Relationships between interlayer spacing, stacking order and crystallinity in carbon materials

Abstract

the structure of ~u, which is related to that of Ga I in the atomic coordination, will be reported in the context of these phases elsewhere. In the systems mentioned, metastable ~, phases can be retained in quantities up to 100 %, at the appropriate compositions, which permits a better structure analysis of ~ than in the case of ~, (Ga-AI), where a maximum of 25 % ~u was retained by quenching. The rather large metastable solubility of AI in Ga I (up to 8 at. % AI) is again due to the small size difference and identical valence electron concentration of Ga and A1, and is the highest observed solid solubility of any element in Ga I. The various models of graphitization which have been proposed during the past two decades, the assumptions on which they were based, and the related ordering parameters are considered. It is shown that there are apparent inconsistencies in the literature when attempts are made to relate the various ordering parameters calculated for identical materials. The postulated relationships between these ordering parameters and the experimentally determined average interlayer spacing are examined with the use of new data together with those available in the literature. A modification of the Franklin equation has been obtained which more nearly satisfies these experimental data, and it is concluded that none of the classical models is satisfactory over the whole range order in carbon materials. The recent ideas of Maire & M6ring are judged to give a better interpretation of the process of graphitization. Crystallite dimension data have been analysed as general functions of stacking order and the resulting relationships compared with those published in the literature. It is concluded that only general relationships can be indicated, while the more specific relationships must be qualified by comprehensive statements of the correction procedures used. Differences in the behaviour of cokes and artefacts have been found: in order to attain a given degree of stacking order, the constituent crystallites of the artefacts have to be larger than those of the cokes. It is shown that the shape of the crystallites varies with heattreatment temperature and hence with stacking order. Initially the crystallites are plate-like, becoming more cylindrical and columnar with heat-treatment and finally reassuming their initial shape at high temperatures.

Mechanical, Microstructure and Surface Characterizations of Carbon Fibers Prepared from Cellulose after Liquefying and Curing

“…The numerical variation of d (002) is greater than that of d (100) , which is similar to the results of common carbon materials. However, the d (002) of CBCFs is significantly greater than the d (002) of graphite (0.3354 nm) and that of coke (0.3440 nm) at 1000–1350 °C [ 19 , 20 ]. This observation also indicates that, with increasing carbonization temperature, CBCFs is difficult to graphitize.…”

Carbon with Expanded and Well-Developed Graphene Planes Derived Directly from Condensed Lignin as a High-Performance Anode for Sodium-Ion Batteries

“…This indicates that some degree of structural development from disorder to short-range order occurred during the high-temperature carbonization. The interlayer spacing values are larger than those of graphite (0.335 nm), coke prepared at 1000−1350 °C (0.344 nm), 29,30 and most materials carbonized from a variety of precursors (e.g., banana peel, 31 peat moss, 32 sugar, 33 pitch/lignin, 18 argan shell, 34 shaddock peel, 35 hydrogen-enriched reduced graphene oxide, 36 polyacrylonitrile, 37 and corn cob 38 ). As shown in Figure S2 and listed in Table 2, the interlayer spacing in C-1300 is larger than those of O-1300 (0.387 nm) and S-1300 (0.395 nm).…”

Transfer Mechanism of Lanthanum from Rare Earth Containing Iron Ore to Pig Iron during the Blast Furnace Process

“…e insoluble substances were further dissolved by alkali fusion to turn the solid into solution for element analysis. e concentrations of lanthanum in both the ferrite and the insoluble substances were determined using a PerkinElmer Table 4: e relevant expressions of chemical equations, Gibbs free energy, and mass action concentrations of complicated molecules in the molten slag [21][22][23][24].…”