Quantitative structural and textural assessment of laminar pyrocarbons through Raman spectroscopy, electron diffraction and few other techniques

Vallerot, Jean-Marie; Bourrat, Xavier; Mouchon, Arnaud; Chollon, Georges

doi:10.1016/j.carbon.2005.12.029

Cited by 152 publications

(87 citation statements)

References 29 publications

(67 reference statements)

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“…3 summarizes the obtained spectra. The comparison of the obtained Raman spectra with literature ones, did not evidence a clear correspondence with SL, RL or ReL Py-C spectra [15]. This could support the hypothesis of a DL texture.…”

Section: Resultssupporting

confidence: 69%

Cf/C composites: correlation between CVI process parameters and Pyrolytic Carbon microstructure

Burgio

Fabbri

Magnani

et al. 2014

Frattura Ed Integrità Strutturale

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ABSTRACT. Chemical Vapour Infiltration (CVI) technique has been long used to produce carbon/carbon composites. The Pyrolytic Carbon (Py-C) matrix infiltrated by CVI could have different microstructures, i.e. Rough Laminar (RL), Smooth Laminar (SL) or Isotropic (ISO). These matrix microstructures, characterized by different properties, influence the mechanical behaviour of the obtained composites. Tailoring the process parameters, it is possible to direct the infiltration towards a specific Py-C type. However, the factors, influencing the production of a specific matrix microstructure, are numerous and interconnected, e.g. temperature, pressure, flow rates etc. Due to the complexity of the physical and chemical phenomena involved in CVI process, up to now it has not been possible to obtain a general correlation between CVI process parameters and Py-C microstructure. This study is aimed at investigating the relationship between infiltration temperature and the microstructure of obtained Py-C, for a pilot -sized CVI/CVD reactor. Fixing the other process parameters and varying only the temperature, from 1100°C to 1300°C, the Py-C infiltration was performed on fibrous preforms. Polarized light microscopy, with quantitative measurements of average extinction angle (Ae), and Raman spectroscopy were used to characterize the obtained Py-C microstructures.

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Section: Resultssupporting

confidence: 69%

Cf/C composites: correlation between CVI process parameters and Pyrolytic Carbon microstructure

Burgio

Fabbri

Magnani

et al. 2014

Frattura Ed Integrità Strutturale

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“…That was proposed to discriminate, with success, the structure of all the pyrocarbons known at that time. 14 FWHM D is thus the key parameter for scattering the structural axis of the classification: ordinate in Figure 8. As for the abscissa, it is related to the texture or the anisotropy.…”

Section: Multi-scale Structure Of Pyrocarbons By Raman Spectroscopymentioning

confidence: 99%

“…This parameter can be measured by optical microscopy (i.e. Ae, the extinction angle), by TEM (OA, the orientation angle) 14 or R A the Raman anisotropy factor. R A varies experimentally, from 2.2 for the isotropic pyrocarbons up to more than 8 for the highest anisotropic ones.…”

Section: Multi-scale Structure Of Pyrocarbons By Raman Spectroscopymentioning

confidence: 99%

Low temperature pyrocarbons: a review

Bourrat¹,

Langlais²,

Chollon³

et al. 2006

J. Braz. Chem. Soc.

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Este artigo é uma síntese das pesquisas recentes na área dos pirocarbonos. Pirocarbono é uma forma de carbono preparada por deposição química em substratos quentes (acima de 900 °C) mediante pirólise de hidrocarbonetos. Aplicações se encontram nas áreas de materiais compósitos termostruturais, de reatores nucleares ou de biomateriais. Muito recentemente, um avanço importante foi obtido na compreensão dos processos de crescimento. Uma classificação dos pirocarbonos de baixa temperatura é apresentada, que se fundamenta na medição da quantia de defeitos e do grau de anisotropia, fazendo uso da espectroscopia Raman. Ela traz uma relacão bem estabelecida entre mecanismos de crescimento, estrutura e propriedades dos pirocarbonos.This article is a synthetic survey of the recent researches in the field of pyrocarbons. Pyrocarbon is the form of carbon which deposits on hot surfaces above 900°C by cracking of hydrocarbons. Applications are in the fields of composite materials, nuclear reactors or biomaterials. Very recently, an important step was reached concerning the understanding of the growth processes. A classification of the low temperature pyrocarbons is introduced. It is based on the measure of carbon defects and anisotropy, using Raman spectroscopy. It provides a comprehensive relationship between growth mechanisms, structure and properties of pyrocarbons.

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“…The FWHM G of DS pyrocarbon reveals a higher orientation of the graphene layers. The ratio of the D to G peak intensity, I G /I D , is proportional to the degree of graphitization of pyrocarbon in micro-area, and used to evaluate the process parameters on microstructure [6]. The sample (a) show lower values and less drastic change in different deposition ring.…”

Section: Resultsmentioning

confidence: 99%

Growth of Pyrocarbon by Multi-Physics Fields Chemical Vapor Infiltration

Zhang¹

2011

TOMSJ

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A novel rapid chemical vapor infiltration (CVI) processing defined by multi-physics fields CVI was used to fabricate carbon/carbon (C/C) composites. Liquid petrol gas is used as carbon source and the parameters were experimental tested and optimized. The influence of temperature and pressure on the growth of pyrocarbon was investigated in detail. Because of the influence of multi-physics fields, a new surface morpha is grown under control parameters. It is called "Dot Structure". The structure of pyrocarbon is analyzed and characterized by XRD, SEM with EDS, and Raman spectrum. At the end, a simple model of point discharge for growth of pyrocarbon is proposed. The deposited pyrocarbon based on multi-physics fields chemical vapor infiltration is expected to provide an improve performance in rapid C/C composites fabrication.

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Quantitative structural and textural assessment of laminar pyrocarbons through Raman spectroscopy, electron diffraction and few other techniques

Cited by 152 publications

References 29 publications

Cf/C composites: correlation between CVI process parameters and Pyrolytic Carbon microstructure

Cf/C composites: correlation between CVI process parameters and Pyrolytic Carbon microstructure

Low temperature pyrocarbons: a review

Growth of Pyrocarbon by Multi-Physics Fields Chemical Vapor Infiltration

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