Structure and properties of interlayers in polymer-derived C/SiC composites

Ostertag, R.; Haug, Tilman; Woltersdorf, J.; Pippel, Eckhard; Hähnel, Angelika; Schneider, Reinhard

doi:10.1016/0955-2219(94)90081-7

Cited by 2 publications

(2 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The SiC matrix was produced by infiltration and pyrolysis of Si polymers (cf. [3]). For a good mechanical composite behaviour, particularly with respect to a friction-hindered gliding of the fibres during pull-out, the fibres were coated with approximately 30 to 50 nm of carbon, which was pyrolytically deposited by using acetylene or ethylene as the reaction gas and N 2 as the carrier gas.…”

Section: Methodsmentioning

confidence: 93%

“…F o r m e r E D X S investigations revealed a local accum u l a t i o n of nitrogen and silicon within the pyrolytically deposited carbon exhibiting the characteristic bright-dark contrast m o d u l a t i o n s (see [3]). In addition, unlike the interior of the matrix, on its side to the interface there is a 20 nm wide zone rich in oxygen.…”

Section: C-fibre Reinforced Sicmentioning

confidence: 97%

See 1 more Smart Citation

EELS nanoanalysis for investigating both chemical composition and bonding of interlayers in composites

1997

View full text Add to dashboard Cite

Abstract. The paper is concerned with the application of analytical transmission electron microscopy (TEM) to characterize both chemical composition and bond state of the elements detected in interlayers in C-and SiC-fibre reinforced composites. The chemical bond state of nanometre-sized regions is characterized by means of electron energy loss spectroscopy (EELS), where respective information is gained by analysing energy loss near edge structures (ELNES). In this context results of Si-L23 ELNES investigations are presented concerning the chemical bonding of silicon with carbon, nitrogen and oxygen. The specific bond state of silicon is revealed by recording series of EEL spectra at high energy resolution across the fibre/ matrix interlayers of interest. Moreover, the element distribution is imaged by energy-filtered TEM.Key words: analytical transmission electron microscopy, electron energy loss spectroscopy, energy loss near edge structure, chemicalbond characterization, fibre-reinforced materials, interlayer microchemistry.Interfaces are more or less abrupt structural and chemical transitions of sometimes only nanometre or even atomic dimensions. Phenomena correlating with interfaces or interlayers, respectively, are of great importance in materials science as they can essentially determine the materials properties. Owing to the dimensions mentioned above, different methods of electron microscopy are necessary for interface analysis. In particular, high-resolution transmission electron microscopy (HREM) and analytical microscopy (AEM) are required to characterize both microstructure and microchemistry of interfaces or interlayers, respectively.In the field of AEM, allowing a comprehensive materials examination of thin layers of some 10 * Dedicated to Professor Dr. rer.nat. Dr. b.c. Hubertus Nickel on the occasion of his 65th birthday ** To whom correspondence should be addressed nanometers, or less, in thickness by combining imaging and spectroscopic electron microscope techniques, the use of EELS is continuously increasing. In general, energy-dispersive X-ray spectroscopy (EDXS) and EELS complement each other reasonably well as EDXS is especially sensitive to heavy elements, and vice versa EELS is highly efficient in detecting elements of atomic numbers Z = 3, 4, 5, 6... etc.But, owing to its high energy resolution, in the order of 0.5 to 1 eV, EELS yields additional information as, e.g., on the bonding state or the oxidation level of the elements present in the transmitted volume. Such an information can be derived from energy loss near edge structures (ELNES), which are visible in the energy loss range up to about 30eV above the edge onset and arising from transitions of core-shell electrons into unoccupied states above the Fermi level (see, e.g., [1, 2 l). As the density of unoccupied states depends on atomic symmetry and bonding configurations the whole atomic environment can be characterized, i.e., not only the bonding but also the coordination of and distances between neighbouring atoms. As criteria of...

show abstract

Section: Methodsmentioning

confidence: 93%

Section: C-fibre Reinforced Sicmentioning

confidence: 97%