Study of Nicalon-based ceramic fibres and powders by EXAFS spectrometry, X-ray diffractometry and some additional methods

Laffon, C.; Flank, A.M.; Lagarde, P.; Laridjani, M.; Hagège, R.; Olry, Pierre; Cotteret, J.; Dixmier, J.; Miquel, J.L.; Hommel, H.; Legrand, A.P.

doi:10.1007/bf02397093

Cited by 207 publications

(40 citation statements)

References 11 publications

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“…NLM Raman spectrum has a strong shoulder on the low frequency-side of the "sp 3 -carbon" band, which is best seen under red excitation [69] . It must be related to the hydrogen that was shown to surround carbon precipitates [70] (C-C vibrations disturbed by C-H bonding). The band narrowing observed in the Hi-Nicalon with respect to NLM spectra is consistent with a greater size of carbon precipitates and an increasing organization.…”

Section: Raman Spectroscopy and Sic Fibers Micro/nano-structurementioning

confidence: 99%

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Gouadec

Colomban

2001

Journal of the European Ceramic Society

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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...

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Section: Raman Spectroscopy and Sic Fibers Micro/nano-structurementioning

confidence: 99%

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Gouadec

Colomban

2001

Journal of the European Ceramic Society

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“…Strength and creep resistance where not as expected either. Extensive study [43,[101][102][103][104][105][106][107][108][109][110][111][112] of these first generation fibers found that these fibers begin to lose their creep resistance and short-term strength at 1000…”

Section: Non-oxide (Sic) Fibersmentioning

confidence: 99%

Creep of Hi-Nicalon S Ceramic Fiber Tows at 800 deg C in Air and in Silicic Acid-Saturated Steam

Robertson¹

2015

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“…The Si-C-O fibers are a mixture of b-SiC nanocrystals, free carbon, and an amorphous silicon oxycarbide SiC x O y phase. 11,13,[44][45][46][47] The microstructure of the Si-C fibers is a mixture of larger b-SiC crystallites, with larger amounts of glassy carbon, and a very small amount of SiC x O y phase in comparison with the Si-C-O fibers.…”

Section: Microstructure Of Si-c-o Fibers and Low-oxygenmentioning

confidence: 99%

SiC-Based Ceramic Fibers Prepared via Organic-to-Inorganic Conversion Process-A Review

清人¹,

聰夫

賢太郎

et al. 2006

J. Ceram. Soc. Japan

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Review péÉÅá~ä fëëìÉ Äó dìÉëí bÇáíçêëW lêÖ~åáÅ-íç-fåçêÖ~åáÅ`çåîÉêëáçå mêçÅÉëë Ñçê mçäóãÉê-aÉêáîÉÇ`Éê~ãáÅë pá`_~ëÉÇ`Éê~ãáÅ cáÄÉêë mêÉé~êÉÇ îá~lêÖ~åáÅíçfåçêÖ~åáÅ çåîÉêëáçå mêçÅÉëë-^oÉîáÉï ሱᑿ-ᠪᑿং၁ɟɵɃɁǺȗȚ SiC ṾɃɱɧɋȷέỺǽ۰༔ ἕ◻Several types of Si-based ceramic fibers have been prepared using an organic-to-inorganic conversion process. In this article, the preparation, microstructure, and high-temperature stability of SiC-based ceramic fibers prepared from polycarbosilane of an organosilicon polymer are reviewed. The first fiber produced was an amorphous Si-C-O fiber, next was a low-oxygen content Si-C fiber, and finally, a nearly stoichiometric SiC fiber was developed. These fibers are continuous fine fibers that have high tensile strength with high heat resistance. The pyrolytic behavior and active-passive oxidation of these fibers at high temperatures are described here. The heat resistance of these fibers increases in the order of the Si-C-O fiber, the Si-C fiber, and the SiC fiber. The hightemperature properties are dependent on the atomic arrangement and the quantity of amorphous SiC x O y and glassy carbon in the fibers. Possible applications for these fibers are as refractory materials, and as reinforcement fibers for plastics, metals, and ceramics.

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Study of Nicalon-based ceramic fibres and powders by EXAFS spectrometry, X-ray diffractometry and some additional methods

Cited by 207 publications

References 11 publications

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Non-destructive mechanical characterization of SiC fibers by Raman spectroscopy

Creep of Hi-Nicalon S Ceramic Fiber Tows at 800 deg C in Air and in Silicic Acid-Saturated Steam

SiC-Based Ceramic Fibers Prepared via Organic-to-Inorganic Conversion Process-A Review

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