagonal diamond in reference to the crystal structure, is an allotrope of carbon with a hexagonal lattice. In nature, it forms when meteorites containing graphite strike the Earth. The great heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite was first identified in 1967 from the Canyon Diablo meteorite, where it occurs as microscopic crystals associated with diamond.Hexagonal diamond has also been synthesized in the laboratory (1966 or earlier; published in 1967) by compressing and heating graphite either in a static press or using explosives. It has also been produced by chemical vapor deposition, and also by the thermal decomposition of a polymer, poly(hydridocarbyne), at atmospheric pressure, under argon atmosphere, at 1,000 °C (1,832 °F).It is translucent, brownish-yellow, and has an index of refraction of 2.40 to 2.41 and a specific gravity of 3.2 to 3.3. Its hardness is theoretically superior to that of cubic diamond (up to 58% more), according to computational simulations, but natural specimens exhibited somewhat lower hardness through a large range of values (from 7 to 8 on Mohs hardness scale). The cause is speculated as being due to the samples having been riddled with lattice defects and impurities.The property of lonsdaleite as a discrete material has been questioned, since specimens under crystallographic inspection showed not a bulk hexagonal lattice, but instead cubic diamond dominated by structural defects that include hexagonal sequences. A quantitative analysis of the X-ray diffraction data of lonsdaleite has shown that about equal amounts of hexagonal and cubic stacking sequences are present. Consequently, it has been suggested that "stacking disordered diamond" is the most accurate structural description of lonsdaleite. On the other hand, recent shock experiments with in situ X-ray diffraction show strong evidence for creation of relatively pure lonsdaleite in dynamic high-pressure environments such as meteorite impacts.

Nanodiamond

Nanodiamonds or diamond nanoparticles (medical use) are diamonds with a size below 1 micrometre. They can be produced by impact events such as an explosion or meteoritic impacts. Because of their inexpensive, large-scale synthesis, potential for surface functionalization, and high biocompatibility, nanodiamonds are widely investigated as a potential material in biological and electronic applications and quantum engineering.

Nanorod

In nanotechnology, nanorods are one morphology of nanoscale objects. Each of their dimensions range from 1–100 nm. They may be synthesized from metals or semiconducting materials. Standard aspect ratios (length divided by width) are 3-5. Nanorods are produced by direct chemical synthesis. A combination of ligands act as shape control agents and bond to different facets of the nanorod with different strengths. This allows different faces of the nanorod to grow at different rates, producing an elongated object.

One potential application of nanorods is in display technologies, because the reflectivity of the rods can be changed by changing their orientation with an applied electric field. Another application is for microelectromechanical systems (MEMS). Nanorods, along with other noble metal nanoparticles, also function as theragnostic agents. Nanorods absorb in the near IR, and generate heat when excited with IR light. This property has led to the use of nanorods as cancer therapeutics. Nanorods can be conjugated with tumor targeting motifs and ingested. When a patient is exposed to IR light (which passes through body tissue), nanorods selectively taken up by tumor cells are locally heated, destroying only the cancerous tissue while leaving healthy cells intact.

Nanorods based on semiconducting materials have also been investigated for application as energy harvesting and light emitting devices. In 2006, Ramanathan et al. demonstrated1 electric-field mediated tunable photoluminescence from ZnO nanorods, with potential for application as novel sources of near-ultraviolet radiation.

Titan Maximum

Titan Maximum is an American stop motion animated television series created by Tom Root and Matthew Senreich. The series premiered on Cartoon Network's late night programing block, Adult Swim, from September 27 to November 22, 2009. A teaser premiered during the "Robot Chicken on Wheels" tour and at the 2009 San Diego Comic-Con International. It is a parody of the "Super Robot" anime style produced using stop motion animation.

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