New Lines in the Raman Spectra of Carbons and Graphite

Vidano, R.P.; Fischbach, D. B.

doi:10.1111/j.1151-2916.1978.tb09219.x

Cited by 298 publications

(148 citation statements)

References 6 publications

Supporting

Mentioning

137

Contrasting

Unclassified

Order By: Relevance

“…In low crystallinity solids like "SiC" fibers, carbon spectrum mainly consists of a strong "sp 3 -like" resonant contribution and a "sp 2 -like" doublet [2] , as observed in carbon containing films [25][26][27][28][29][30] . The former is fitted by a lorentzian band peaking between 1325cm -1 (under red excitation) and 1365cm -1 (blue excitation).…”

Section: Correlation Between Raman Spectra and Microstructurementioning

confidence: 99%

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Gouadec

Colomban

2001

Journal of the European Ceramic Society

View full text Add to dashboard Cite

The paper provides a comprehensive study on Raman spectroscopy versatility as a fast and non destructive tool for the prediction of the mechanical properties of SiC fibers derived from a polymeric precursor (NLM™, Hi™, Hi-S™, SA™ and Sylramic™ grades) or produced by CVD (SCS-6™ fiber), including in situ analysis in CMCs or MMCs. We show how the results of very simple spectra fitting are correlated with Young's modulus, tensile strength and microhardness. The reason why such a correlation exists, the common dependency of Raman signal and mechanical behavior to the micro/nanostructure of ceramics, is discussed. Keywords :SiC-fibers / Raman spectroscopy / Mechanical properties / Microstructure / Carbon ∂ Author to whom correspondence should be addressed Fax : 33 (0) 1 49 78 13 18 e-mail : colomban@glvt-cnrs.fr IntroductionThe reinforcement of ceramic materials by long ceramic fibers leads to low density and refractory materials, of high damage tolerance, that should be appropriate for metal alloys substitution in advanced engines (turbines) and waste treatment energy plants [1] . Ceramic fibers can also be incorporated directly in metal matrices to increase their high temperature mechanical properties [1] .SiC fibers, which are among the most stable fibers, have always been produced by the 3D reticulation of a polymeric precursor. This synthesis route leads to a high matter homogeneity and very smooth surfaces, the lack of defects explaining tensile strengths σ r as high as 3 GPa. SiC fibers have been widely studied, especially their aging [2][3][4][5][6][7] which evidenced that densification is linked to compositional changes (for instance the loss of some residual hydrogen [8] ). A peculiarity of ceramics issued from polymeric precursors is no impurities are concentrated at the grains boundaries. Abnormal grain growth is very common in the lack of such usual diffusion regulators [9] and the know-how of SiC fibers manufacturers consists in postponing the onset of SiC crystallization and grain growth, since a high correlation is anticipated with mechanical degradation. A close relationship has been evidenced, for instance, between the micro-hardness and short-range ordering in sol-gel prepared nanocrystalline oxides [10] and some authors have already pointed out fibers overall mechanical ability is governed by their microstructure [5,7,11] .The purpose of this paper is to try correlating, to the best extent possible, the tensile strength (σ r ), the Young's modulus (E) and the micro-hardness (μH) of different SiC fibers, either to Raman spectra or to "Raman Extensometry" S coefficient (measuring the straininduced shifts of Raman bands). Unlike most experimental methods intended to measure directly σ r and E, Raman analysis does not require extracting fibers from the matrix, either by mechanical grinding/crushing [12] or by chemical attack [13] . Only the most resistant fibers are extracted in the former case while fibers surface might be altered in the latter. Besides, it will always be difficult to extract...

show abstract

Section: Correlation Between Raman Spectra and Microstructurementioning

confidence: 99%

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Gouadec

Colomban

2001

Journal of the European Ceramic Society

View full text Add to dashboard Cite

show abstract

“…In the present work, the Raman spectroscopy analysis was carried out to examine the reaction mechanism from the viewpoint of bonding structure of carbon atoms in various carbonaceous materials. Although many papers have been published on the structure analysis by the Raman spectroscopic analysis, [4][5][6][7][8][9][10][11][12] the universal evaluation method has not yet been developed for materials which have widely different structure. The Raman spectra of various materials from natural graphite to glassy carbon were compared.…”

