Carbon amorphous hydrogenated

S. Kaplan, F. Jansen, M. Machonkin Characterization of amorphous carbon-hydrogen films by solid-state nuclear magnetic resonance. Appl. Phys. Lett. 47, 750 (1985)... 

Fluorine cannot be prepared directly by chemical methods. It is prepared in the laboratory and on an industrial scale by electrolysis. Two methods are employed (a) using fused potassium hydrogen-fluoride, KHFj, ill a cell heated electrically to 520-570 K or (b) using fused electrolyte, of composition KF HF = 1 2, in a cell at 340-370 K which can be electrically or steam heated. Moissan, who first isolated fluorine in 1886, used a method very similar to (b) and it is this process which is commonly used in the laboratory and on an industrial scale today. There have been many cell designs but the cell is usually made from steel, or a copper-nickel alloy ( Monel metal). Steel or copper cathodes and specially made amorphous carbon anodes (to minimise attack by fluorine) are used. Hydrogen is formed at the cathode and fluorine at the anode, and the hydrogen fluoride content of the fused electrolyte is maintained by passing in... 

Amorphous carbon films may be broadly classified as (i) amorphous carbon films, a-C films, deposited from carbon-containing gases with low or zero hydrogen content [72] and (ii) hydrogenated carbon films, a-C H films, formed from hydrocarbon-containing gases [73,74]. Both types of film contain different amounts of sp and sp bonded carbon. The amount of sp bonded carbon can be estimated from X-ray absorption near edge spectroscopy,... 

The classification of amorphous carbon films according to carbon bond type and hydrogen content can be represented in a triangular diagram, Fig. 6 [e.g., 70]. The comers at the base of the triangle correspond to graphite (100% sp carbon) and diamond (100% sp carbon). The apex represents 100% H, but the upper limit for formation of solid films is defined by the tie line between the compositions of polyethene, -(CH2) -, and polyethyne, -(CH) -. 

Weiler, M., Lang, K., Li, E., and Robertson, J., "Deposition of Tetrahedral Hydrogenated Amorphous Carbon Using a Novel Electron Cyclotron Wave Resonance Reactor, Appl. Phys. Lett., Vol. 72,1998,pp. 1314-1316. 

In reality, several factors were mentioned as being responsible for this behavior, such as variations in bond angle distortion, in the internal stress or in the hydrogen content [40, 76], but all of them are also strongly correlated with the variation of optical gap width in amorphous carbon films. Theoretical work on Raman spectroscopy on DLC materials gave additional support for Dillon s interpretation [77]. 

Around 10% of the dust consists of carbon particles which are about 0.005 pm in diameter. These are amorphous, carbon-containing solids, probably also containing hydrogen. 

Figure 18. Ion beam sputter deposition apparatus for the production of hydrogenated amorphous carbon. (Reproduced with permission from Ref. 26, Copyright 1985, AIP).

Amorphous silicon closer to sp3 material than is Amorphous Carbon Difference due to sp3 states from NMR sp /sp = 3/2 for Maximum Hydrogenation of C. 

Hou et al. [73] considered small "carbon islands" as the main hydrogen-adsorption sites in an MWNT. The hydrogen-storage capacity of a CNT varies widely and the reason for such a variation is not clear, possibly caused by the impurity such as metal catalysts or amorphous carbon. It is not clear yet how the metallic catalyst particles, which are used during the preparation of nanotube samples, affect the hydrogen-storage capacity of nanotubes. 

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