A reconsideration of the relationship between the crystallite size L_a of carbons determined by X-ray diffraction and Raman spectroscopy

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• 作者：Gerald A. Zickler ; Bernd Smarsly ; Notburga Gierlinger ; Herwig Peterlik and Oskar Paris
• 关键词：Charcoal ; Carbon fibers ; Raman spectroscopy ; X-ray diffraction ; Microstructure
• 刊名：Carbon
• 出版年：2006
• 出版时间：December 2006
• 年：2006
• 卷：44
• 期：15
• 页码：3239-3246
• 全文大小：336 K

文摘

Non-graphitic carbon materials produced by pyrolyzing wood at temperatures from 400 to 2400 °C and various types of commercial carbon fibers were examined by X-ray diffraction and Raman spectroscopy. The specimens cover a wide range of crystallite sizes L_a, in particular also very small sizes below 2 nm. The X-ray data were evaluated using the Scherrer equation and by an advanced approach using full curve fitting. The ratio of the D/G band intensities was determined from the Raman data by different evaluation techniques. A critical assessment of the classical linear relationship between 1/L_a and the D/G ratio shows that the relationship breaks down for crystallite sizes below 2 nm in accordance with recent theoretical predictions. The results are compared with data from the literature, showing that there are additional discrepancies between the data from various carbon types at large L_a due to different methods of data evaluation.