Ultradispersed diamond

Gamamik MY. 1990. Size changes of lattice parameters in ultradisperse diamond and silicon. Phys Status Solidi B 161 457-462. 

Dolmatov VY (2003) Ultradisperse diamonds of detonation synthesis production, properties and applications. State Polytechnical University, St. Petersburg... 

Dolmatov VY. Detonation synthesis ultradispersed diamonds properties and apphca-tions. Rnss Chem Rev 2001 70 607. 

Gavrilkin SM, Bolkhovitinov LG, Batsanov SS (2007) Specifics of the thermal transformations of the wurtzite phase of boron nitride. Russ J Phys Chem 81 648-650 Butenko YV, Kuznetsov VL, Chuvdin AL et al (2000) Kinetics of the grapfaitization of dispersed diamond at low temperatures. J Appl Phys 88 4380-4388 Titov VM, Anisichkin VF, Mal kov lY (1989) Synthesis of ultradispersed diamond in detonation-waves. Comb Expl Shock Waves 25 372-379... 

Kuznetsov, V.L., Chuvilin, A.L., Moroz, E.M. et al., 1994b, Effect of explosions on the structure of detonation soots Ultradisperse diamond and onion carbon. Carbon 32, 873-882. 

A. M. Staver, N. V. Gubareva, A. 1. Lyamkin, E. A. Petrov, Ultradispersed Diamond Powders Obtained with the Use of Explosive Energy , Fizika Goreniya i Vzryva 20, 100-104 (1984). 

Second way to obtain Pd°/Pd in active site is use of ultradispersed diamond (UDD) as support. UDD is one of the new carbon cluster substances that may be produced in large amounts by the detonation method. UDD possesses high specific surface area, almost 300 m /g, with several types of carbonyl functional groups predominant on the surface a highly defective structure, super hardness and chemical stability. It was shown by TEM data, palladium particles are well distributed on the surface of UDD and their size lies in relatively narrow range [3]. This fact provides high activity of catalysts supported on UDD in comparison with activity of activated carbon... 

SA. Kachevskii, E.V. Golubina, E.S. Lokteva, V.V. Lunin, 2007, PaUadhun on Ultradisperse Diamond and Activated Carbon the Relation between Structure and Activity in Hydrodechlorination, Zhumal Fizicheskoi Khimii, 81 (6), 998-1005. 

Comparison of catalytic activity of catalysts prepared by deposition precipitation and deposition from suspension are shown on Fig. 2 by the example of Au/UDD. Ultradispersed diamond was not active in CO oxidation. Interesting result was obtained for 0,05% Au/UDDdp. This catalyst is more active at 250 and 300°C, though the gold content is lowest. At temperatures 350 and 400°C CO conversion is nearly the same in the presence of catalysts prepared by DP. Catalysts prepared by DS at these temperatures have lower activity CO conversion was only 35%. Such behavior most likely related with electronic state of supported metal. Activity of gold catalysts in CO oxidation depends on metal charge [4]. 

In Chapter 2, the development of composite materials based on improved nanodiamonds is reported by P. Ya Detkov, V. A. Popov, V. G. Kuhchikhin and S. I. Chukhaeva. The authors describe methods for improving the quality of diamond nanopowders obtained by detonation synthesis, as well as some commercial applications of nanodiamonds. The authors prove that the synthetic detonation diamond is a promising material that can be used in many fields. Of special interest are its applications in compos ite materials both with a metal and polymer matrix. Commercial production of ultradisperse diamonds (or nanodiamonds) has been developed, and it is synthesized on a scale sufficient for particular industries. 

Diamond particles formed in the detonation synthesis ate 2-6 nm in size. Particles of detonation diamond have a cubic lattice with lattice parameter a = 0.3575 nm (in natural diamond, a = 0.3566 nm). Due to the small size of particles, the detonation diamonds are called ultradisperse diamonds (UDD) or nanodiamonds. 

Thus, purification of ultradisperse diamond in the production process yields powders or suspensions of the above quality of the solid phase. They are called type or standard powders/suspensions. Pure powders/suspensions are those with lower impurity content. 

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 ... 

After the purification by these methods, incombustible impurities and oxidized forms of carbon in the synthesized powders were assayed. For some samples, the pycnometric density was determined. The efficiency of the methods used to produce pure powders of ultradisperse diamonds was assessed based on these solid-phase parameters (Table 2.1). 

Calculated from the shape of the lines, the distribution of ultradisperse diamond particles by size on the X-ray patterns of UDD samples gives the values 10-100 A with the average size of 31 A. Small-angle X-ray scattering determines the fractal character of nanoparticles with the size of 18 A. 

The most developed application of UDD is their use for strengthening composite electrochemical chromium-based coatings. Ultradisperse diamond is introduced into the standard chromium-plating electrolyte usually as suspension. The... 

Ultrasmall size of primary particles, specificity of stracture formation processes, extremely high dispersity and specific surface, coordination unsaturation of surface atoms of carbon, and the presence of functional groupings on them, all these significantly distinguish detonation diamonds from natural diamonds and static-synthesis diamonds. As the detonation method of UDD synthesis developed, it became clear that ultradisperse diamonds could have not only traditional but also absolutely new applications. 

The tests show that addition of UDD and UDD-based materials to oils and lubricants is multifunctional. The major difficulty impeding the research in this direction is due to the insufficient sedimentation stability of UDD oil suspensions. If and when this problem is solved, a promising application of UDD suspension is its use in motor oil as an additive to fuels for two-stroke gasoline engines. In this case, the additives can improve the lubricating characteristics of fuel and, at the same time, increase its calorific value. RFNC-VNIITF carries out research on the separation of ultradisperse diamond powder into nanometer-range fractions, capable of yielding stable suspensions in various liquids. 

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