Section: Introductionmentioning

confidence: 99%

Structure Analysis of Coke, Wood Charcoal and Bamboo Charcoal by Raman Spectroscopy and Their Reaction Rate with CO2

et al. 2005

View full text Add to dashboard Cite

In order to discuss the reactivity of carbonaceous materials with CO 2 , the Raman spectroscopy analysis was carried out. Nine kinds of materials were examined. The Raman spectra of ordered materials could be assigned to the graphite structure and its defect, but those of disordered materials could not. New parameters were derived to evaluate the structure of the latter. Using the parameters, the structure change was followed during high temperature heat treatment. The disordered material consists of random structure, graphite structure and its defects. The random structure changes to the graphite structure with many defects and the defects decrease with the heat treatment temperature. The reaction rate constant is evaluated. It increases when the structure changes from the random structure to the graphite structure with many defects. After the change, it decreases with decreasing the defects in graphite structure. Thus, the most reactive material should consist of the graphite structure with many defects.KEY WORDS: natural and synthetic graphite; coke; wood charcoal; bamboo charcoal; Raman spectroscopy; reactivity with CO 2 ; new parameters to evaluate structure; structure change during heat treatment; highly reactive material.

show abstract

“…This Raman peak, also known as G band, is related to the energy of sp 2 bonding and is assigned to the normal graphite structure. 4) In less ordered carbonaceous materials, Raman peaks are often observed at 1 360 cm Ϫ1 and 1 620 cm…”

mentioning

confidence: 99%

“…Even though many studies have been reported to use Raman spectroscopic analysis to understand the structure analysis of carbonaceous materials, the understanding of modification of coke carbon structure with increasing temperature is still far from complete particularly the interpretation of Raman analysis. [1][2][3][4][5][6][7][8][9][10][11][12][13] Raman peak of the graphite like materials is well known to appear at 1 580 cm…”

mentioning

confidence: 99%

Characterization of Thermal Annealing Effects on the Evolution of Coke Carbon Structure Using Raman Spectroscopy and X-ray Diffraction

et al. 2006

View full text Add to dashboard Cite

Coke is one of the important materials for ironmaking process such as blast furnace as it plays multiple roles by providing heat energy, performing the role of reducing agent and spacer for maintaining the blast furnace permeability. Due to increasing economic and environmental concerns, there is growing interest in reducing coke consumption by using innovative blast furnace operations such as accelerating coke reactions at relatively lower reactions. In an operating blast furnace, coke carbon structure is continuously modified as it descends towards lower parts of a blast furnace. Evolution coke carbon structure is well known to influence its reactions in a blast furnace such as solution loss reaction and graphitisation. Coke quality issues are becoming increasingly pertinent as less coke would be available to supply sufficient reducing gases under proposed innovative low temperature BF operations. On the hand, graphitisation behaviour could influence its fines generation behaviour in high temperature regions of an operating blast furnace. Therefore, understanding of evolution coke carbon structure at increasing temperatures is very important for the success of any new innovative blast furnace operations.Carbon structure of carbonaceous materials is often characterized by maceral analysis or reflectance measurements which are often subjective in nature and do not distinguish atomic level differences of different carbon types. Recently, advanced analytical tools such as the X-ray Diffraction or Raman Spectroscopy are being developed to characterize carbon structure of different carbonaceous materials includ-1165

show abstract

New Lines in the Raman Spectra of Carbons and Graphite

Cited by 298 publications

References 6 publications

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Structure Analysis of Coke, Wood Charcoal and Bamboo Charcoal by Raman Spectroscopy and Their Reaction Rate with CO2

Characterization of Thermal Annealing Effects on the Evolution of Coke Carbon Structure Using Raman Spectroscopy and X-ray Diffraction

Contact Info

Product

Resources

About