Nanodiamond powder

Recently Butler et al. [4] reported the deposition of nanocrystalline diamond films with the conventional deposition conditions for micrometer-size polycrystalline diamond films. The substrate pretreatment by the deposition of a thin H-terminated a-C film, followed by the seeding of nanodiamond powder, increased the nucleation densities to more than 10 /cm on a Si substrate. The resultant films were grown to thicknesses ranging from 100 nm to 5 fim, and the thermal conductivity ranged from 2.5 to 12 W/cm K. 

The spectral features d d transform into broad peculiarity tf after diamond nanopowder Alit treatment in hydrogen. As a result, after diamond nanopowder Alit treatment, its CXa-emission band becomes similar to reference refined diamond powder (Fig. le). So far as nanodiamond powders CKa-bands investigation was carry out at minimum anode current densities (1 mA), the unrefined diamond powder surface remained chemisorbed atoms and molecules. However, owing to electron bombardment in sample emission focus, some of chemisorbed atoms disappeared. Therefore it was important to obtain CA -spectra... 

Osswald S, Yushin G, Mochalin V, Kucheyev S et al (2006) Control of sp2/sp3 carbon ratio and surface chemistry of nanodiamond powders by selective oxidation in air. J Am Chem... 

Mochalin VN, Osswald S, Portet C, Yushin G et al (2008) High temperature functionalization and surface modification of nanodiamond powders. Mater Res Soc Symp Proc 1039 1039-P11-03... 

The high thermal conductivity can be employed for nanodiamond applications as well. It is possible to prepare, for example, heat-conducting pastes. The material demand is only l-10gm here. Another positive effect of using the nontoxic nanodiamond powder is to avoid the customary, very poisonous paste of beryUium oxide in some of these applications. 

C. Deng, M. Liu, P. Mohan, Nanodiamond powder compaction via laser shockwaves Experiments cuid finite element cuicdysis. Powder Technology, 239, 36-46, 2013. 

T. Kondo, 1. Neitzel, V.N. Mochalin, J. Urai, M. Yuasa, Y. Gogotsi, Electrical conductivity of thermally hydrogenated nanodiamond powders, Journal of Applied Physics, 113 (21), 214307,2013. 

Y.-J. Zhai, Z.-C. Wang, W. Huang, J.-J. Huang, Y.-Y. Wang and Y.-Q. Zhao, Improved mechanical properties of epoxy reinforced by low content nanodiamond powder, Materials Science and Engineering A, 528 (24), 7295-7300, 2011. 

Due to its unique physicochemical characteristics, diamond is widely used in industry. Interest in fabrication of artificial diamond crystals, specifically, those obtained by detonation transformation of explosives, was already evinced in the 1940s. Attention was paid to the fact that thermodynamic conditions for the existence of carbon as diamond crystals are realized in the zone of the detonation complex. Nanodiamond powder synthesis and the properties of synthesized materials were studied in numerous works performed at various research centers [1-11]. In subsequent decades, many attempts were undertaken to develop detonation diamond technology. One of these technologies was developed and patented by the Russian Federal Nuclear Center-Zababakhin All-Russian Research Institute of Technical Physics (RFNC-VNIITF). 

Metal impurities are removed from nanodiamond powders by dissolving them in mixtures of strong inorganic acids. 

The nanodiamond powder is separated from the suspension by centrifugation and drying at 150°C. 

Nanodiamonds synthesized in the standard process contain nondiamond forms of carbon, metal, and silicon compounds as major impurities. Metal impurities include compounds from the diamond-containing mixture that were not dissolved during oxidation or were formed during purification (mainly chromium hydroxide and major chromium sulfates). Production of pure powders requires additional expenditures, and the effect of this or that impurity on particular consumer properties of ultradisperse diamond remains an open issue. Nanodiamond powders were obtained in a more pure form with respect to ... 

From nanodiamonds (powders and snspensions) pnrified by the standard process by retreatment with snlfuric acid and chrominm anhydride at various ratios... 

Table 2.1 Characteristics of nanodiamond powders obtained by various purification techniques.

By alkaline treatment of nanodiamond powders and suspensions purified in the standard process... 

Nanodiamond powder technology began to be rapidly developed in the mid-1980s. UDD is close to this class of materials by its characteristics. A large body of information on the positive effect of nanofillers on the mechanical properties of various composite materials, polymer composites included, appeared in the patent and technical literature. Still, in spite of UDD evidently being technically... 

Polymers containing a nanodiamond powder filler find wide nse. Nanodiamond powder fillers are added into polymers to enhance their strength and increase their elasticity modnlns. These effects depend on the natnre of the polymer and filler, their interaction, and on how discrete the filler particles are. The effect of strength increase is the most pronounced at the addition of highly disperse fillers to elastomers. In the case of amorphous plastics, the effect of the elasticity modulus increase predominates. 

Of significant interest is the use of nanodiamond powders for strengthening polymer materials. Nanopowders of oxides obtained from clay are used for these purposes at present. In commercial production of nanopowders by detonation the cost of nanodiamond powders and nanooxides obtained from clay becomes commensurate. That is, there are almost no obstacles of economic character for broad introduction of diamond nanopowders. 

This work studied the mechanical characteristics of amorphous plastic styrene acrylonitrile copolymer (SAN). Nanodiamond powder particles (2.5, 5, and 10%) were added to copolymer granules and mixed in a microextruder-type mixer (auger diameter, 9 mm 2rpm, 200°C, mixing time 5 min). Samples of the mixture as extrudates were tested at room temperature on an Instron testing machine. 

Table 2.4 Effect of nanodiamond powders on the mechanical properties of polymer materials.

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