Microcrystalline graphite

According to the characterizations by TEM and XRD, the sample prepared from a CH4/H2 plasma was composed of nanocrystalline diamond and disordered microcrystalline graphite. Then nondiamond carbon was effectively removed with an increase in [CO]. It is therefore concluded that the VDOS of the nanocrystalline diamond and DEC films extracted from the HREELS data is in qualitative agreement with the characterizations of TEM and XRD. Although the HREELS probes only the region near the surface, the agreement suggests that the surface dynamics do not differ dramatically from those of the bulk. 

C. Graphite ordering increases with temperature. Formation of microcrystalline graphite and millimeter-size graphite crystals occurs above the eutectic point in the Fe/Fe3C system. 

Kaneko K, Ishii C, Ruike M, and Kuwabara H. Origin of superhigh surface-area and microcrystalline graphitic structures of activated carbons. Carbon, 1992 30(7) 1075-1088. 

Hardwick L, Hahn M, Ruch P, Holzapfel M, Scheifele W, Buqa H, Krumeich F, Novak P, Kotz R. An in situ Raman study of the intercalation of supercapacitor-type electrolyte into microcrystalline graphite. Electrochimica Acta 2006 52 675-680. 

Chlorination of FesC at temperatures of 400°C and above results in the formation of carbon and solid or gaseous iron chlorides. Three temperature regimes have been defined. Amorphous carbon is formed at temperatures of 400 - 500°C. Flakes and ribbons of nanocrystalline graphite form at 600 -1100°C. Graphite ordering increases with temperature. Formation of microcrystalline graphite and millimeter-size graphite crystals occurs above the eutectic point in the Fe/FcsC system. 

Hydrothermal formation of carbon on SiC was first observed in the course of corrosion studies of amorphous Si-Ti-C-O (Tyranno) fibers performed at 300-800°C at about 100 MPa [47,48,53]. Increasing downshift of the carbon D band in the Raman spectra with increasing reaction temperature from 1355-1360cm in microcrystalline graphite to 1350cm , 1336 cm , and 1330 3cm after hydro-thermal treatments at 300°C, 500°C, and 600-800°C respectively indicated the possible formation of sp -bonded carbon [50]. 

Nuclear and electronic stopping, which are functions of incident ion energy, result in different internal cluster structures [6]. Close to the surface, where electronics stopping dominates, the material consists of three-dimensional networks of amorphous carbon and microcrystalline graphite. Within the surface, close to the mean range of the ions, the material consists of a fractal or one-dimensional network of dangling bonds, broken chains, and free radicals. 

These include activated carbon, carbon black, microcrystalline graphite, and nanostructured carbons [16,17]. However, it should be pointed out that compared to steam reforming of methane, which is a commercialized process, hydrogen production from methane decomposition requires more research on more durable catalysts. A recent review of hydrogen production via hydrocarbon decomposition can be found in Ahmed et al. [18]. 

Figure 9.7 shows a typical Raman spectrum of DND powder and those of microcrystaUine diamond powder (the grain size of 200 xm) and microcrystalline graphite. One can clearly see the features mentioned above the broadening and freqnency shift of the diamond mode, as well as a new band due to microcrystalline graphite. ... 

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